#Mailchimp list subscribe "put" request

mc_put_req.php

<?php

/**
 * Utility function to subscribe a user to a MailChimp
 * list using the MC API 3.0
 *
 * @param array $args {
 *     Array of settings.
 *
 *     @type string $api_key Your MailChimp API key.
 *     @type string $list_id Your MailChimp List ID.
 *     @type string $email   The email you are subscribing to the list.
 *     @type string $status  The status you are setting the user as (subscribed|unsubscribed|cleaned|pending).
 *     @type array  $merge_fields {
 *          Merge field values.
 *
 *          @type string $FNAME MC default for user first name.
 *          @type string $LNAME MC default for user last name.
 *      }
 * }
 */
function sync_to_mailchimp( $args ) {
	$member_id = md5( strtolower( $args['email'] ) );
	$data_center = substr( $args['api_key'], strpos( $args['api_key'], '-' ) +1);
	$url = 'https://' . $data_center . '.api.mailchimp.com/3.0/lists/' . $args['list_id'] . '/members/' . $member_id;
	$json = json_encode([
		'email_address' => $args['email'],
		'status'        => $args['status'], // "subscribed","unsubscribed","cleaned","pending"
		'merge_fields'  => $args['merge_fields']
	]);
	$ch = curl_init( $url );
	curl_setopt( $ch, CURLOPT_USERPWD, 'user:' . $args['api_key'] );
	curl_setopt( $ch, CURLOPT_HTTPHEADER, ['Content-Type: application/json'] );
	curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
	curl_setopt( $ch, CURLOPT_TIMEOUT, 10 );
	curl_setopt( $ch, CURLOPT_CUSTOMREQUEST, 'PUT' );
	curl_setopt( $ch, CURLOPT_SSL_VERIFYPEER, false );
	curl_setopt( $ch, CURLOPT_POSTFIELDS, $json );
	$result = curl_exec( $ch );
	$http_code = curl_getinfo( $ch, CURLINFO_HTTP_CODE );
	curl_close( $ch );
	
	return $http_code;
}

mc_put_req_example.php

<?php
// Example of how to use the sync_to_mailchimp() function.
$args = array(
	'api_key'   => 'your api key',
	'list_id'   => 'your list id',
	'email'     => 'johndoe@example.com',
	'status'    => 'subscribed', // "subscribed","unsubscribed","cleaned","pending"
	'merge_fields' => array(
		'FNAME' => 'first_name',
		'LNAME' => 'last_name',
	)
);
$result = sync_to_mailchimp( $args );