Bazaar – php example code – part 8 – shopping cart of user

Article focus on way of implementation of user shopping cart. Our bazar_item table is altered for new field cart_number. If cart number is zero, item is not added into a buyer cart. After adding item into a cart, this number is changed to a number of buing user. Showing content of cart relays on display bazaar_itmes marked by users_id of appropriate user.

Way how to implement shopping cart

Shopping cart will display all items added by appropriate user for further revision and commitment to buy.

In our cart page we must be able to do:

display all items added to buy by a single user
enable delete items from cart
calc total price for items in cart
delivery adress can be updated by editinfo.php page, here is only displayed content
after definitive submitting, send info to seler by e-mail about succesfull buy

Cart is available only for loged in users, also loged in user can commit buy to a seler/ sellers of selected items.

For further improvement or consideration is way how to inform sellers about succesull buy. Our simle solution send one e-mail for one item. But there is not a small possibility, tahat cart can contain more items from one seler. For all of these items is send to seler one buy commitment request.

Visual look of shopping cart

Next pictures show content of our shopping cart and related scripts output.

Displayed info about not selected comitting YES for BUY

Succesfully submited buy with notification about contacting of sellers for that items

Implementation of shopping cart

Next code shows how shopping cart is implemented in our aplication.

<!– ***************************************************************** –>

<!– PHP „self“ code showing content of items added into a cart –>

<!– ***************************************************************** –>

<!– Vrsion: 1.0 Date: 1.11.2020 by CDesigner.eu –>

<!– ***************************************************************** –>

<!– ***************** MEMO – base is from index.php – show all items with cart_number = session(users_id) + calc total summ, create remove from cart link with removefromcart.php show address for delivery and button submitt to buy ************************************ –>

<?php

require_once(‚appvars.php‘); // including variables for database

session_start(); // start the session – must be added on all pages for session variable accessing

// solution using SESSIONS with COOKIES for longer (30days) login persistency

if(!isset($_SESSION[‚users_id‘])) { // if session is no more active

if(isset($_COOKIE[‚users_id‘]) && isset($_COOKIE[‚username‘])) { // but cookie is set then renew session variables along them

$_SESSION[‚users_id‘] = $_COOKIE[‚users_id‘];

$_SESSION[‚username‘] = $_COOKIE[‚username‘];

$_SESSION[‚user_role‘] = $_COOKIE[‚user_role‘]; // added for role

}

// two variables for message and styling of the mesage with bootstrap

$msg = “;

$msgClass = “;

// default values of auxiliary variables

$name_of_item = „“;

$price_eur = „“;

$subcategory_id = „“;

$users_id = „“;

$item_add_date = „“;

$subcategory_id = „“;

$published = false;

$screenshot1 = „“;

$screenshot2 = „“;

$screenshot3 = „“;

$item_description = “;

$is_result = false; //before hitting submit button no result is available

// Control if data was submitted

if(filter_has_var(INPUT_POST, ‚submit‘)) {

// Data obtained from $_postmessage are assigned to local variables

if($_POST[‚confirm‘] == ‚Yes‚ ){ // if yuser selected YES and hit Buy button on below of the page

//read all data from $_POST array

$users_id = htmlspecialchars($_POST[‚users_id‘]);

/***********************************************************

* obtain data about buyer

// read data about buying user with users id from database

// make database connection

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PW, DB_NAME);

// Check connection

if($dbc === false){

die(„ERROR: Could not connect to database. “ . mysqli_connect_error());

}

//– only one needed — geting users data for purchase e-mail

$sql = „SELECT * FROM bazaar_user WHERE users_id = „.“‚$users_id'“.“LIMIT 1″ ;

if($output = mysqli_query($dbc, $sql)){

if(mysqli_num_rows($output) > 0){ // if any record obtained from SELECT query

while($row = mysqli_fetch_array($output)){ //next rows outputed in while loop

$first_name_buyer = $row[‚first_name‘];

$lastname_name_buyer = $row[‚lastname_name‘];

$addresss_buyer = $row[‚addresss‘];

$city_buyer = $row[‚city‘];

$ZIPcode_buyer = $row[‚ZIPcode‘];

$email_buyer = $row[‚email‘];

}

// Free result set

mysqli_free_result($output);

} else{

echo „No info about buyer obtained.“; // if no records in table

}

} else{

echo „ERROR: Could not able to execute $sql. “ . mysqli_error($dbc); // if database query problem

};

/**************************************************************

* obtain data buyed items from this buyer with users_id defined by current SESSION

//get info about sold items – we must go through all buyed items and send emaily one by one for all diferent selers of item (first approach for all item one)

$sql = „SELECT * FROM bazaar_item WHERE cart_number = „.“‚$users_id'“ ;

if($output = mysqli_query($dbc, $sql)){

if(mysqli_num_rows($output) > 0){ // if any record obtained from SELECT query

while($row = mysqli_fetch_array($output)){ //next rows outputed in while loop

$item_id = $row[‚item_id‘];

$name_of_item = $row[‚name_of_item‘];

$price_eur = $row[‚price_eur‘];

$users_id_of_seller = $row[‚users_id‘];

/******************************************************

* sent info to seler item by item in the buyer cart

// send appropriate e-mails about buy items by items

// validate e-mail

if(filter_var($email_buyer, FILTER_VALIDATE_EMAIL) === false){

// E-mail is not walid

$msg = ‚Wrong e-mail format of buyer, purchase can not be created. Please contact page admin.‘;

$msgClass = ‚alert-danger‘;

} else {

// E-mail is ok

$is_result = true;

/* request e-mail of seller */

/****************************************************

* obtain e-mail of appropriate seller – this is done for all buying items one by one

$sql2 = „SELECT email FROM bazaar_user WHERE users_id = „.“‚$users_id_of_seller'“ ;

if($output2 = mysqli_query($dbc, $sql2)){

if(mysqli_num_rows($output2) > 0){ // if any record obtained from SELECT query

while($row = mysqli_fetch_array($output2)){ //next rows outputed in while loop

$email_of_seller = $row[‚email‘];

}

// Free result set

mysqli_free_result($output2);

} else{

echo „No email about seller can be obtained.“; // if no records in table

}

} else{

echo „ERROR: Could not able to execute $sql2. “ . mysqli_error($dbc); // if database query problem

};

/****************************************** * construct information e-mails about item buy one by one for all items in cart

$toEmail = $email_of_seller; //!!! e-mail address to send to

$subject = ‚Item ‚.$name_of_item.‘ purchased on Bazaar by ‚.$first_name_buyer.‘ ‚.$lastname_name_buyer;

$body = ‚<h2>Item ‚.$name_of_item.‘ was succesfully purchased by : ‚.$first_name_buyer.‘ ‚.$lastname_name_buyer.'</h2>

<h4>Delivery adress for this purchase is: </h4><p>‘.$addresss_buyer.‘,</p><p> ‚.$city_buyer.‘, </p><p>‘.$ZIPcode_buyer.'</p>

<h4>Email</h4><p>E-mail of buyer is‘.$email_buyer.‘ this e-mail can be used for further communication.</p>

<h4>Selling price was:</h4><p‘.$price_eur.‘ €.</p>

‚;

// Email Headers

$headers = „MIME-Version: 1.0″ .“\r\n“;

$headers .=“Content-Type:text/html;charset=UTF-8″ . „\r\n“;

// Additional Headers

$headers .= „From: “ .$first_name_buyer. „<„.$email_buyer.“>“. „\r\n“;

if(mail($toEmail, $subject, $body, $headers)){

// Email Sent

$msg .= ‚<p> Your seller of ‚.$name_of_item.‘ was successfully contacted via e-mail.</p>‘;

$msgClass = ‚alert-success‘;

} else {

// Failed

$msg = ‚Information about your buy cannot be delivered to seller via e-mail. Please contact site admin for further help.‘;

$msgClass = ‚alert-danger‘;

}

// Free result set

mysqli_free_result($output);

} else{

echo „No info about buyer obtained.“; // if no records in table

}

} else{

echo „ERROR: Could not able to execute $sql. “ . mysqli_error($dbc); // if database query problem

};

// close database connection

mysqli_close($dbc);

} else {

echo ‚<p class=“alert alert-danger“ > The selected operation cannot be performed. Please select YES for further buy confirmation. </p>‘;

}

};

<!– **************************************** –>

<!– HTML code containing Form for submitting –>

<!– **************************************** –>

<!DOCTYPE html>

<html>

<head>

<title> Bazaar Cart </title>

</head>

<body>

<?php // generate menu if user is loged in or not

// old solution with cookies if(isset($_COOKIE[‚username‘])) { // loged in user

if(isset($_SESSION[‚username‘])) { // loged in user

echo ‚<a class=“navbar-brand“ href=“index.php“>Bazaar – best items for a best prices!</a>‘;

echo ‚<a class=“navbar-brand“ href=“editprofile.php“> Edit profile </a>‘;

echo ‚<a class=“navbar-brand“ href=“logout.php“> Logout ‚ .$_SESSION[‚username‘] .'</a>‘;

if(isset($_SESSION[‚user_role‘])==’admin‘) { // if oged user is admin role

echo ‚<a class=“navbar-brand“ href=“admin.php“> Manage your page </a>‘;

};

require_once(‚sell_icon.php‘); // graphic menu item for selling your items

require_once(‚cart_icon.php‘); // small cart icon in menu

} else { // visitor without login

echo ‚<a class=“navbar-brand“ href=“login.php“> Log In </a>‘;

echo ‚<a class=“navbar-brand“ href=“signup.php“> Sign Up for better membership! </a>‘;

echo ‚<a class=“navbar-brand“ href=“index.php“>Bazaar – best items for a best prices!</a>‘;

}

</div>

</nav>

<?php if($msg != “): ?>

<?php endif; ?>

<br>

<br>

<h4> Cart item of user

<?php echo $_SESSION[‚username‘]; // creating title of cart for users

echo “ with id – {$_SESSION[‚users_id‘]} are:“;

<br>

</h4>

<!– Showing content of the cart of appropriate user with items marked with users_id in filed cart_number –>

<?php

/* Attempt MySQL server connection. Assuming you are running MySQL

server with default setting (user ‚root‘ with no password) */

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PW, DB_NAME);

// Check connection

if($dbc === false){

die(„ERROR: Could not connect to database – stage of article listing. “ . mysqli_connect_error());

}

// read all rows (data) from guestbook table in „test“ database

$_usr_id = $_SESSION[‚users_id‘];

$sql = „SELECT * FROM bazaar_item WHERE cart_number=“.“‚$_usr_id'“.“ ORDER BY item_id ASC „; // read items marked in cart_number with appropriate users_id

/**************************************************************/

/* Output in Table – solution 1 – for debuging data from database */

/**************************************************************/

// if data properly selected from guestbook database tabele

echo „<br>“;

echo „<br>“; echo „<br>“;

if($output = mysqli_query($dbc, $sql)){

if(mysqli_num_rows($output) > 0){ // if any record obtained from SELECT query

// create table output

echo „<table>“; //head of table

echo „<tr>“;

//echo „<th>id</th>“;

echo „<th>Name</th>“;

echo „<th>Price</th>“;

echo „<th>Category</th>“;

echo „<th>Screenshot1</th>“;

echo „<th>More info</th>“;

echo „</tr>“;

