PHP Dynamic Qr code - Generator of dynamic and static Qr code V1.0

Dashboard

The dashboard is the main page of the script. In this section there is a counter of the total number of qr code in the database, and in particular also the number of dynamic and static ones. There is also a counter regarding the number of scans of the dynamic qr code.
The script offers 2 examples of dynamic charts created with chart.js The first shows a weekly report of the number of qr codes created (dynamic and static), the second graph offers an overview of the number of scans of dynamic qr codes.

1. Report of qr code
Dashboard

                            
//The values are determined by counting the number of lines through the getValue library function:

$db->getValue ("table_name", "count(*)");


//A custom query is available for the value of the scans that sum all the values of the scan column:

$db->query("SELECT sum(scan) FROM dynamic_qrcodes");
                            
                        

2. Chart
Chart code - PHP

                            
//For the first chart I select the "created_at" column (of the dynamic and static qr code tables) with a value between the current date and 7 days less:

$db->query("select `created_at`, `scan` from "table_name" where `created_at` > curdate()-7;");


/*I also select the "scan" column with the same criteria because I will need it for the second graph.
I scan the entire array and through a switch having as expression the substring of type YYYY-MM-DD of the results extracted from the database.
N.B. In our database we store the "created_at" field also with the date and time because it is useful for sorting the qr code:                          */

foreach ($result as $row) {
    switch (substr($row['created_at'],0,10)){
    case 
    ...
    }
}    
                            
                        

Chart code - JS

                            
/*For the complete functioning of the chart.js library visit the link in the documentation.
The js codes of the graphs are found in the <footer> tag. We make a graph dynamic by modifying the "labels" attribute and the "data" attribute 
with values obtained from database.                                                                                                                     */

//In particular for "labels" we print 7 dates in the format YYYY-MM-DD.


<?php echo date("Y-m-d",mktime(0,0,0,date('m'),date('d'),date('Y'))); ?>
<?php echo date("Y-m-d",mktime(0,0,0,date('m'),date('d') - 1,date('Y'))); ?>
<?php echo date("Y-m-d",mktime(0,0,0,date('m'),date('d') - 2,date('Y'))); ?>
...


//Then for the "date" attribute we print the variables obtained from the previous calculations, for example:

<?php echo $dynamic_sixday ?>           
<?php echo $static_today ?>             
<?php echo $scan_twoday ?>
                            
                        

List All

The structure of the code for the listing process is the same for all types of QR code. Below there is an example for dynamic qr codes.
There is a main page, in this case dynamic_qrcodes.php, which contains the code to retrieve the data necessary for the table and an external page called search_order.php which implements functions for searching and sorting the qr code.
The HTML code includes: the flash_message.php file for managing the various messages to be printed, the filters.php file for managing the search and sorting filters and the dynamic_table.php file with the code that creates the entire table.

dynamic_qrcodes.php

                            
//We retrieve the database instance and define which columns to extract from the database for the table we need:

$db = getDbInstance();
$select = array('id', 'filename', 'identifier', 'link', 'qrcode', 'scan', 'created_at', 'updated_at');


/*We define the parameters with which it is possible to sort the qr codes in the table.
N.B. The parameters for ascending and descending sorting are always included separately in addition to those chosen by us.                              */

$search_fields = array('filename', 'identifier', 'link');
require_once BASE_PATH . '/includes/search_order.php';


/*We use the variable $page to keep track of the page where we are. 
By default the value is "1" and we need it because we can set an element limit for each page with a special library function:                           */

$page = filter_input(INPUT_GET, 'page', FILTER_SANITIZE_FULL_SPECIAL_CHARS) ?? 1;
$db->pageLimit = 15;


//We build the pagination with the elements extracted from the database through a convenient library function:

$rows = $db->arraybuilder()->paginate('dynamic_qrcodes', $page, $select);
$total_pages = $db->totalPages;
                            
                        

dynamic_table.php

                            
//We define the dimensions for each column. Example:
<thead>
    <tr>
        <th width="5%">ID</th>
        <th width="15%">Filename</th>
        <th width="18%">Unique redirect identifier</th>
        ...
    </tr>
</thead>


//We print the entire array of results extracted from the database in the respective columns. Example:

<tbody>
    <?php foreach ($rows as $row): ?>
    <tr>
        <td><?php echo $row['id']; ?></td>
        <td><?php echo htmlspecialchars($row['filename']); ?></td>
        <td><?php echo htmlspecialchars($row['identifier']); ?></td>
        ...
        <td>
/*The script includes 3 operations: modification, cancellation, download of the qr code. All 3 have their own button but the modification operation 
refers to an external link, the cancellation is managed through a "modal fade" within the same page, while the HTML "download" attribute 
is simply used for the download:                                                                                                                    */

