Pourquoi utiliser admin-ajax.php et comment ça marche?

1) Pourquoi utiliser admin-ajax.php au lieu d'encoder votrejson dans un autre fichier comme themes/example/json.phpet yencoder vos données?

L'utilisation de admin-ajax.php signifie que WordPress Coreest chargéet disponible. Sans cela,vous auriezbesoin de chargermanuellement lesfichiers dont vous avezbesoin,ce quiest unprocessus compliquéet sujet à l'échec si vousne connaissezpastrèsbien le Core. Et,dans quellemesure êtes-vousbon avec la sécurité Javascript?

2) Commentfonctionne admin-ajax.php? Jen'y comprendspasgrand-chose fichier. Est-ce qu'il chargetoutes lesfonctionspour que vous soyezprêt à les utiliser?

1. Il charge WordPress Core,ce qui signifie que vouspouvez utiliser des élémentstels que $wpdb et $WP_Query. C'est àpeuprès à la ligne 25.
2. Ilenvoie quelquesen-têtes - lignes 37 à 41.
   
   1. Unen-tête detype de contenu
   2. Unen-têtepour dire auxnavigateurs dene pasmettreen cache les résultats
   3. Lesen-têtesintéressants sont ceuxenvoyéspar send_nosniff_headers()
   4. et nocache_headers() .
3. Le hook admin_init se déclenche.
4. Les actionsprincipales sont définieset enregistrées dynamiquement - lignes 46 à 73. Celles-cine serontenregistrées que sielles sontnécessaires,c'est-à-dire àmoins que ils sont demandés via $_GET ou $_POST.
5. Le hook API "heartbeat" se déclenche - ligne 75
6. Le statut "connecté" de l'utilisateur demandeurest vérifiéet le le hook administratif approprié ou "sansprivilège"est déclenché.

Les élémentsn ° 1et n ° 6 sont,àmon avis,lesprincipales raisons d'utiliser l'API AJAX. Vous avez WordPress Core,dont vous avezpresque certainementbesoin,et vous avez lemême système de sécurité de connexion que le reste de WordPress.

1) Why use admin-ajax.php instead of encoding your json in a separate file like themes/example/json.php and encode your data there?

Using admin-ajax.php means that the WordPress Core is loaded and available. WIthout that, you would need to hand load the files you need, which is a complicated process and prone to failure if you don't know the Core very, very well. And, how good are you with Javascript security?

2) How does admin-ajax.php work? I don't understand much from that file. Does it load all the functions so you are ready to use them?

1. It loads the WordPress Core, meaning you can use things like $wpdb and $WP_Query. That is through about line 25.
2. It sends a few headers-- lines 37 - 41.
   
   1. A content type header
   2. A header to tell browsers not to cache the results
   3. The interesting headers are those sent by send_nosniff_headers()
   4. and nocache_headers().
3. The admin_init hook fires.
4. Core actions are defined and registered dynamically-- lines 46 - 73. These won't be registered unless they are needed-- that is, unless they are requested via $_GET or $_POST.
5. The "heartbeat" API hook fires-- line 75
6. The "logged in" status of the requesting user is checked and the appropriate administrative or "no priviledge" hook is fired.

Items #1 and #6 are the primary reasons to use the AJAX API, in my opinion. You have the WordPress Core, which you almost certainly need, and you have the same login security system as with the rest of WordPress.

admin-ajax.phpfaitpartie de l ' API AJAX de WordPress,et oui,ilgère les demandes dubackendet dufront. voici ce quej'ai comprispour votre question quiest:

2) Commentfonctionne admin-ajax.php?

pour la logique ,vouspouvez visitezici.

Cela suppose que vous savez déjà commentmettreen file d'attente JavaScript,etc.

Pièce JavaScript:

 jQuery(document).ready(function($) {

    // We'll pass this variable to the PHP function example_ajax_request
    var fruit = 'Banana';

    // This does the ajax request
    $.ajax({
        url: ajaxurl,
        data: {
            'action':'example_ajax_request',
            'fruit' : fruit
        },
        success:function(data) {
            // This outputs the result of the ajax request
            console.log(data);
        },
        error: function(errorThrown){
            console.log(errorThrown);
        }
    });   

});
 

Pièce PHP:

 function example_ajax_request() {

    // The $_REQUEST contains all the data sent via ajax 
    if ( isset($_REQUEST) ) {

        $fruit = $_REQUEST['fruit'];

        // Let's take the data that was sent and do something with it
        if ( $fruit == 'Banana' ) {
            $fruit = 'Apple';
        }

        // Now we'll return it to the javascript function
        // Anything outputted will be returned in the response
        echo $fruit;

        // If you're debugging, it might be useful to see what was sent in the $_REQUEST
        // print_r($_REQUEST);

    }

    // Always die in functions echoing ajax content
   die();
}

add_action( 'wp_ajax_example_ajax_request', 'example_ajax_request' );

// If you wanted to also use the function for non-logged in users (in a theme for example)
 add_action( 'wp_ajax_nopriv_example_ajax_request', 'example_ajax_request' );
 

1) Pourquoi utiliser admin-ajax.php au lieu d'encoder votrejson dans un autre fichier commethemes/example/json.phpet yencoder vos données?

peut être utile. admin- ajax.php vsmodèle depagepersonnalisépour les requêtes Ajax

admin-ajax.php is part of the WordPress AJAX API, and yes, it does handle requests from both backend and front. here what i figure-out for your question that is:

2) How does admin-ajax.php work?

for the logic you can visit here.

This assumes you already know how to enqueue JavaScript, etc.

JavaScript Piece:

jQuery(document).ready(function($) {

    // We'll pass this variable to the PHP function example_ajax_request
    var fruit = 'Banana';

    // This does the ajax request
    $.ajax({
        url: ajaxurl,
        data: {
            'action':'example_ajax_request',
            'fruit' : fruit
        },
        success:function(data) {
            // This outputs the result of the ajax request
            console.log(data);
        },
        error: function(errorThrown){
            console.log(errorThrown);
        }
    });   

});

PHP Piece:

function example_ajax_request() {

    // The $_REQUEST contains all the data sent via ajax 
    if ( isset($_REQUEST) ) {

        $fruit = $_REQUEST['fruit'];

        // Let's take the data that was sent and do something with it
        if ( $fruit == 'Banana' ) {
            $fruit = 'Apple';
        }

        // Now we'll return it to the javascript function
        // Anything outputted will be returned in the response
        echo $fruit;

        // If you're debugging, it might be useful to see what was sent in the $_REQUEST
        // print_r($_REQUEST);

    }

    // Always die in functions echoing ajax content
   die();
}

add_action( 'wp_ajax_example_ajax_request', 'example_ajax_request' );

// If you wanted to also use the function for non-logged in users (in a theme for example)
 add_action( 'wp_ajax_nopriv_example_ajax_request', 'example_ajax_request' );

1) Why use admin-ajax.php instead of encoding your json in a separate file like themes/example/json.php and encode your data there?

may be this helpful.admin-ajax.php vs Custom Page Template for Ajax Requests