$cart_total_eur = 0; // initialize cariable calculating total price for items in cart

while($row = mysqli_fetch_array($output)){ //next rows outputed in while loop

echo “ <div class=\“mailinglist\“> “ ;

echo „<tr>“;

//echo „<td>“ . $row[‚item_id‘] . „</td>“;

echo „<td class=\“item_name\“>“ . $row[‚name_of_item‘] . „</td>“;

echo „<td class=\“price\“>“ . $row[‚price_eur‘] . “ € </td>“;

$cart_total_eur += $row[‚price_eur‘];

* convert category_id in to category and subcategory */

$subcategory_id = $row[‚subcategory_id‘];

$category_idsupl = „“ ;

$subcategory_idsupl = „“ ;

// (*) — conversion of category and subcategory into category%id

// create SELECT query for category and subcategory names from database

$sql_supl = „SELECT category, subcategory FROM bazaar_category WHERE subcategory_id = „.“‚$subcategory_id'“ ;

/*$output_supl = mysqli_query($dbc, $sql_supl);

$row_supl = mysqli_fetch_array($output_supl);

$category_id = $row_supl[‚category‘] ;

$subcategory_id = $row_supl[‚subcategory‘] ;

echo „<td>“ . $category_id.“/“.$subcategory_id.“</td>“;*/

// execute sql and populate data list with existing category in database

if($output_supl = mysqli_query($dbc, $sql_supl)){

if(mysqli_num_rows($output_supl) > 0){ // if any record obtained from SELECT query

while($row_supl = mysqli_fetch_array($output_supl)){ //next rows outputed in while loop

$category_idsupl = $row_supl[‚category‘] ;

$subcategory_idsupl = $row_supl[‚subcategory‘] ;

}

// Free result set

mysqli_free_result($output_supl);

} else {

echo „There is no souch category-subcategory in category table. Please correct your error.“; // if no records in table

}

} else{

echo „ERROR: Could not able to execute $sql. “ . mysqli_error($dbc); // if database query problem

}

echo „<td>“ . $category_idsupl.“/“.$subcategory_idsupl.“</td>“;

$image_location = IMAGE_PATH.$row[‚screenshot1‘];

echo „<td id=\“gray_under_picture\“> <img src=\“$image_location\“ alt=\“ screenshot of product primary \“ height=\“250\“> </td>“;

echo ‚<td colspan=“1″><a id=“DEL“ href=“removefromcart.php?cart_number=‘.$row[‚cart_number‘]. ‚&item_id=‘. $row[‚item_id‘] . ‚&name_of_item=‘. $row[‚name_of_item‘] .'“> >> Remove from cart </a></td></tr>‘; //construction of GETable link

echo „</tr>“;

echo “ </div> “ ;

}

echo „</table>“;

echo „<br><br>“;

echo „<p><center><h5>Total price for items in cart: <strong> $cart_total_eur </strong>€ </h5></center></p>“;

// Free result set

mysqli_free_result($output);

} else{

echo „There is no item for sell. Please add one.“; // if no records in table

}

} else{

echo „ERROR: Could not able to execute $sql. “ . mysqli_error($dbc); // if database query problem

}

// Close connection

mysqli_close($dbc);

<!– Recapitulation of user delivery adress – important beacause is sent to seller with e-mail about succesfull buy of listened item –>

<h4> Your delivery adress is: </h4>

<?php

// connect to a database

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PW, DB_NAME);

// Check connection

if($dbc === false){

die(„ERROR: Could not connect to database – stage of article listing. “ . mysqli_connect_error());

}

// get info about user from database

$users_id = $_SESSION[‚users_id‘];

$sql = „SELECT * FROM bazaar_user WHERE users_id = „.“‚$users_id'“.“LIMIT 1″ ;

if($output = mysqli_query($dbc, $sql)){

if(mysqli_num_rows($output) > 0){ // if any record obtained from SELECT query

while($row = mysqli_fetch_array($output)){ //next rows outputed in while loop

$first_name = $row[‚first_name‘];

$lastname_name = $row[‚lastname_name‘];

$addresss = $row[‚addresss‘];

$city = $row[‚city‘];

$ZIPcode = $row[‚ZIPcode‘];

$email = $row[‚email‘];

<br>

<h5> Please check your contact and delivery info, these information are important for

seller of the items for correct contact and delivery! </h5>

<br>

<table>

<tr>

<td>

<input type=“text“ name=“nickname“ class=“form-control“ value=“<?php echo $email; ?>“ disabled>

<br>

</td>

<td>

<label>First name:</label>

<input type=“text“ name=“first_name“ class=“form-control“ value=“<?php echo $first_name; ?>“ disabled>

<br>

</td>

<td>

<input type=“text“ name=“lastname_name“ class=“form-control“ value=“<?php echo $lastname_name; ?>“ disabled>

<br>

</td>

<tr>

</tr>

<label>Adress in form – Street Nr.:</label>

<input type=“text“ name=“addresss“ class=“form-control“ value=“<?php echo $addresss; ?>“ disabled>

<br>

</td>

<tr>

</tr>

<input type=“text“ name=“city“ class=“form-control“ value=“<?php echo $city; ?>“ disabled>

<br>

</td>

<tr>

</tr>

<label>ZIP code in form XXXXX:</label>

<input type=“text“ name=“ZIPcode“ class=“form-control“ value=“<?php echo $ZIPcode; ?>“ disabled>

</td>

</tr>

</table>

<br>

<h5> If any of displayed info need correction, please visit your profile page <a href=“editprofile.php“><u>here</u>. </a></h5>

</div>

<?php

}

// Free result set

mysqli_free_result($output);

} else{

echo „Error while reading data.“; // if no records in table

}

} else{

echo „ERROR: Could not able to execute $sql. “ . mysqli_error($dbc); // if database query problem

};

// Close connection

mysqli_close($dbc);

<br>

</h4>

<h5> For confirmation of buy select YES and click on red button bellow:</h5>

<center><button type=“submit“ name=“submit“ class=“btn btn-danger btn-bg“> I confirm the purchase with the obligation to pay </button> </center>

</form>

</div>

<a class=“navbar-brand“ href=“https://cdesigner.eu“> Visit us on CDesigner.eu </a>

</div>

</body>

</html>

Cart page generate GETable link to script removefromcart.php to enable remove item from cart. This is done by reverting cart_number filed of appropriate item from number equal to buyers users_id to zero. User is befor removing item also informed about that item is now visible for other portal user for buy. And second decision must not be available, because item will add another user to a cart.

removefromcart.php script

Content of our supplementary removal script follows here:

<!– **************************************************************** –>

<!– PHP „self“ code GET request for remove from cart –>

<!– **************************************************************** –>

<!– Vrsion: 1.0 Date: 2.11.2020 by CDesigner.eu –>

<!– **************************************************************** –>

<?php // leading part of page for simple header securing and basic variable setup

require_once(‚appvars.php‘); // including variables for database

session_start(); // start the session – must be added on all pages for session variable accessing

// solution using SESSIONS with COOKIES for longer (30days) login persistency

if(!isset($_SESSION[‚users_id‘])) { // if session is no more active

if(isset($_COOKIE[‚users_id‘]) && isset($_COOKIE[‚username‘])) { // but cookie is set then renew session variables along them

$_SESSION[‚users_id‘] = $_COOKIE[‚users_id‘];

$_SESSION[‚username‘] = $_COOKIE[‚username‘];

$_SESSION[‚user_role‘] = $_COOKIE[‚user_role‘]; // added for role

}

// two variables for message and styling of the mesage with bootstrap

$msg = “;

$msgClass = “;

// default values of auxiliary variables

<!– ******************************************* –>

<!– script for removing item from cart –>

<!– ******************************************* –>

<!– obtain GET data from cart.php and trough –>

<!– POST submit remove goods from cart by –>

<!– seting cart_number filed to 0 – notasigned –>

<!– to any user –>

<!– ******************************************* –>

<!DOCTYPE html>

<html>

<head>

<title> Bazaar remove from cart – remove script </title>

</head>

<body>

<a class=“navbar-brand“ href=“cart.php“>Return to your shopping car</a>

<a class=“navbar-brand“ href=“index.php“> –> return to main shop page</a>

</div>

</nav>

<?php if($msg != “): ?> <!– alert showing part –>

<?php endif; ?>

<h4>Confirmation of removal item from cart.</h4>

<br>

<br>

<?php // code for GET info about what to remove and submit removing approval

if(isset($_GET[‚cart_number‘]) && isset($_GET[‚item_id‘]) && isset($_GET[‚name_of_item‘]) ){

// take a data from GET link generated by adminscript

$cart_number = htmlspecialchars($_GET[‚cart_number‘]);

$item_id = htmlspecialchars($_GET[‚item_id‘]);

$name_of_item = htmlspecialchars($_GET[‚name_of_item‘]);

} else if (isset($_POST[‚cart_number‘]) && isset($_POST[‚item_id‘]) && isset($_POST[‚name_of_item‘])) { //grab score from POST – different behavior for removal

$cart_number = htmlspecialchars($_POST[‚cart_number‘]);

$item_id = htmlspecialchars($_POST[‚item_id‘]);

$name_of_item = htmlspecialchars($_POST[‚name_of_item‘]);

} else { //error info message

echo ‚<p class=“alert alert-danger“> Please specify any cart item for removal. </p>‘;

};

if(isset($_POST[‚submit‘])){

if($_POST[‚confirm‘] == ‚Yes‘ ){ // delete appropriate score post with imagescreenshot

//delete the screenshotimage from the

$cart_number = htmlspecialchars($_POST[‚cart_number‘]);

$item_id = htmlspecialchars($_POST[‚item_id‘]);

$name_of_item = htmlspecialchars($_POST[‚name_of_item‘]);

// conect to the database

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PW, DB_NAME);

//Delete score data from the database

$sql = „UPDATE bazaar_item SET cart_number = ‚0‘ WHERE item_id = $item_id LIMIT 1“;

// execute SQL

mysqli_query($dbc, $sql);

// close database connection

mysqli_close($dbc);

// confirm executed command

echo ‚<p> The item ‚ . $name_of_item . ‚ with id<strong>‘ . $item_id . ‚</strong> was sucesfully removed from your cart and now is available in listening for sell

for another user. </p>‘;

} else {

echo ‚<p class=“alert alert-danger“ > The selected item cannot be removed. </p>‘;

}

} else if (isset($cart_number) && isset($item_id) && isset($name_of_item) ) {

echo ‚<h5>Are you sure to remove ‚ . $name_of_item . ‚ from your cart? Item will be set for sell listening and can be bought by another user.</h5>‘;

// show short describtion of score for deletion

echo ‚<p> <strong> item_id: </strong> ‚ . $item_id . ‚<br> <strong> item name is: </strong>‘ . $name_of_item .