<!-- EDIT -->
    <a href="edit_dynamic.php?filename=<?php echo $row['filename']; ?>&dynamic_id=<?php echo $row['id']; ?>&operation=edit" class="btn btn-primary"><i class="fas fa-edit"></i></a>
    
<!-- DELETE -->
    <a href="#" class="btn btn-danger delete_btn" data-toggle="modal" data-target="#confirm-delete-<?php echo $row['id']; ?>"><i class="fas fa-trash"></i></a>
                    
<!-- DOWNLOAD -->
    <a href="<?php echo PATH.htmlspecialchars($row['qrcode']); ?>" class="btn btn-primary" download><i class="fa fa-download"></i></a>
    
        </td>
    </tr>
/*For cancellation, the modal uses an external page (in this case delete_dynamic.php) using a form within the main page 
that includes two hidden input fields: filename, del_id. Before confirming the cancellation, a different message is shown depending on the type of QR code.
*/

//We conclude the end of printing the elements and the table body:

<?php endforeach; ?>
</tbody>
                            
                        

How does the insertion of a dynamic qr code work?

The main page dedicated to the insertion is add_dynamic.php the form HTML-tag is also declared on this page, however the input fields are separated in another page called add_dynamic_form.php for a matter of code reusability

add_dynamic.php

                            
//Let's create an instance of the class for the dynamic Qr code we discussed earlier:

require_once BASE_PATH . '/lib/Dynamic_Qrcode/Dynamic_Qrcode.php';
$dynamic_qrcode = new Dynamic_Qrcode();


//We verify that the form has been sent with the POST method and we call the add() function shown above:

if ($_SERVER['REQUEST_METHOD'] === 'POST')
    $dynamic_qrcode->add();

                            
                        

add_dynamic_form.php

                            
/*The input fields are recognized by the class through the "name" attribute. For example, the underlying input creates the "colorpicker" tool 
whose data will be sent and processed by the class with the name (attribute) "foreground" and the chosen value "value":                                 */

<input type="text" class="form-control" id="foreground" name="foreground" value="#000000">


//Similarly, there are some types of selection inputs with different options. The input is sent with a "name" and with a "value":

<select name="level" class="form-control">
    <option value="L">L - Smallest</option>
    <option value="M">M - Medium</option>
    <option value="Q">Q - High</option>
    <option value="H">H - Best</option>
</select>

                            
                        

How does the insertion of a static qr code work?

The main page dedicated to the insertion is add_static.php Unlike the previous creation page, the one for static qr codes does not provide a single form HTML-tag but each type of static qr code has its own form. For the input fields there is a secondary page called add_static_form.php which contains the menu of the various types of qr code that can be created and for each card (for each type) another file is included with the individual input fields, for example text.php

add_static.php

                            
//Let's create an instance of the class for the static Qr code we discussed earlier:

require_once BASE_PATH . '/lib/Static_Qrcode/Static_Qrcode.php';
$static_qrcode = new Static_Qrcode();


/*We verify that the form has been sent with the POST method and with a control switch we examine the type of qr code that you want to create 
through $ _GET ['type'] present in the link after sending the corresponding form. Each type corresponds to a different class method 
that sends as parameters the input data of the form with the POST method. Example with the type "text":                                                 */

if ($_SERVER['REQUEST_METHOD'] === 'POST'){
    switch($_GET['type']){
        case 'text':    $static_qrcode->textQrcode($_POST['text']); break;
        ...
    }
}

                            
                        

add_static_form.php

                            
/*Within this page there is a menu divided into tabs in which each contains a different form depending on the type of static qr code to create.
Example with "text" type:                                                                                                                               */

<ul class="nav nav-tabs" role="tablist">
    <li class="nav-item">
        <a class="nav-link active" data-toggle="pill" href="#text" role="tab" aria-controls="custom-tabs-four-home" aria-selected="true">Text 
            <i class="fas fa-align-left"></i>
        </a>
    </li>
    ...
</ul>

<div class="tab-content" >
    <div class="tab-pane fade show active" id="text" role="tabpanel" aria-labelledby="custom-tabs-four-home-tab">
        <?php include BASE_PATH . '/forms/static/text.php'; ?>      
    </div>
    ...
</div>
                
                        

text.php

                            
/*Each page relating to a type of qr code has the same structure. In particular, it is characterized by a form which once sent provides the input data 
to the main creation page with the type inside the link (?type=), the options to customize the qr code and the individual input fields different from 
type to type. Example for "text" type:                                                                                                                  */

<form class="form" action="./add_static.php?type=text" method="post" id="static_form" enctype="multipart/form-data">
    <?php include BASE_PATH.'/forms/qrcode_options.php'; ?>
<!-- Input forms -->
</form>
                
                        

How does the modification of a qr code work?

