Perché usare admin-ajax.php e come funziona?

1) Perché utilizzare admin-ajax.phpinvece di codificareiltuojsonin un file come themes/example/json.phpe codificai tuoi dati lì?

L'uso di admin-ajax.php significa che WordPress Core è caricatoe disponibile. Senza ciò,dovresti caricaremanualmentei file di cui haibisogno,che è unprocesso complicatoe soggetto aguasti senon conoscimolto,moltobene il Core. E quanto seibravo con la sicurezza Javascript?

2) Comefunziona admin-ajax.php? Non ci capiscomolto file. Caricatutte lefunzioniin modo chetu siaprontoper usarle?

1. Caricail WordPress Core,il che significa chepuoi usare cose come $wpdb e $WP_Query. Questo èfino alla riga 25.
2. Invia alcuneintestazioni - righe 37 - 41.
   
   1. Un'intestazione deltipo di contenuto
   2. Un'intestazioneperindicare aibrowser dinonmemorizzarenella cachei risultati
   3. Leintestazioniinteressanti sono quelleinviate da send_nosniff_headers()
   4. e nocache_headers() .
3. L'hook admin_init si attiva.
4. Le azioniprincipali sono definitee registrate dinamicamente - righe 46-73. Questinon verranno registrati ameno chenon sianonecessari,cioè ameno che vengono richiestitramite $_GET o $_POST.
5. Viene attivato l'hook API "heartbeat" - riga 75
6. Viene verificato lo stato di "accesso" dell'utente richiedentee ilfile viene attivato un hook amministrativo appropriato o "senzaprivilegi".

Glielementi # 1e # 6 sonoi motiviprincipaliper utilizzare l'API AJAX,amioparere. Haiil WordPress Core,di cui hai quasi certamentebisogno,e hai lo stesso sistema di sicurezza dell'accesso del resto di 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.phpfaparte dell ' API AJAX di WordPresse sì,gestisce le richieste sia dalbackend che dalfront. ecco cosa ho capitoper latua domanda che è:

2) Comefunziona admin-ajax.php?

per la logica puoi visita qui.

Questopresuppone chetu sappiagià come accodare JavaScript,ecc.

Pezzo 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);
        }
    });   

});
 

Pezzo 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) Perché usare admin-ajax.phpinvece di codificareiltuojsonin unfile file cometemi/esempio/json.phpe codificarei tuoi dati lì?

puòessere utile. admin- ajax.php vsmodello dipaginapersonalizzatoper richieste 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