‚</p>‘;

//generating removing confirmation form

echo ‚<form method=“POST“ action=“removefromcart.php“>‘; //not self but direct this script removecategory.php – we dont want include any GET data tahat previously send

echo ‚<input type=“radio“ name=“confirm“ value=“Yes“ /> Yes ‚;

echo ‚<input type=“radio“ name=“confirm“ value=“No“ checked=“checked“ /> No <br><br>‘;

echo ‚<input type=“hidden“ name=“cart_number“ value=“‚.$cart_number.'“ />‘;

echo ‚<input type=“hidden“ name=“item_id“ value=“‚.$item_id.'“ />‘;

echo ‚<input type=“hidden“ name=“name_of_item“ value=“‚.$name_of_item.'“ />‘;

echo ‚<input type=“submit“ class=“btn btn-danger“ value=“submit“ name=“submit“ />‘;

echo ‚</form>‘;

};

echo ‚<br><br>‘;

echo ‚<p> <a href = „cart.php“> <&lt Back to your cart. </a></p>‘;

</div>

<a class=“navbar-brand“ href=“https://cdesigner.eu“> Visit us on CDesigner.eu </a>

</div>

</body>

</html>

Conclusion and final thoughts

Our cart solution implement simple way how to manage users items for buy. For further improvements is important mark sold items for admin removal or better mark them for removal by automated script after some time. Way how to do this, is mark item after succesfull buy comitt them from users_id to -1 (cart_number filed of that item in bazaar_item table). This mean item was sold and after some time they must be removed from portal.

Full aplcation code for further study can be obtained from github here.

Bazaar – php example code – part 7 – limiting user access and diferent page content display

Article deeper focus on mechanism how to use session variables created for loged in user for diferentiating page display. This mechanism relays on login features described in article part 6. Together make reusable solution for another projects with need in restricting access and diferent page content display for diferent categories of users.

Diferent content display – how to?

In many cases is important to display content of the page diferently for diferent types of users. Page for anonymous user will not display ability for editing user profiles or only loged in user can sell or buy listed items.

First part of all pages restricting access to them contains initialization session function call and reading info from session. If session is not set up, then look at data stored in cookies. If cookies contain valid information about loged in users, then session inforation is per page restored by their content. If not, page display content as for anonymous user.

This code looks like this

require_once(‚appvars.php‘); // including variables for database

// two variables for message and styling of the mesage with bootstrap

session_start(); // start the session – must be added on all pages for session variable accessing

// solution using SESSIONS with COOKIES for longer (30days) login persistency

if(!isset($_SESSION[‚users_id‘])) { // if session is no more active

if(isset($_COOKIE[‚users_id‘]) && isset($_COOKIE[‚username‘])) { // but cookie is set then renew session variables along them

$_SESSION[‚users_id‘] = $_COOKIE[‚users_id‘];

$_SESSION[‚username‘] = $_COOKIE[‚username‘];

$_SESSION[‚user_role‘] = $_COOKIE[‚user_role‘]; // added for role

}

Diferent page content display

For diferent page display, we request for existence one fo session variable. If present, user is loged in, if not alternatve part of page code must be shown.

<!– *************************************************** –>

<!– HTML part available after succesfull login as user –>

<!– *************************************************** –>

<?php if(isset($_SESSION[‚users_id‘]) ) { //if user is loged with users_id then editprofile form is available?>

… part of page code shown if user loged in …

<!– ***************************************** –>

<!– HTML part displayed for unloged user –>

<!– ***************************************** –>

<?php } else { // else if user is not loged then form will noot be diplayed?>

<br>

<br>

<h4>For listening items for sell you must be loged in <a class=“navbar-brand“ href=“login.php“> here. </a></h4>

<br>

<?php } ?>

Main page menu variable content display

Main menu is another example of part fo adaptive dsiplay relaying on category of loged in user.

Next code display way how to display their content.

<body>

<?php // generate menu if user is loged in or not

// old solution with cookies if(isset($_COOKIE[‚username‘])) { // loged in user

if(isset($_SESSION[‚username‘])) { // loged in user

echo ‚<a class=“navbar-brand“ href=“index.php“>Bazaar – best items for a best prices!</a>‘;

echo ‚<a class=“navbar-brand“ href=“editprofile.php“> Edit profile </a>‘;

echo ‚<a class=“navbar-brand“ href=“logout.php“> Logout ‚ .$_SESSION[‚username‘] .'</a>‘;

if(isset($_SESSION[‚user_role‘])==’admin‘) {

echo ‚<a class=“navbar-brand“ href=“admin.php“> Manage your page </a>‘;

};

require_once(‚sell_icon.php‘); // graphic menu item for selling your items – we focus on this two items in next articles from tihis series

require_once(‚cart_icon.php‘); // small cart icon in menu

} else { // visitor without login

echo ‚<a class=“navbar-brand“ href=“login.php“> Log In </a>‘;

echo ‚<a class=“navbar-brand“ href=“signup.php“> Sign Up for better membership! </a>‘;

echo ‚<a class=“navbar-brand“ href=“index.php“>Bazaar – best items for a best prices!</a>‘;

}

</div>

</nav>

Different display of content shows following pictures on example of admin page.

Display of admin page for user with low priviledges – relogin as admin requested.

Conclusions and further thoughts

We described ways how to display diferent content of the pages for diferent categories of users. Or mechanism use existence of sesion variables of loged user for making decision of which part of page is visible.

Inplementation of this features in whole project can be wisible on our github account here.

Bazaar – php example code – part 6 – user login with SESSIONS and COOKIES

This new year article will focus on using $_SESSION and $_COOKIE variables in proces on login user into a application. As first part of our next topics focused on user validation and diferentiation app behavior we will take closer look on signing up and login of page user.

Login mechanism in closer look

In our previeous application of mailer, we used for restricting access in to a specific page only HTTP header authentication mechanism. This approach is very simple but not scale well in larger sites with different pages with partialy or complet access restrictions.

New approach relays on login ability created by login.php script. Login script obtain user login credentials, compare it with those stored in database (passwords can not be stored as plain text, but we store only sha1 hashes and make comparisn with hashes together for deciding about corect or incorrect login).

After succesfull login $_SESSION variables are set. For better persistency there is made combination with $_ COOKIES variable. COOKIES are stored in local users browser and are available only if they are enabled by user, that must be keept in mind.

In all pages are SESSION started in first parts of php code and from COOKIES restore sessions among all pages where login restrictions must be made. In our next article, we take a closer look how limiting or difrentiating page looks for different category of users introduced with category of users database field.

For logout, there is available logout script with mechanism for invalidatin COOKIES and clearing SESSIONS variables.

Creating new users with sign up script

Our application need mechanism for subscribing new users for deeper access in pages for submitting items for sell ore more specific page available only for admin role of user – adminpage.

New user provide username, e-mail and type 2x password. Username must be unique and not used by another user. This mechanism is implemented in sql query but in our approach not in UNIQUE restriction in database field.

After succesfull login credentials creation, user can log in with existing login script.

Now we can take closer look at mentionied pages.

Sign Up script

User provide from sign up form username, e-mail and password. If username is unique (no unique e-mail is needed, because we can expect different logins of seler for different account with the same e-mail) user login credentials are added and user with role „user“ is introduced into bazar_user database table.

User role grant ability to buy and sell items, but not provide management ability mark items as eligible for visibility on title page of bazaar.

Listening of our script follows.

<!– ***************************************************************** –>

<!– PHP „self“ code handling sign up for membership on the bazaar app –>

<!– ***************************************************************** –>

<!– Vrsion: 1.0 Date: 24.10-24.10.2020 by CDesigner.eu –>

<!– ***************************************************************** –>

<?php

require_once(‚appvars.php‘); // including variables for database

// two variables for message and styling of the mesage with bootstrap

$msg = “;

$msgClass = “;

$u_name = “;

$usr_passwd = “;

/* Attempt MySQL server connection. */

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PW, DB_NAME);

if(isset($_POST[‚submit‘])) {

// obtaining submitted data from POST

$u_name = htmlspecialchars($_POST[‚u_name‘]);

$u_pass_1 = htmlspecialchars($_POST[‚u_pass_1‘]);

$u_pass_2 = htmlspecialchars($_POST[‚u_pass_2‘]);

$email = htmlspecialchars($_POST[‚email‘]);

if(!empty($u_name) && !empty($email) && !empty($u_pass_1) && !empty($u_pass_2) && ($u_pass_1 = $u_pass_2)) {

// make sure that username is available and is not registered for someone else

$sql = „SELECT * FROM bazaar_user WHERE username = „.“‚$u_name'“ ;

$data = mysqli_query($dbc, $sql);

if(mysqli_num_rows($data) == 0) {

// username is unique and have not been used by any previous user

$usr_passwd_sha1 = sha1($u_pass_2);

$sql = „INSERT INTO bazaar_user (username, pass_word, write_date, email, nickname)

VALUES (‚$u_name‘, ‚$usr_passwd_sha1‘ , now(), ‚$email‘,’$u_name‘)“; // by default nickname and username are the same, next user can change

if(mysqli_query($dbc, $sql)){

$msg = ‚ Your new account has been created successfully.

You are now ready to <a href=“login.php“>log in</a>‘;

$msgClass = ‚alert-success‘;

} else{

echo „ERROR: Could not able to execute $sql. “ . mysqli_error($dbc); // if database query problem

}

//success confirmation for registered user

// Free result set

mysqli_free_result($data);

// Close connection

//exit(); if used blank page will be displayed without any other redirecting

} else { // an account already exists for this username, so display an error message

$msg = ‚ An account for submitted username already exsts. Please use different username …‘;

$msgClass = ‚alert-danger‘;

}

} else {

$msg = ‚ Your must enter all of the required data, including contact e-mail address.‘;

$msgClass = ‚alert-danger‘;

}

// Close connection

mysqli_close($dbc);

<!– **************************************** –>

<!– HTML code containing Form for submitting –>

<!– **************************************** –>

<!DOCTYPE html>

<html>

<head>

<title> Bazaar signup page </title>

</head>

<body>

<a class=“navbar-brand“ href=“index.php“>Bazaar – Signup for submitting/ buying your items</a>

</div>

</nav>

<?php if($msg != “): ?>

<br>

<?php endif; ?>

<br>

<br>

<legend> Please register for Bazaar membership <legend>

<label>Username:</label>

<input type=“text“ onfocus=“this.value='<?php echo isset($_POST[‚u_name‘]) ? $u_name : “; ?>'“ name=“u_name“ class=“form-control“ value=“<?php echo isset($_POST[‚u_name‘]) ? $u_name : ‚Login name‘; ?>“>

<input type=“text“ onfocus=“this.value='<?php echo isset($_POST[‚email‘]) ? $email : “; ?>'“ name=“email“ class=“form-control“ value=“<?php echo isset($_POST[‚email‘]) ? $email : ‚@‘; ?>“>

<label>Password:</label>

<input type=“password“ onfocus=“this.value='<?php echo isset($_POST[‚u_pass_1‘]) ? “ : “; ?>'“ name=“u_pass_1″ class=“form-control“ value=“<?php echo isset($_POST[‚u_pass_1‘]) ? “ : “; ?>“>

<label>Password:</label>

<input type=“password“ onfocus=“this.value='<?php echo isset($_POST[‚u_pass_2‘]) ? “ : “; ?>'“ name=“u_pass_2″ class=“form-control“ value=“<?php echo isset($_POST[‚u_pass_2‘]) ? “ : “; ?>“>

</div>

<br>

</form>

</div>

<a class=“navbar-brand“ href=“https://cdesigner.eu“> Visit us on CDesigner.eu </a>

</div>

</body>

</html>

Front look at signup page follows.

Login page

Code for loginpage take place only if user is not allready loged in. In this option is not set !isset($_SESSION[‚users_id‘]) . After verfication of login credentials SESSION variables and COOKIES are set for loged in user. Also loed in user is redirected on index.php main page as it contains next code.

