[WordPress] Ajax in WordPress: A Series on Protocols

00-ajax-protocol-syntax.php

<?php

/**
 * This function is purely for demonstration purposes of a blog post. There is lack of
 * sanitization, functions that are called that are not referenced, and areas that could
 * be refactored.
 * 
 * The point is to be relatively verbose for the sake of showing how multiple protocol
 * messages by be returned from a function, namely this one, that is called via Ajax
 * in WordPress.
 * 
 * The purpose of the function is to take the data in a CSV file and create users
 * based on the information in the file.
 */
public function process_file() {

	/* Greater sanitization is needed here, but to keep the example succint,
	 * I'm omitting it. Don't use this in production.
	 *
	 * Note that if no file number is specified in the request, then we return an
	 * an error code following our protocol.
	 */
	$file_number = -1;
	if ( isset( $_POST['file_number'] ) ) {
		$file_number = intval( $_POST['file_number'] );
	} else {
		
		echo 'no_file_number:-1';
		wp_die();
	}
	
	/* Greater sanitization is needed here, but to keep the example succint,
	 * I'm omitting it. Don't use this in production.
	 *
	 * Note that if no file number is specified in the request, then we return an
	 * an error code following our protocol.
	 */
	if ( isset( $_POST['csv_file'] ) ) {
		$csv_file = $_POST['csv_file'];
	} else {
	  
		echo "no_file_specified:-1"
		wp_die();
	}
	
	// Otherwise, at this point, we're good to go so we'll continue.
  
	/* Return the number of users. Assume they have been written to the database
	 * in the function call below. The function returns a collection of WP_User
	 * objects.
	 */
	$users = $this->create_wp_users_from_file( $csv_file );
  
	// Return a protocol-specific response.
	$total_users = count( $users );
	echo "completed:$total_users";
	wp_die();
}