How to Use Facebook Messenger Platform API for Chatbots in PHP

Integrate Facebook Messenger Platform API

• Begin by installing necessary libraries. Use Composer to install the Facebook SDK for PHP:

 

composer require facebook/graph-sdk

• Ensure your server is running on HTTPS due to Facebook's security requirements for webhooks.

Set Up Webhooks Endpoint

• Create an endpoint that Facebook Messenger will communicate with. This endpoint will be set up to receive POST requests from Messenger when users send messages to your chatbot.

 

• Configure webhook verification using the verify token you set in your Facebook App Dashboard. The server should respond with the verify token if successfully challenged by Facebook:

$hub_verify_token = null;
if (isset($_REQUEST['hub_challenge'])) {
    $challenge = $_REQUEST['hub_challenge'];
    $hub_verify_token = $_REQUEST['hub_verify_token'];
}

if ($hub_verify_token === 'YOUR_VERIFY_TOKEN') {
    header('HTTP/1.1 200 OK');
    echo $challenge;
    exit;
}

• Implement logic to handle incoming messages and send responses. Use the SDK to parse and reply to messages:

if ($_SERVER['REQUEST_METHOD'] == 'POST') {
    $input = json_decode(file_get_contents('php://input'), true);

    $senderId = $input['entry'][0]['messaging'][0]['sender']['id'];
    $messageText = $input['entry'][0]['messaging'][0]['message']['text'];

    if ($messageText) {
        respondToMessage($senderId, "Received your message: " . $messageText);
    }
}

function respondToMessage($recipientId, $message) {
    $endpoint = 'https://graph.facebook.com/v2.6/me/messages?access_token=YOUR_PAGE_ACCESS_TOKEN';
    $responseData = [
        'recipient' => ['id' => $recipientId],
        'message' => ['text' => $message]
    ];

    $curl = curl_init($endpoint);
    curl_setopt($curl, CURLOPT_POST, true);
    curl_setopt($curl, CURLOPT_POSTFIELDS, json_encode($responseData));
    curl_setopt($curl, CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
    curl_exec($curl);
    curl_close($curl);
}

• Replace `YOUR_PAGE_ACCESS_TOKEN` and `YOUR_VERIFY_TOKEN` with your Facebook application's page access token and verify token, respectively.

Utilize Persistent Menu

• Enhance user interaction with the Persistent Menu feature. Set up pre-defined actions that users can perform at any time directly from Messenger's menu:

$menuData = [
    'persistent_menu' => [
        [
            'locale' => 'default',
            'composer_input_disabled' => false,
            'call_to_actions' => [
                [
                    'title' => 'My Account',
                    'type' => 'nested',
                    'call_to_actions' => [
                        [
                            'title' => 'Pay Bill',
                            'type' => 'postback',
                            'payload' => 'PAYBILL_PAYLOAD'
                        ]
                    ]
                ]
            ]
        ]
    ]
];

$menuEndpoint = 'https://graph.facebook.com/v2.6/me/messenger_profile?access_token=YOUR_PAGE_ACCESS_TOKEN';

$curl = curl_init($menuEndpoint);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, json_encode($menuData));
curl_setopt($curl, CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
curl_exec($curl);
curl_close($curl);

Handle User Events

• Detect and process different types of user interactions like quick replies, postbacks, and more by analyzing incoming webhook events:

function handleEvents($event) {
    if (isset($event['message']) && isset($event['message']['quick_reply'])) {
        $quickReplyPayload = $event['message']['quick_reply']['payload'];
        // Handle quick reply payload
    } elseif (isset($event['postback'])) {
        $postbackPayload = $event['postback']['payload'];
        // Handle postback payload
    }
}