<!– ***************************************************************** –>

<!– PHP „self“ code handling login into the bazaar app –>

<!– ***************************************************************** –>

<!– Vrsion: 1.0 Date: 11.10-24.10.2020 by CDesigner.eu –>

<!– ***************************************************************** –>

<?php

require_once(‚appvars.php‘); // including variables for database

session_start(); // start the session

// two variables for message and styling of the mesage with bootstrap

$msg = “;

$msgClass = “;

$usr_username = “;

$usr_passwd = “;

//get info that user is loged in, if not try it looking at cookies

//if(!isset($_COOKIE[‚s‘])) { old solution with cookies

if(!isset($_SESSION[‚users_id‘])) { //new with session variables

if(isset($_POST[‚submit‘])) {

/* Attempt MySQL server connection. */

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PW, DB_NAME);

// accessing user entered login data

$usr_username = htmlspecialchars($_POST[‚u_name‘]);

$usr_passwd = htmlspecialchars($_POST[‚u_pass‘]);

if(!empty($usr_username) && !empty($usr_passwd)) {

// try lookup user database

$usr_passwd_SHA = sha1($usr_passwd);

$sql = „SELECT users_id, username, user_role FROM bazaar_user WHERE username = „.“‚$usr_username'“. “ AND pass_word = „.“‚$usr_passwd_SHA'“ ;

// debug output echo $usr_username;

// echo $usr_passwd;

//echo $usr_passwd_SHA;

$data = mysqli_query($dbc, $sql);

if(mysqli_num_rows($data) == 1) {

// login is ok, set user ID and username cookies and redirect to the homepage

$row = mysqli_fetch_array($data);

//setcookie(‚users_id‘, $row[‚users_id‘]); old solution with cookies

//setcookie(‚username‘, $row[‚username‘]);

$_SESSION[‚users_id‘] = $row[‚users_id‘]; // sloution with sessions

$_SESSION[‚username‘] = $row[‚username‘];

$_SESSION[‚user_role‘] = $row[‚user_role‘]; // added user_role session variable

// new cookies for login persistency that expires after 30 days without logout combination SESSION with COOKIES is awailable

setcookie(‚users_id‘, $row[‚users_id‘], time()+(60+60*24*30));

setcookie(‚username‘, $row[‚username‘], time()+(60+60*24*30));

setcookie(‚user_role‘, $row[‚user_role‘], time()+(60+60*24*30)); // cookie for user_role of loged in user added

$home_url = ‚http://‘. $_SERVER[‚HTTP_HOST‘] . dirname($_SERVER[‚PHP_SELF‘]) . ‚/index.php‘;

header(‚Location:‘. $home_url);

// Free result set

mysqli_free_result($data);

// Close connection

mysqli_close($dbc);

} else {

// urename/ password are incorrect – error meesage is displayed

$msg = „Incorrect username or password. Login denied! „;

$msgClass = ‚alert-danger‘;

}

} else {

// username/ password were not entered – display error message

$msg = „Sorry, you must eneter username and password to log in. „;

$msgClass = ‚alert-danger‘;

}

<!– **************************************** –>

<!– HTML code containing Form for submitting –>

<!– **************************************** –>

<!DOCTYPE html>

<html>

<head>

<title> Bazaar login page </title>

</head>

<body>

<a class=“navbar-brand“ href=“index.php“>Bazaar – Login page</a>

</div>

</nav>

<?php if($msg != “): ?>

<br>

<?php endif; ?>

<?php

//if(empty($_COOKIE[‚users_id‘])) { solution with cookies

if(empty($_SESSION[‚users_id‘])) { // solution with sessions

// only show for if session with name users_id does not exist

//echo ‚ <br> ‚;

//echo ‚<p class=“alert alert-danger“>‘ . $msg . ‚</p>‘;

<br>

<br>

<label>Username:</label>

<input type=“text“ onfocus=“this.value='<?php echo isset($_POST[‚u_name‘]) ? “ : “; ?>'“ name=“u_name“ class=“form-control“ value=“<?php echo isset($_POST[‚u_name‘]) ? ‚Please reenter‘ : ‚Login name‘; ?>“>

<label>Password:</label>

<input type=“password“ onfocus=“this.value='<?php echo isset($_POST[‚u_pass‘]) ? “ : “; ?>'“ name=“u_pass“ class=“form-control“ value=“<?php echo isset($_POST[‚u_pass‘]) ? ‚Please reenter‘ : ‚Login name‘; ?>“>

</div>

<br>

</form>

<?php } else {

// successfull login

// cookie solution echo ‚<p class=“alert alert-success“> You are loged in as ‚ . $_COOKIE[‚username‘]. ‚</p>‘;

echo ‚<br>‘;

echo ‚<p class=“alert alert-success“> You are loged in as <em>‘ . $_SESSION[‚username‘]. ‚</em></p>‘; // session solution

echo ‚<p class=“alert alert-success“> If you will logout or login with anither credentials, please first <a href=“logout.php“>logout!. </a></p>‘;

}

</div>

<a class=“navbar-brand“ href=“https://cdesigner.eu“> Visit us on CDesigner.eu </a>

</div>

</body>

</html>

Next pictures display output on page after difrenet state of login process.

Error messaging after unsuccesfull login

Logout script

Last and shortest code page is logout page. After hitting link for logout, user sessions and cokkies are inmediatly destroyed and user is loged out. Without logout with cookies enabled, user is loged in in browser for 30 days. If brower disables cookies, user is loged in only if sessions are active up to closing browser windows.

Full code follows:

<!– ***************************************************************** –>

<!– PHP „self“ code handling logout procedure into the bazaar app –>

<!– ***************************************************************** –>

<!– Vrsion: 1.0 Date: 24.10-24.10.2020 by CDesigner.eu –>

<!– ***************************************************************** –>

<?php

require_once(‚appvars.php‘); // including variables for database

// part for SESSION solution for login persistence and its ending

//even when logging out you have to first start the session in order to access the session variables

session_start();

if(isset($_SESSION[‚users_id‘])) {

$_SESSION = array(); // deleting session vars

};

// if session cookie exists, then delete it

if(isset($_COOKIE[session_name()])) {

setcookie(‚session_name()‘,“,time() – 3600);

};

// Destroy session

session_destroy();

// logout user by deleting cookie – for COOKIES persistence solution

/* if(isset($_COOKIE[‚users_id‘])) {

setcookie(‚user_id‘,“,time() – 3600);

setcookie(‚username‘,“,time() – 3600);

echo „deleted cookies“;

}; */

// for our final solution SESSIONS+ longer login persistency with COOKIES must be also cokies deleted

setcookie(‚users_id‘, $row[‚users_id‘], time()-3600);

setcookie(‚username‘, $row[‚username‘], time()-3600);

setcookie(‚user_role‘, $row[‚user_role‘], time()-3600); // added deletion of user_role cookie – after altering table for user_role

// redirect to homepage in logout state

$home_url = ‚http://‘. $_SERVER[‚HTTP_HOST‘] . dirname($_SERVER[‚PHP_SELF‘]) . ‚/index.php‘;

header(‚Location:‘. $home_url);

Conclusion and final thoughts

In this article we take focus on way how to grant user limited access in to a page resources. This solution uses sessions with suporting role by cookies.

In our next article we will focus how to use session log in information for diferentiating page display for diferent roles of page users (anonymous = unloged, user-s and admin-s).

Full code in as is state can be obtained from github here.

Bazaar – php example code – part 5 – admin page

Article focus on way how to create site admin page. In our first approach we focus only on content of the page, limiting access only for admin will be described in further articles.

Expectation for site admin page

Admin page is accessible only for specific user category. This category is defined by user_role as admin. Restricting access and iferent display of this page for diferent category of users will be explained in further articles.

With admin page we can publish/ unpublish or remove items for sell. Second functionality created up to ime of vriting of this article is category management.

Management operation is maintained by links leading to operational scripts as is removecategory.php or removeitem.php.

Removeitem php script is much moore interesting because display three options with conformation of operation. After succesfull submiting one of three posible sql is executed along content inserted in $oprtion variable.

Visual look of admin page

Visual look of admin page is as follows:

After implementing login functionality, there will be two other output of this page, one for anonymous user and one for common user role.

admin page for common user will request relogin with elevated priviledge

Implementation of desired functionality

Generating table for item and for category is most common, we will discuss these parts in previews articles. But we wil take a closer look at code of removeitem.php, with new option datalist functionality for selection among three functionalities: publishing, unpublishing and removing item by site admin.

All selection lead to different sql script, first two manipulate with contnt of field published on bazaar_item page. If this value is zero item si not displayed in listenings for users in index page. After seting on 1, items are dsiplayed.

Removing item is LIMITed on only one matching items for further security. Also one yes selection during submitting these operations are required.

Full code of removeitem.php script will follow:

<!– ***************************************************************** –>

<!– PHP „self“ code GET request for remove andable or disable product item –>

<!-***************************************************************** –>

<!– Vrsion: 1.0 Date: 18.10.2020 by CDesigner.eu –>

<!– **************************************************************** –>

<?php // leading part of page for simple header securing and basic variable setup

require_once(‚appvars.php‘); // including variables for database

session_start(); // start the session – must be added on all pages for session variable accessing

// solution using SESSIONS with COOKIES for longer (30days) login persistency

if(!isset($_SESSION[‚users_id‘])) { // if session is no more active

if(isset($_COOKIE[‚users_id‘]) && isset($_COOKIE[‚username‘])) { // but cookie is set then renew session variables along them

$_SESSION[‚users_id‘] = $_COOKIE[‚users_id‘];

$_SESSION[‚username‘] = $_COOKIE[‚username‘];

}

// two variables for message and styling of the mesage with bootstrap

$msg = “;

$msgClass = “;

// default values of auxiliary variables

<!– ******************************************* –>

<!– script for appropriate scode removal –>

<!– ******************************************* –>

<!– obtain GET data from admin.php and trough –>

<!– POST submit remove data from database –>

<!– ******************************************* –>

<!DOCTYPE html>

<html>

<head>

<title> Bazaar score – publish/unpublish/remove item script </title>

</head>

<body>

<a class=“navbar-brand“ href=“admin.php“> –> Bazaar admin page</a>

<a class=“navbar-brand“ href=“index.php“> –> return to main shop page</a>

</div>

</nav>

<?php if($msg != “): ?> <!– alert showing part –>

<?php endif; ?>

<h4>Please select what you will do.</h4>

<br>

<br>

<?php // code for GET info about what to remove and submit removing approval

/* structure of generated link on admin.php page for further reference

echo ‚<td colspan=“1″><a id=“DEL“ href=“removeitem.php?item_id=‘.$row[‚item_id‘] . ‚&name_od_item=‘

. $row[‚name_of_item‘] . ‚&price_eur=‘. $row[‚price_eur‘] .

‚&published=‘. $row[‚published‘] . ‚&screenshot1=‘. $row[‚screenshot1‘] .