The modification process is essentially the same for both types of QR code.
For dynamic qr code is possible to change: the file name, the url and is possible to enable or disable the redirect when the qr code is scanned. It is not possible to change the image format of the QR code as well as its unique identifier.
For static qr codes is only possible to change the file name, since by definition a static qr code cannot be changed in its content. The image format of the qr code cannot be changed.
Below there is an example of the modification process for dynamic qr code, which I repeat is the same for both types.
The main page dedicated to the edit is edit_dynamic.php the form HTML-tag is also declared on this page, however the input fields are separated in another page called edit_dynamic_form.php for a matter of code reusability.

edit_dynamic.php

                            
//Let's create an instance of the class for the Dynamic Qr code we discussed earlier

require_once BASE_PATH . '/lib/Dynamic_Qrcode/Dynamic_Qrcode.php';
$dynamic_qrcode = new Dynamic_Qrcode();


/*We retrieve from the link the id of the qr code and the requested operation (edit). I chose to add this additional parameter 
because from the qr code table it is possible to add different operations for each one.                                                                 */

$dynamic_id = htmlspecialchars($_GET['dynamic_id'], ENT_QUOTES, 'UTF-8');
$operation = htmlspecialchars($_GET['operation'], ENT_QUOTES, 'UTF-8');


//We verify that the form has been sent with the POST method and we call the edit() function shown above:

if ($_SERVER['REQUEST_METHOD'] === 'POST') 
    $dynamic_qrcode->edit();
    
//If the requested operation is edit, we retrieve the information needed to fill in the edit form through the id of the qr code:

if ($edit){
    $db->where('id', $dynamic_id);
    $dynamic_qrcode = $db->getOne('dynamic_qrcodes');
}
                            
                        

edit_dynamic_form.php

                            
/*The input fields are similar throughout the script. What changes is the declaration of the "value" attribute. 
In fact, the value is retrieved from the database only if the edit operation has been chosen:                                                           */

<input type="text" name="identifier" value="<?php echo htmlspecialchars($edit ? $dynamic_qrcode['identifier'] : '', ENT_QUOTES, 'UTF-8'); ?>">
                
                        

How does the deletion of a qr code work?

The deletion process is essentially the same for both types of QR code. It is a very simple process, here is an example for static qr codes.
There is a single delete_dynamic.php delete page which is reached through a unique link for each element in the qr code table.

delete_dynamic.php

                            
//Let's create an instance of the class for the Static Qr code we discussed earlier:

require_once BASE_PATH . '/lib/Static_Qrcode/Static_Qrcode.php';
$static_qrcode = new Static_Qrcode();


/*We verify that the form has been sent with the POST method and we call the cancel() function shown above. 
To this function we send as parameters the id of the qr code and the name of the file                                                                   */

if ($_SERVER['REQUEST_METHOD'] === 'POST')
    $static_qrcode->cancel($_POST['del_id'], $_POST['filename']);
                            
                        

What happens when i scan a dynamic qr code?

The dynamic QR code reading process is quite simple. There is a single read.php page that does all the operations. By default this page is located outside the main directory, however with your modifications it is possible to change its location. Instead, it is easier to change the name of this page, taking care to change the name also in the classes where the qr code is generated

read.php

                            
//Each link is generated in the form /read.php?id=xxxxx, so we retrieve the present id:

$get_id = htmlspecialchars($_GET['id'], ENT_QUOTES, 'UTF-8');


//We retrieve the database instance and select the link associated with the unique id as well as its status (enabled or disabled):

$db = getDbInstance();
$state = $db->query("SELECT state FROM dynamic_qrcodes WHERE identifier='$get_id'");
$link = $db->query("SELECT link FROM dynamic_qrcodes WHERE identifier='$get_id'");


//We increase the scan field since the qr code has just been scanned:

$update = $db->query("UPDATE dynamic_qrcodes SET scan=scan+1 WHERE identifier='$get_id'");


/*If the qr code is enabled we proceed with a normal HTML redirect towards the associated link; otherwise we print a simple message
informing the user that the link is disabled:                                                                                                           */

if($state[0]['state'] == 'enable'){
        echo '<meta http-equiv="refresh" content="0; URL='.$link[0]['link'].'" />';         
        echo 'Loading...';                                                                  
}
else
    echo 'Disabled link';
    
    
//N.B. Any custom pages to show during the redirect are not included in this script.
                            
                        

EXTRA

My script is in constant development and I hope to expand it from time to time with more and more useful features, so stay tuned for the updates.
With the first version, in the classes that realize the 2 types of qr code, an additional method not mentioned in the above documentation called addLogo() is included. To add this functionality you need to delete the comment characters inside the class and add the input fields to the forms for the user to upload the logo. However, this feature is not recommended as it can cause different QR code scanning errors depending on the scanner applications.

Updates

• Version 1.0 – September, 2020 (Initial release)

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