Unable to properly handle the data sent by AJAX request

Question

I have a custom form on Wordpress (please don't suggest Contact Form 7) that allows users to donate to a charity. It validates the data using the jQuery Validate plugin. Once the data is deemed valid, it pushes the data to a 3rd party payment processor. This works great but I'd like to store the data on the form into the Wordpress DB (contact info and donation value).

I wasn't sure how to do so best & while PHP in the header of the template file would be easiest, since the submit action causes a redirect, I figured using AJAX was the best option. I followed this tutorial and now send JSON data to the AJAX "handler" file. My jQuery code (after validations etc) is below:

console.log("Donation Type: " + donationType + " Once-off");
string = JSON.stringify(submission);
console.log(string);

jQuery.ajax({
    url : "http://192.168.8.50/subsite/wp-admin/admin-ajax.php",
    type : 'post',
    data : {
        action : 'store_donation_to_db',
        post_id : post_id,
        fields : string
    },
    success : function( response ) {
        console.log( response );
    }
});

//ProcessDonation(submission);

Interpreting the AJAX data is the issue I'm facing. I've used the following:

add_action( 'wp_ajax_nopriv_store_donation_to_db', 'store_donation_to_db' );
add_action( 'wp_ajax_store_donation_to_db', 'store_donation_to_db' );

function store_donation_to_db() {
    //register log file path
    $path = plugin_dir_path( __FILE__). 'test-button-log.txt';
    //$handle = fopen($path,"w");


    // The message written to the file
    $new_line = "****************************************************************************\r\n";
    $log_entry = $_REQUEST;
    // Write the contents to the file, 
    // using the FILE_APPEND flag to append the content to the end of the file
    // and the LOCK_EX flag to prevent anyone else writing to the file at the same time
    //
    file_put_contents($path, $log_entry, FILE_APPEND | LOCK_EX);

    $variables = json_decode($_REQUEST['store_donation_to_db']);
    //file_put_contents($path, $variables, FILE_APPEND | LOCK_EX);
    $counter= 0;
    if ( defined( 'DOING_AJAX' ) && DOING_AJAX ) { 
        $string = "Hello";
        foreach($variables as $field)
        {
            $string .= $field." ".$counter;
            $counter++;
        }
        echo $string;
        die();
    }
    else {
        wp_redirect( get_permalink( $_REQUEST['post_id'] ) );
        exit();
    }
}

I got frustrated that the AJAX call would only return "Hello" so I added the line to write the $_REQUEST data into a text file, that data is below and looks like a JSON array:

store_donation_to_db{\"Title\":\"Mrs\",\"FirstName\":\"Daniel\",\"Surname\":\"Holland\",\"EmailAddress\":\"daniel@dfdsfdsf.com\",\"ContactNumber\":\"\",\"DateofBirth\":\"2017-07-10\",\"undefined\":\"0\",\"recurringCHK\":\"1\",\"DonationAmount\":\"1000\"}

Why am I unable to access the $variables array? Shouldn't the $_REQUEST variable be an array containing both post_id and fields as indexes with their corresponding values? I feel like I'm on the verge of getting this right and there's probably a stupid line I've got wrong (given how accurate the text file log is).

Answer 1

You are using AJAX with POST method, you can access the POST data using POST global variable in php.

$_POST['post_id] and $_POST['fields'] and then decode the json string and store it in DB.

Did you try this ?