‚&screenshot2=‘. $row[‚screenshot2‘] . ‚&screenshot3=‘. $row[‚screenshot3‘] . ‚“> >>Publish/UnPub./Remove </a></td></tr>‘;

if(isset($_GET[‚item_id‘]) && isset($_GET[‚name_of_item‘]) && isset($_GET[‚price_eur‘]) && isset($_GET[‚published‘]) && isset($_GET[‚screenshot1‘])){

// take a data from GET link generated by adminscript

$item_id = htmlspecialchars($_GET[‚item_id‘]);

$name_of_item = htmlspecialchars($_GET[‚name_of_item‘]);

$price_eur = htmlspecialchars($_GET[‚price_eur‘]);

$published = htmlspecialchars($_GET[‚published‘]);

$screenshot1 = htmlspecialchars($_GET[‚screenshot1‘]);

$screenshot2 = htmlspecialchars($_GET[‚screenshot2‘]);

$screenshot3 = htmlspecialchars($_GET[‚screenshot3‘]);

} else if (isset($_POST[‚item_id‘]) && isset($_POST[‚name_of_item‘]) && isset($_POST[‚price_eur‘]) && isset($_POST[‚published‘]) && isset($_POST[‚screenshot1‘])) { //grab score from POST – different behavior for removal

$item_id = htmlspecialchars($_POST[‚item_id‘]);

$name_of_item = htmlspecialchars($_POST[‚name_of_item‘]);

$price_eur = htmlspecialchars($_POST[‚price_eur‘]);

$published = htmlspecialchars($_POST[‚published‘]);

$screenshot1 = htmlspecialchars($_POST[‚screenshot1‘]);

$screenshot2 = htmlspecialchars($_POST[‚screenshot2‘]);

$screenshot3 = htmlspecialchars($_POST[‚screenshot3‘]);

} else { //error info message

echo ‚<p class=“alert alert-danger“> Please specify any category for removal. </p>‘;

};

if(isset($_POST[‚submit‘])){

if($_POST[‚confirm‘] == ‚Yes‘ ){ // delete appropriate score post with imagescreenshot

//read all data from $_POST array

$item_id = htmlspecialchars($_POST[‚item_id‘]);

$name_of_item = htmlspecialchars($_POST[‚name_of_item‘]);

$price_eur = htmlspecialchars($_POST[‚price_eur‘]);

$published = htmlspecialchars($_POST[‚published‘]);

$screenshot1 = htmlspecialchars($_POST[‚screenshot1‘]);

$screenshot2 = htmlspecialchars($_POST[‚screenshot2‘]);

$screenshot3 = htmlspecialchars($_POST[‚screenshot3‘]);

$operation = htmlspecialchars($_POST[‚operation‘]);

// conect to the database

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PW, DB_NAME);

//create sql query along selected operation

switch ($operation) {

case „publish„:

$sql = „UPDATE bazaar_item SET published = ‚1‘ WHERE item_id = $item_id LIMIT 1„;

// execute SQL

mysqli_query($dbc, $sql);

// confirm executed command

echo ‚<p> The item <strong>‘ . $name_of_item . ‚</strong> with id <strong>‘ . $item_id . ‚</strong> was succesfully published. </p>‘;

break;

case „unpublish„:

$sql = „UPDATE bazaar_item SET published = ‚0‘ WHERE item_id = $item_id LIMIT 1„;

// execute SQL

mysqli_query($dbc, $sql);

// confirm executed command

echo ‚<p> The item <strong>‘ . $name_of_item . ‚</strong> with id <strong>‘ . $item_id . ‚</strong> was succesfully unpublished. </p>‘;

break;

case „delete„:

$sql = „DELETE FROM bazaar_item WHERE item_id = $item_id LIMIT 1″;

// execute SQL

mysqli_query($dbc, $sql);

// confirm executed command

echo ‚<p> The item <strong>‘ . $name_of_item . ‚</strong> with id <strong>‘ . $item_id . ‚</strong> was succesfully deleted from listening on bazaar. </p>‘;

break;

}

// close database connection

mysqli_close($dbc);

} else {

echo ‚<p class=“alert alert-danger“ > The selected operation cannot be performed. </p>‘;

}

} else if (isset($item_id) && isset($price_eur) && isset($name_of_item) && isset($published) && isset($screenshot1) ) {

echo ‚<h5>Are you sure perform selected operation with bazaar item? </h5>‘;

// show short describtion of score for deletion

$image_location = IMAGE_PATH.$screenshot1;

echo ‚<p> <strong> Item_id: </strong> ‚ . $item_id . ‚<br> <strong> Name: </strong>‘ . $name_of_item .

‚</p>‘;

echo “ <img src=\“$image_location\“ alt=\“ score image \“ height=\“150\“> „;

//generating removing/ publishing/ unpublishing confirmation form

echo ‚<form method=“POST“ action=“removeitem.php“>‚; //not self but direct this script removecategory.php – we dont want include any GET data tahat previously send

echo ‚<h4> Please select your operation </h4>‘;

echo ‚<input list=“operation“ name=“operation“ placeholder=“select“ >‘;

echo ‚<datalist id=“operation“>‘;

echo ‚<option value=“publish“>‘;

echo ‚<option value=“unpublish“>‘;

echo ‚<option value=“delete“>‘;

echo ‚</datalist>‘;

echo ‚<br><br>‘;

echo ‚<input type=“radio“ name=“confirm“ value=“Yes“ /> Yes ‚;

echo ‚<input type=“radio“ name=“confirm“ value=“No“ checked=“checked“ /> No <br><br>‘;

echo ‚<input type=“hidden“ name=“item_id“ value=“‚.$item_id.'“ />‘;

echo ‚<input type=“hidden“ name=“price_eur“ value=“‚.$price_eur.'“ />‘;

echo ‚<input type=“hidden“ name=“name_of_item“ value=“‚.$name_of_item.'“ />‘;

echo ‚<input type=“hidden“ name=“published“ value=“‚.$published.'“ />‘;

echo ‚<input type=“hidden“ name=“screenshot1″ value=“‚.$screenshot1.'“ />‘;

echo ‚<input type=“hidden“ name=“screenshot2″ value=“‚.$screenshot2.'“ />‘;

echo ‚<input type=“hidden“ name=“screenshot3″ value=“‚.$screenshot3.'“ />‘;

echo ‚<input type=“submit“ class=“btn btn-danger“ value=“submit“ name=“submit“ />‘;

echo ‚</form>‚;

};

echo ‚<br><br>‘;

echo ‚<p> <a href = „admin.php“> <&lt Back to admin page. </a></p>‘;

</div>

<a class=“navbar-brand“ href=“https://cdesigner.eu“> Visit us on CDesigner.eu </a>

</div>

</body>

</html>

Visual look of confirmation part with operation selection is displayed here:

rmoveitem.php script confirmation dialog with option

Conclusion and further thoughts

Our admin page contains baseline for page administration, in next times we can add some parts for admin or moderation if needed.

Full code of bazaar app can be obtained from github here.

Bazaar – php example code – part 4 – Selling item script

Our special Christmass article focus on listening item for sell on bazaar page. Data are obtained from registered user, inserted into a database and because default published filed in bazaar_item table is false, waiting for admin approval. In final version, this page is available only for registered user.

Expectation from sellingitem script

In final applicaton, selling page is available only for common registered user. User must be able do these things:

decribe name and price for selling item
add up to three different photos
select category with subcategory
provide any further describtion for selling item
item is not listed for sell untip approval of admin of the page

After sucessful post for sell, short describtion about adding document to a database is generated in pottom part of form.

After finalizing other main parts of app responsible for user management, we will add column for marking selling by users_id for difrerentiating of the seller. When someone decide to buy any their item, seller must be notified about buy and must fullfil item delivery.

Visual look of the page

Sell item page consist from sell form and list of published item for sell. In the middle part, ist optionaly after succesfull post displayed short info about user action.

Implementation of functionality

Main part of page consist form form part. In this part is insered script for generating available category list obtained from bazaar_category table.

Separate par enable selecting up to three files fortransfer. First screenshot of product is required and can not be ommited. Other two are optional as you can see. Separate Javascript code is responsible for listening file path after selecting them into a dialog field.

Next output show contetnt of the form:

<form enctype=„multipart/form-data“ method=“post“ action=“<?php echo $_SERVER[‚PHP_SELF‘]; ?>“> // because data file transfer enctype must be defined in form tag!!!

<label>* Please provide name of selling item:</label>

<input type=“text“ onfocus=“this.value='<?php echo isset($_POST[‚name_of_item‘]) ? $name_of_item : “; ?>'“ name=“name_of_item“ class=“form-control“ value=“<?php echo isset($_POST[‚name_of_item‘]) ? $name_of_item : ‚Name for product‘; ?>“>

<label>* Please provide price for item in €:</label>

<input type=“text“ onfocus=“this.value='<?php echo isset($_POST[‚price_eur‘]) ? $price_eur : “; ?>'“ name=“price_eur“ class=“form-control“ value=“<?php echo isset($_POST[‚price_eur‘]) ? $price_eur : ‚Price in €‘; ?>“>

<!– slection of category and subcategory –>

<label>* Select main category-subcategory for proper item listing on bazar pages:</label>

<?php // here read data from mysql bazaar_category and display existing category whre subcategory will be nested

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PW, DB_NAME);

// Check connection

if($dbc === false){

die(„ERROR: Could not connect to database. “ . mysqli_connect_error());

};

// create SELECT query for category names from database

$sql = „SELECT DISTINCT category, subcategory FROM bazaar_category ORDER BY category ASC, subcategory ASC„;

// execute sql and populate data list with existing category in database

if($output = mysqli_query($dbc, $sql)){

if(mysqli_num_rows($output) > 0){ // if any record obtained from SELECT query

while($row = mysqli_fetch_array($output)){ //next rows outputed in while loop

echo „<option value=“ . $row[‚category‘] .“-„.$row[‚subcategory‘] . „>„;

}

// Free result set

mysqli_free_result($output);

} else{

echo „There is no category in category table. Please wirite one.“; // if no records in table

}

} else{

echo „ERROR: Could not able to execute $sql. “ . mysqli_error($dbc); // if database query problem

}

// Close connection

mysqli_close($dbc);

</datalist>

<p> If no proper category-subcategory exist, please contact admin of the pages for creation them for you. </p>

<!– users_id from session obtaining – for debuging and testing is set as hidden –>

</div>

<p> In this part you can select upto 3 pictures of the product. First picture is required! </p>

<label>* Please select location of your score screenshot from drive – max 5MB!</label>

<label class=“custom-file-label1 custom-file-label“ for=“customFile“>Screenshot1 – required:</label>

</div>

<label class=“custom-file-label2 custom-file-label“ for=“customFile“>Screenshot2 – optional:</label>

</div>

<label class=“custom-file-label3 custom-file-label“ for=“customFile“>Screenshot3 – optional:</label>

</div>

$(document).ready(function(){

$(„#screenshot1“).change(function(){

//alert(„A file 1 has been selected.“);

var thefile1 = document.getElementById(‚screenshot1‘);

var fileName1 = thefile1.value;

//var fileName1 = „A file 1 has been selected.“;

$(‚.custom-file-label1‘).html(fileName1);

});

$(„#screenshot2“).change(function(){

//alert(„A file 2 has been selected.“);

var thefile2 = document.getElementById(‚screenshot2‘);

var fileName2 = thefile2.value;

//var fileName2 = „A file 2 has been selected.“;

$(‚.custom-file-label2‘).html(fileName2);

});

$(„#screenshot3“).change(function(){

//alert(„A file 3 has been selected.“);

var thefile3 = document.getElementById(‚screenshot3‘);

var fileName3 = thefile3.value;

//var fileName3 = „A file 3 has been selected.“;

$(‚.custom-file-label3‘).html(fileName3);

});

</script>

<label>* Item description:</label> <!– textera for input large text –>

<textarea id=“item_description“ onfocus=“this.value='<?php echo isset($_POST[‚item_descriptio‘]) ? $item_description : ‚Please provide description of selling item …‘; ?>'“ name=“item_description“ class=“form-control“ rows=“3″ cols=“50″><?php echo isset($_POST[‚item_description‘]) ? $item_description : ‚Description of item for sell goes here …‘; ?></textarea>

</div>

<!– div class=“form-group“>

<label>Your message for Guestbook:</label–> <!– textera for input large text –>

<!– textarea id=“postmessage“ name=“postmessage“ class=“form-control“ rows=“6″ cols=“50″><?php echo isset($_POST[‚postmessage‘]) ? $postmessage : ‚Your text goes here …‘; ?></textarea>

</div–>

<button type=“submit“ name=“reset“ class=“btn btn-info“> Reset form </button>

<!– remove comment after implementation

<button type=“submit“ name=“delete“ class=“btn btn-danger“> Delete recently posted score </button>

–>

<button type=“submit“ name=“reset“ class=“btn btn-info“> Reset form </button>

<?php //part displaying info after succesfull added subscriber into a mailinglist

if ($is_result ) {

echo „<br> <br>“;

echo “ <table class=\“table table-success\“> „;

echo “ <tr>

<td><h5> <em> Item for selll: </em> $name_of_item for $price_eur € </h5> <h5> has been succesfully added to selling list. Item will be visible

on bazaar page after admin approval. </h5> „;

$image_location = IMAGE_PATH.$screenshot1;

echo “ <img src=\“$image_location\“ alt=\“ score image \“ height=\“150\“> „;

echo “ <td> </tr> „;

echo “ </table> „;

//echo “ <input type=“text“ id=“result_field“ name=“result_field“ value=“$result“ > <br>“ ;

} ;

<br>

</form>

Part responsible for obtaining data after hitting submit button consist from:

if(filter_has_var(INPUT_POST, ‚submit‘)) {

// Data obtained from $_postmessage are assigned to local variables

$name_of_item = htmlspecialchars($_POST[‚name_of_item‘]);

$price_eur = htmlspecialchars($_POST[‚price_eur‘]);

$users_id = htmlspecialchars($_POST[‚users_id‘]);

//echo ‚users_id‘; echo $users_id;

$category_subcategory = htmlspecialchars($_POST[‚category_subcategory‘]); // must be converted to subcategory_id (*)

// separate category and subcategory with strtok() function

$words = explode(‚-‚, $category_subcategory);

$category=$words[0];

//echo $category;

//echo ‚<br>‘;

$subcategory=$words[1];

//echo $subcategory;

$screenshot1 = htmlspecialchars($_FILES[‚screenshot1‘][‚name‘]);

$screenshot2 = htmlspecialchars($_FILES[‚screenshot2‘][‚name‘]);

$screenshot3 = htmlspecialchars($_FILES[‚screenshot3‘][‚name‘]);

$item_description = htmlspecialchars($_POST[‚item_description‘]);

// (*) — conversion of category and subcategory into category%id

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PW, DB_NAME);

// Check connection

if($dbc === false){

die(„ERROR: Could not connect to database. “ . mysqli_connect_error());

};

// create SELECT query for category names from database

$sql = „SELECT subcategory_id FROM bazaar_category WHERE category = „.“‚$category'“. “ AND subcategory = „.“‚$subcategory'“ ;

// execute sql and populate data list with existing category in database

if($output = mysqli_query($dbc, $sql)){

if(mysqli_num_rows($output) > 0){ // if any record obtained from SELECT query

while($row = mysqli_fetch_array($output)){ //next rows outputed in while loop

$subcategory_id = $row[‚subcategory_id‘] ;

}

// Free result set

mysqli_free_result($output);

} else {

echo „There is no souch category-subcategory in category table. Please correct your error.“; // if no records in table

}

} else{

echo „ERROR: Could not able to execute $sql. “ . mysqli_error($dbc); // if database query problem

}

// Close connection

mysqli_close($dbc);

// Controll if all required fields was written

if(!empty($name_of_item) && !empty($price_eur) && !empty($subcategory_id) && !empty($screenshot1)) { // these item identifiers are mandatory and can not be empty

// If check passed – all needed fields are written

// Check if E-mail is valid

// move image to /images final folder from demporary download location

$target1 = IMAGE_PATH . $screenshot1;

$target2 = IMAGE_PATH . $screenshot2;

$target3 = IMAGE_PATH . $screenshot3;

// !!! Add entry to the database and redraw all score in chart list descending from highest score

// insert into databse

if (move_uploaded_file($_FILES[‚screenshot1‘][‚tmp_name‘], $target1)) {

move_uploaded_file($_FILES[‚screenshot2‘][‚tmp_name‘], $target2);

move_uploaded_file($_FILES[‚screenshot3‘][‚tmp_name‘], $target3);

// make database connection

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PW, DB_NAME);

// Check connection

if($dbc === false){

die(„ERROR: Could not connect to database. “ . mysqli_connect_error());

}

// INSERT new entry

$sql = „INSERT INTO bazaar_item (name_of_item, price_eur, subcategory_id, users_id, item_add_date, screenshot1, screenshot2, screenshot3, item_description)

VALUES (‚$name_of_item‘, $price_eur , ‚$subcategory_id‘ , ‚$users_id‘ , now(), ‚$screenshot1‘, ‚$screenshot2‘, ‚$screenshot3‘, ‚$item_description‘ )“;

//show added item true

$is_result = true;

if(mysqli_query($dbc, $sql)){

$msg = ‚New item ‚.$name_of_item. ‚ for ‚. $price_eur. ‚ € succesfully added to sell item – waiting for admin approvall.‘;

$msgClass = ‚alert-success‘;

} else {

$msg = „ERROR: Could not able to execute $sql. “ . mysqli_error($dbc);

$msgClass = ‚alert-danger‘;

}

// end connection

mysqli_close($dbc);

} else {

// Failed – if not all fields are fullfiled

$msg = ‚Please fill in all * marked contactform fields‘;

$msgClass = ‚alert-danger‘; // bootstrap format for allert message with red color

};

Conclusion and other thoughts

Our page must be updated with code displaying its content and menus diferently for loged in user or anonymous users. Next improvement is expanding/ altering code to mark added item by users_id from active session for distinguishing between submitters.

Full code of application in as is current state can be obtained for further study from here.

Bazaar – php example code – part 3 – Manage category script

Article focus on way how we populate category/ subcategory for selling items. Management page contains listing of scucessfully added fileds with removal link as option. Our project will lead from category, trough item, simple login functionality into a editprofile option with more robust user login.

Discuss managecategory.php functionality

Our managecategory.php script must enable these functionalities:

create subcategory of item with existing main category
if we creating subcategory with non existing man category, we must be able to add them along
after all succesfully added category, list of existing category/ subcategory must be displayed with link for removal appropriate category row
after preparing parts for login verification, these scripts can be viable only for user with admin role assigned by page admin

Visual content of this page along with removecategory.php script follow:

Visual look of managecategory.php script

Category romoval script confirmation dialog

Implementation of expected functionality

Our page consist from parts for obtain user category and subcategory names. Error messaging, reporting of successfull category addition into bazaar_category table are next parts of our script.

Form obtaining data from user follow next:

<label>* Set name for new subcategory:</label>

<input type=“text“ onfocus=“this.value='<?php echo isset($_POST[‚subcategory‘]) ? $subcategory : “; ?>'“ name=“subcategory“ class=“form-control“ value=“<?php echo isset($_POST[‚subcategory‘]) ? $subcategory : ‚Please provide name of new subcategory‘; ?>“>

<br>

<label>* Select main category for nesting created subcategory:</label>

<?php // here read data from mysql bazaar_category and display existing category whre subcategory will be nested

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PW, DB_NAME);

// Check connection

if($dbc === false){

die(„ERROR: Could not connect to database. “ . mysqli_connect_error());

};

// create SELECT query for category names from database

$sql = „SELECT DISTINCT category FROM bazaar_category ORDER BY category ASC„;

// execute sql and populate data list with existing category in database

if($output = mysqli_query($dbc, $sql)){

if(mysqli_num_rows($output) > 0){ // if any record obtained from SELECT query

while($row = mysqli_fetch_array($output)){ //next rows outputed in while loop

echo „<option value=“ . $row[‚category‘] . „>„;

}

// Free result set

mysqli_free_result($output);

} else{

echo „There is no category in category table. Please wirite one.“; // if no records in table

}

} else{

echo „ERROR: Could not able to execute $sql. “ . mysqli_error($dbc); // if database query problem

}

// Close connection

mysqli_close($dbc);

</datalist>

<br>

<button type=“submit“ name=“subcategorysubmit“ class=“btn btn-warning“> Create new subcategory </button>

</div>

<hr>

</form>

<?php //part displaying info after succesfull added category into a mailinglist

if ($is_result ) {

echo „<br> <br>“;

echo “ <table class=\“table table-success\“> „;

echo “ <tr>

<td><h5> <em> Category: </em> $category with subcategory $subcategory </h5> <h5> has been succesfully added to category list </h5> „;

echo “ <td> </tr> „;

echo “ </table> „;

//echo “ <input type=“text“ id=“result_field“ name=“result_field“ value=“$result“ > <br>“ ;

} ;

<br>

</form>

<?php

Listening of all items in bazaar_category table is generated by this content of script

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PW, DB_NAME);

// Check connection

if($dbc === false){

die(„ERROR: Could not connect to database – stage of article listing. “ . mysqli_connect_error());

}

// read all rows (data) from guestbook table in „test“ database

$sql = „SELECT * FROM bazaar_category ORDER BY category ASC, subcategory ASC„;

/********************************************************************/

/* Output in Table – listening all category in bazaar_category table */

/********************************************************************/

// if data properly selected from guestbook database tabele

echo „<h4>List of active categories and subcategories</h4>“;

echo „<br>“;

echo ‚ <button class=“btn btn-secondary btn-lg “ onclick=“location.href=\’admin.php\'“ type=“button“> admin page -> </button>‘;

echo „<br>“; echo „<br>“;

if($output = mysqli_query($dbc, $sql)){

if(mysqli_num_rows($output) > 0){ // if any record obtained from SELECT query

// create table output

echo „<table>“; //head of table

echo „<tr>“;

echo „<th>subcategory_id</th>“;

echo „<th>category</th>“;

echo „<th>subcategory</th>“;

echo „<th></th>“;

echo „<th>delete category</th>“;

echo „</tr>“;

while($row = mysqli_fetch_array($output)){ //next rows outputed in while loop

echo “ <div class=\“mailinglist\“> “ ;

echo „<tr>“;

echo „<td>“ . $row[‚subcategory_id‘] . „</td>“;

echo „<td>“ . $row[‚category‘] . „</td>“;

echo „<td>“ . $row[‚subcategory‘] . „</td>“;

// removal line with removing link line

echo „<td colspan=\“1\“> Manage entry: </td>“; // description on first line

echo ‚<td colspan=“1″><a id=“DEL“ href=“removecategory.php?subcategory_id=‘.$row[‚subcategory_id‘] . ‚&category=‘

. $row[‚category‘] . ‚&subcategory=‘. $row[‚subcategory‘] .'“> >> Remove </a></td></tr>‘; //construction of GETable link

// for removecategory.php input

echo „</tr>“;

echo “ </div> “ ;

}

echo „</table>“;

// Free result set

mysqli_free_result($output);

} else{

echo „There is no benchmark result in chart. Please wirite one.“; // if no records in table

}

} else{

echo „ERROR: Could not able to execute $sql. “ . mysqli_error($dbc); // if database query problem

}

// Close connection

mysqli_close($dbc);

removecategory.php script

Remove category script obtain data from GET associative array ofered from url snipet added to name of invoked page. After reading data, cerate removal confirmation form.

After selecting yes and submitting form, appropriate category/ subcategory row is removed with approrpiate sql query.

Content of the page is in following part:

<!– *************************************************************** –>

<!– PHP „self“ code GET request for remove and POST delete data –>

<!– *************************************************************** –>

<!– Vrsion: 1.0 Date: 17.10.2020 by CDesigner.eu –>

<!– *************************************************************** –>

<?php // leading part of page for simple header securing and basic variable setup

require_once(‚appvars.php‘); // including variables for database

session_start(); // start the session – must be added on all pages for session variable accessing – further description will be available in appropriate article in a row of articles focused on bazaar app

// solution using SESSIONS with COOKIES for longer (30days) login persistency

if(!isset($_SESSION[‚users_id‘])) { // if session is no more active

if(isset($_COOKIE[‚users_id‘]) && isset($_COOKIE[‚username‘])) { // but cookie is set then renew session variables along them

$_SESSION[‚users_id‘] = $_COOKIE[‚users_id‘];

$_SESSION[‚username‘] = $_COOKIE[‚username‘];

}

// two variables for message and styling of the mesage with bootstrap

$msg = “;

$msgClass = “;

// default values of auxiliary variables

<!– ******************************************* –>

<!– script for appropriate scode removal –>

<!– ******************************************* –>

<!– obtain GET data from admin.php and trough –>

<!– POST submit remove data from database –>

<!– ******************************************* –>

<!DOCTYPE html>

<html>

<head>

<title> Bazaar score – remove script </title>

</head>

<body>

<a class=“navbar-brand“ href=“managecategory.php“>Bazaar category manager – part for Bazaar category management</a>

<a class=“navbar-brand“ href=“index.php“> –> return to main shop page</a>

</div>

</nav>

<?php if($msg != “): ?> <!– alert showing part –>

<?php endif; ?>

<h4>Confirmation of deletion selected category removal.</h4>

<br>

<br>

<?php // code for GET info about what to remove and submit removing approval

if(isset($_GET[‚subcategory_id‚]) && isset($_GET[‚category‚]) ){

// take a data from GET link generated by adminscript

$subcategory_id = htmlspecialchars($_GET[‚subcategory_id‘]);

$category = htmlspecialchars($_GET[‚category‘]);

$subcategory = htmlspecialchars($_GET[‚subcategory‘]);

} else if (isset($_POST[‚subcategory_id‘]) && isset($_POST[‚category‘]) && isset($_POST[‚subcategory‘])) { //grab score from POST – different behavior for removal

$subcategory_id = htmlspecialchars($_POST[‚subcategory_id‘]);

$category = htmlspecialchars($_POST[‚category‘]);

$subcategory = htmlspecialchars($_POST[‚subcategory‘]);

} else { //error info message

echo ‚<p class=“alert alert-danger“> Please specify any category for removal. </p>‘;

};

if(isset($_POST[‚submit‚])){

if($_POST[‚confirm‚] == ‚Yes‚ ){ // delete appropriate score post with imagescreenshot

//delete the screenshotimage from the

$subcategory_id = htmlspecialchars($_POST[‚subcategory_id‘]);

$category = htmlspecialchars($_POST[‚category ‚]);

$subcategory = htmlspecialchars($_POST[‚subcategory‘]);

// conect to the database

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PW, DB_NAME);

//Delete score data from the database

$sql = „DELETE FROM bazaar_category WHERE subcategory_id = $subcategory_id LIMIT 1″;

// execute SQL

mysqli_query($dbc, $sql);

// close database connection

mysqli_close($dbc);

// confirm executed command

echo ‚<p> The category <strong>‘ . $category . ‚</strong> with id <strong>‘ . $subcategory_id . ‚</strong> was succesfully removed. </p>‘;

} else {

echo ‚<p class=“alert alert-danger“ > The selected category was not removed. </p>‘;

}

} else if (isset($subcategory_id) && isset($category) ) {

echo ‚<h5>Are you sure to delete the next category item from bazaar? </h5>‘;

// show short describtion of score for deletion

echo ‚<p> <strong> subcategory_id: </strong> ‚ . $subcategory_id . ‚<br> <strong> Category: </strong>‘ . $category .

‚<br> <strong> Subcategory: </strong>‘ . $subcategory .

‚</p>‘;

//generating removing confirmation form

echo ‚<form method=“POST“ action=“removecategory.php“>‚; //not self but direct this script removecategory.php – we dont want include any GET data tahat previously send

echo ‚<input type=“radio“ name=“confirm“ value=“Yes“ /> Yes ‚;

echo ‚<input type=“radio“ name=“confirm“ value=“No“ checked=“checked“ /> No <br><br>‘;

echo ‚<input type=“hidden“ name=“subcategory_id“ value=“‚.$subcategory_id.'“ />‘;

echo ‚<input type=“hidden“ name=“category“ value=“‚.$category.'“ />‘;

echo ‚<input type=“hidden“ name=“subcategory“ value=“‚.$subcategory.'“ />‘;

echo ‚<input type=“submit“ class=“btn btn-danger“ value=“submit“ name=“submit“ />‚;

echo ‚</form>‚;

};

echo ‚<br><br>‘;

echo ‚<p> <a href = „managecategory.php“> <&lt Back to category management page. </a></p>‘;

</div>

<a class=“navbar-brand“ href=“https://cdesigner.eu“> Visit us on CDesigner.eu </a>

</div>

</body>

</html>

Conclusion and other thoughts

Our code snipets create baseline for required functionality for category management. From final code was omited parts related to user login and loged users persisency. Full bazaar app code can be obtaned from github here.

Bazaar – php example code – part 2 – structure of database tables

Article focus on database sctructure design for Bazaar app. Proces of normalization and atomisation of user data is important for minimalisation of redundant data in database tables.

Normalisation of the database tables

For our first aproach to establisching database structure also known as describing database schema we need explain some terms.

Schema – or database schema is description of data (tables and columns) in database, along with related objects and connections among them (relations).

For interconnection of separate table are used relations created with pair primary keys and foreign keys.

For further readings about database relationship, please visit page.

Normalization – means designing database with reduction of duplicate data as posssible with separation data into tables with relations between them.

These are the steps leading to normalised database structure:

Question yourself: What is the main thing you want your table to be about?
List all information you need to know about one thing in approriate table.
Break down all information about that thing into pieces for further organizing the table.

Basic concept focus on term of the atomic data. Atomic data are data that has been broken down into the smallest form needed for a database.

For further readin about data normalization please visit wikipedia page here.

Schema of bazaar table

Our design is break down into a four table, bazaar_user, bazaar_itme and bazaar_category. Relations between them is shown on text picture.

Bazaar app database schema drawing created in Dia editor

For simplifieng database creation process we prepared our first createdatabase.php script as follows:

<!– *************************************************************** –>

<!– PHP code for automation of preparation databasetable for bazaar app –>

<!-**************************************************************** –>

<!– Vrsion: 1.0 Date: 10.10.2020 by CDesigner.eu –>

<!-**************************************************************** –>

<?php // script for accessing database and first table structure establishement

require_once(‚appvars.php‘); // including variables for database

/* Attempt MySQL server connection. Assuming you are running MySQL

server with (user ‚admin‘ with password test*555) */

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PW, DB_NAME);

// Check connection

if($dbc === false){

die(„ERROR: Could not connect to database. “ . mysqli_connect_error());

}

// Attempt create table query execution

$sql1 = „CREATE TABLE bazaar_user (

users_id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,

username VARCHAR(40) NOT NULL,

pass_word VARCHAR(44) NOT NULL,

nickname VARCHAR(40) NOT NULL UNIQUE, /* not two identical nicknames allowed*/

first_name VARCHAR(40) NOT NULL,

lastname_name VARCHAR(40) NOT NULL,

addresss VARCHAR(40) NOT NULL,

city VARCHAR(40) NOT NULL,

ZIPcode VARCHAR(40) NOT NULL,

write_date DATETIME NOT NULL,

email VARCHAR(70) NOT NULL , /* not UNIQUE e-mails because one user can submitt different benchmark results */

/* message_text TEXT */ /* optionally add boolean fields for subscription */

GDPR_accept BOOLEAN NOT NULL default 0, /* BOOLEAN value if user accepted GDPR */

rules_accept BOOLEAN NOT NULL default 0, /* BOOLEAN value if user accepted portal rules */

avatar VARCHAR(70), /* link to image */

profile_text TEXT /* submit text from publisher */

)“;

$sql2 = „CREATE TABLE bazaar_item (

item_id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,

name_of_item VARCHAR(40) NOT NULL,

price_eur VARCHAR(40) NOT NULL,

subcategory_id INT NOT NULL,

users_id INT NOT NULL,

item_add_date DATETIME NOT NULL,

published BOOLEAN NOT NULL default 0,

screenshot1 VARCHAR(70), /* link to image of item 1 */

screenshot2 VARCHAR(70), /* link to image of item 2 */

screenshot3 VARCHAR(70), /* link to image of item 3 */

item_description TEXT, /* item description */

CONSTRAINT FK_subcategorz_id FOREIGN KEY (subcategory_id) REFERENCES bazaar_category(subcategory_id), /* foreign key N site of 1 to N relation */

CONSTRAINT FK_users_id FOREIGN KEY (users_id) REFERENCES bazaar_user(users_id) /* foreign key N site of 1 to N relation */

)“;

$sql3 = „CREATE TABLE bazaar_category (

subcategory_id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,

category VARCHAR(40) NOT NULL,

subcategory VARCHAR(40) NOT NULL

)“;

echo „<h2>Processing database tables for bazaar app.</h2>“;

echo ‚ | ************************************************************ | ‚;

echo „<br>“;

echo ‚ | PHP code for automation of preparation databasetable for bazaar app | ‚;

echo „<br>“;

echo ‚ | ****************************************************************** | ‚;

echo „<br>“;

echo ‚ | Vrsion: 1.0 Date: 10.10.2020 by CDesigner.eu | ‚;

echo „<br>“;

echo ‚ | ******************************************************************* | ‚;

echo „<br>“;

if(mysqli_query($dbc, $sql1)){

echo „Table 1 – bazaar_user created successfully.“;

echo „<br><br>“;

} else{

echo „ERROR: Could not able to execute $sql. “ . mysqli_error($dbc);

echo „<br><br>“;

};

if(mysqli_query($dbc, $sql3)){

echo „Table 3 – bazaar_item created successfully.“;

echo „<br><br>“;

} else{

echo „ERROR: Could not able to execute $sql. “ . mysqli_error($dbc);

echo „<br><br>“;

};

if(mysqli_query($dbc, $sql2)){

echo „Table 2 – bazaar_category created successfully – as last table because foreign key references.“;

echo „<br><br>“;

} else{

echo „ERROR: Could not able to execute $sql. “ . mysqli_error($dbc);

echo „<br><br>“;

}

// Close connection

mysqli_close($dbc);

After succesfull run of this script, we obtained these output in phpmyadmin page:

Obtained database tables with appropriate fileds structures

Conclusion and final thoughts

Established database structure prepared our startingpoint for obtaining data from users. database was created with emphasis on normaisation and atomisation of stred data.

Full sourcecode of our project for further study and free adaptation can be obtained from github here.

Bazaar – php example code – part 1 – first thoughts about application

Bazaar app enable management of sell offers from variety of registered clients. Main project focus on database design and implementation, login implemantation with SESSIONS extended with support of COOKIES, maintaining access to scripts along user roles. Our first part of series will explain basic interaction among pages and show page design expectation.

Enumeration of app expectation

Our Bazaar app will enable manage listenings for sell of used things. Functionality must be limited for registered users and some of management capability can be available only for admin user.

During process of preparation we expanded our first thoughts and adding new fatures as item cart or user roles.

Requirements for our app:

unregistered user must be able view all sell listenings on index.php page
list of items for sell must display last 5 products and user must be able select interesting category from drop-down menu
for all items must be available closer look page with further display and link to buy
only registered users can add itmes to a cart – for cart management we use column cart_number. If cart number is 0, item is available for buy. If this number is changed to users_id then item is not displayed anymore and is added into a cart of user (there is some dificulty, how to after some time release listening and reset number to 0 after some expiration period)
application will demonstrate mechanism for sinup user with login functionality
for user login persistency combination of SESSION with COOKIES mechanism will be used
on admin page and editprofile page is shown different content for loged in or unloged user
user can signin into a common user role with signup form
only admin has granted full access to admin page
registered user can add item to sell listening, but item is displayed only after admin approval of content
admin can manage categories available on bazaar portal

Block diagram of main page scripts

Next picture show names of main page scripts and flow during user work. Some pages/ scripts will be added next in development process for support of new important functionality. This solution depicts traditional, procedural approach for developmnet of PHP aplications.

Code scripts can be separated into a three main category: 1 – database creatonal scripts with further database altering scripts, 2 – cascade styles scrypts and 3 – main page scripts.

Description some of them:

createdatabase.php – main script for creating three database table for category, item and user data persistency.

alter.php and altercart.php – minor updates and addins into a existing database table. Up to a time of preapartion of this article user_role to bazaar_user table was added and cart_number in bazaar_item was added for support of user cart functionality.

index,php – main page with signup, login and logout functionality. Display will differ for unloged and loged in user. man contentent of the page are two table outputs os listened items for sell. persistent display show 5 latest listenings. Uper part enable select form dropdown menu category of interest for appropriate user and next show all listed items. Further improvement will be pagination of results.

login.php, logout.php and signup.php – all these scripts suport access management into a content of the page. Unregistered user must sign up with unique e-mail and name. Some of important data can be added itno a database next with editprofile.php script.

item.php and buyitem.php – all items listened on main index page have link leading into a item.php page. from GET data is obtained item_id that select form database all information provided to listed item. On item.php page is ling into a buyitem.php page. This page is avalable only for registred user and enable change cart_number data from 0 to users_id of appropriate user. This way we mark listed item as added into a user cart for further buy fullfilment (this option must be discused next, at time of writting tis article is not in a final stage).

cart.php – (on progress) – show all items marked with apropriate users_id of the loged user and show total price for all listened items. This page is a way for fullfil buy process and send info to site admin/ seller to arrange all important things for correct buy/sell process. (This part need further improvement of functionality, because to sell listening user must be marked in bazaar_item table with their users_id).

sellitem.php – enable add ifnfo about selled product.

editprofile.php – any further information about registered user is contained in this part of page.

admin.php with removeitem.php and managecategory.php and removecategory.php – access to this pages is enabled only for admin role of the user. This part enable change state of published boolean filed from 0 to 1 for display item to sell. All page categories can be managed through these gages.

appvars.php – central page with all important constants included on top part of pages in any other scripts.

Showcase of frontend and backend for bazaar app

This part show visual look of appropriate pages in state of time whne this article will be written. Further improvements will be added in next weeks during development and testing process.

Next photogallery shows additional page designs and dialog outputs for further reference what to expect from the project.

Main index page of Bazaar app

Conclusion and source code

In our first article focused on bazaar app page we make basic fundation about main page script and their interactions. During proces of description arrisen some new questions about ways how to extend functionality to fullfil requirements for working portal enabling selling and buying used goods from common users.

Ful code of the projects in as is state can be obtained from github here.

Benchmarkchart – php example code – part 5 – benchmark chart page and further thoughts

Article is focused on way how to alter existing code for showing submited post as a table. But scores are ordered in descending way and first 3 higest scores are differently styled. Latest part of article list number of ways hot to improve our aplication.

Numbering posted results in a chart

Before our update to code, we displayed in first table row ID number. For proper ordering from top score to bottom we must order query in descent way by score ID. Then we create auxiliary variable $postiton.

$position = 1; // first initialization of position

while($row = mysqli_fetch_array($output)){

… output omited

//echo „<td>“ . $row[‚id‘] . „</td>“; this line is changed to incrementing number showing position of the score in chart

echo „<td id=\“$display\“>“ . $position++ . „</td>“; // increases number of position after disply by one

$position variable is increased by 1 after all pass trough while loop.

Different colors for first positions

A bit harder update must be done for marking of first three score position for further stylling into a diferent colors.

Our goal for display first scores in a chart

In our code we introduced new variable $display. Into $display variable is assigned name for <td> id first, secondandthree and others. In switch statement along value of $position variable these values are added into a $display variable.

Next part show how this update is implemented in final php code:

$position = 1; // first initialization of position

while($row = mysqli_fetch_array($output)){ //next rows outputed in while loop

//echo “ <div class=\“mailinglist\“> “ ; class identification must differ first, two second and other position

switch ($position) { // along position from first to bottom displayed rows are marked with different names and recolored in style.css

case 1: $display=’first‘ ; break;

case 2:

case 3: $display=’secondandthree‘ ; break;

default: $display=’others‘ ;

};

echo „<tr>“;

//echo „<td>“ . $row[‚id‘] . „</td>“; this line is changed to incrementing number showing position of the score in chart

echo „<td id=\“$display\“>“ . $position++ . „</td>“; // increases number of position after disply by one

echo „<td id=\“$display\“>“ . $row[‚score‘] . „</td>“;

echo „<td id=\“$display\“>“ . $row[‚nickname‘] . „</td>“;

echo „<td id=\“$display\“>“ . $row[‚write_date‘] . „</td>“;

$image_location = IMAGE_PATH.$row[‚screenshot‘];

echo „<td id=\“gray_under_picture\“> <img src=\“$image_location\“ alt=\“ score image \“ height=\“95\“> </td>“;

echo „</tr>“;

echo “ </div> “ ;

}

echo „</table>“;

CSS style.css file was altered this way:

/* ************************************************ */

/* Benchamrkchart first position list display */

/* ************************************************ */

#first {

background-color: rgb(255, 129, 129);

text-align: center;

font-size:18px;

}

#secondandthree {

background-color: rgb(178, 255, 159);

text-align: center;

font-size:18px;

}

#others {

background-color: rgb(218, 255, 162);

text-align: center;

}

#gray_under_picture {

background-color: rgb(88, 88, 88);

text-align: center;

}

#chart_table_header {

text-align: center;

}

Full code of application can be obtained from github here.

Further improvements

As further improvement for benchmarkchart app we encorage you:

add submit page for admin of the page requests (for score removal)
add login mechanism
further visual adjustment of frontend

Benchmarkchart – php example code – part 4 – limiting access to admin page

Article describe way how to limit access into a admin page using header authentification. Before sending page data, user must by verified by providing username and password. Separate script authorize.php and adding third part into a appvars.php containing username and sha1 has for veriefied password added.

Using headers for authentication

Http headers authentifications provide simple way for limiting access for some resources on web. For further reading please wisit https://en.wikipedia.org/wiki/Basic_access_authentication.

For access to restricted resources user must provide correct username and pasword. If user enters these correctly, the browser goes ahed and sen page. This dialog between browser and server take place with headers, which are text messages with specific instruction on what is being requested or delivered.

Further reading about heder messages can be obtained from here, 4.10.2020.

Our authentification script looks like this

<!– ****************************************************************** –>

<!– PHP simple header authorization code –>

<!– ****************************************************************** –>

<!– Vrsion: 1.0 Date: 3-4.10.2020 by CDesigner.eu –>

<!– ****************************************************************** –>

<?php // leading part of page for simple header securing and basic variable setup

require_once(‚appvars.php‘); // including variables for database

$username = USERNAME;

$password_sha = PASSWORD_SHA1;

if (!isset($_SERVER[‚PHP_AUTH_USER‘]) ||
!isset($_SERVER[‚PHP_AUTH_PW‘]) ||

($_SERVER[‚PHP_AUTH_USER‘] != $username )
|| ( sha1($_SERVER[‚PHP_AUTH_PW‘]) != $password_sha) ) {

header(‚HTTP/1.1 401 Unauthorized‘);

header(‚WWW-Authenticate: Basic realm=“benchmark_admin“‚);

exit(‚<h2>Becnchmarkchart</h2>
Access denied, you must enter a valid username and password to access this page!

<p> <a href = „index.php„> <&lt Back to benchmarkresults homepage page. </a></p>‚);

}

For setting original username and password for reference and validation. Our appvar.php definition script was extended of third part as is shown next.

<!– **************************************************************** –><!– Part III | authorization constants –> <!-***************************************************************** –>
<?php

define(‚USERNAME‚, ‚administrator‚);

define(‚PASSWORD_SHA1‚, ‚02cc4d03794b3624b076e48a6d6d18b1f2af8dc1‚); // SHA value for wery weak demonstration password PassworD never use
in production environment!!!
// sha1 has code was generated for example by online app
http://www.sha1-online.com

Adding authorize.php script on secured pages

Our authorize.php script must be added to begining of all restricted pages. Script must be executed as first code before any HTML content ransfer because enables or disables ability to access appropriate web resources.

Next segment of code contains example of including code with require_once(); php function.

<!– ****************************************************************** –>

<!– PHP „self“ code handling administration of removal –>

<!– ****************************************************************** –>

<!– Vrsion: 1.0 Date: 27-XX.X.2020 by CDesigner.eu –>

<!– ****************************************************************** –>

<?php // leading part of page for simple header securing and basic variable setup

require_once(‚appvars.php‘); // including variables for database

require_once(‚authorize.php‚); // authorization script for simple header authorization

// two variables for message and styling of the mesage with bootstrap

$msg = “;

$msgClass = “;

// default values of auxiliary variables

For proper work of admin script is crucial to enable access to code on both admin.php and remove.php in same time. This requirement is fulfiled simply adding same code with same
header(‚WWW-Authenticate: Basic realm=“benchmark_admin„‚); .

After altering of our pages desribed way, our browser will promt for entering username and password as is shown on next picture.

Authentification request for enabling access to limited resources with HTML headers

Full code for further study

Most current version of aplication code can be obtained from github here.