How to fetch Gmail messages using PHP and Gmail API

Other Questions Gmail
1

I’ve set up the Gmail API with the Google PHP client library and got it working. My initialization code looks like this:

set_include_path("./google-php-client/src/" . PATH_SEPARATOR . get_include_path());

require_once 'Google/Client.php';
require_once 'Google/Service/Gmail.php';

$googleClient = new Google_Client();
$googleClient->setClientId($config['gmail_client_id']);
$googleClient->setClientSecret($config['gmail_client_secret']);
$googleClient->setRedirectUri('http://localhost/callback');
$googleClient->addScope('email');
$googleClient->addScope('https://mail.google.com');
$googleClient->setAccessType('offline');

$mailService = new Google_Service_Gmail($googleClient);

Now I’m stuck on the next steps. What methods should I call to actually retrieve and read the email messages from a Gmail account? I need to get the message list and then fetch the content of individual emails. Any help with the proper API calls would be great.

2

After you have set up the initial connection, you should begin with the listMessages() function to retrieve the message IDs from your account. Once you have these IDs, you can proceed to use getMessage() to access the specific email content. This is a simple example:

// Fetch message list
$messagesList = $mailService->users_messages->listMessages('me');

// Iterate over the retrieved messages
foreach ($messagesList->getMessages() as $message) {
    $fullMessage = $mailService->users_messages->getMessage('me', $message->getId());
    
    // Extract email headers
    $headers = $fullMessage->getPayload()->getHeaders();
    
    // Get the email body
    $body = $fullMessage->getPayload()->getBody()->getData();
    $decodedBody = base64url_decode($body);
}

Just a note – remember that the email bodies are base64 encoded, so decoding is necessary before you can read them. Additionally, if you’re dealing with a large number of emails, consider using appropriate query parameters in listMessages() to limit the results.

3

don’t forget, the Gmail API returns different MIME types depending on the email format. plain text emails let you grab the body directly, but HTML emails need separate parsing. most emails nowadays have multiple parts, so check the parts array in the payload. pro tip: use maxResults in listMessages to avoid rate limits - test with 10-20 messages first before processing hundreds.

4

You can’t fetch messages without authentication first. Handle OAuth by redirecting users to Google’s auth server, then grab the authorization code from the callback URL. Once you’re authenticated, use users_messages->listMessages('me') to get message IDs, then users_messages->getMessage('me', $messageId) for individual emails. Watch out for multipart messages - they need extra parsing. The payload structure gets nested, so you’ll probably need to recursively search through parts to find the actual text. Don’t forget to check if your access token’s still valid before making API calls. Set up token refresh logic with the refresh token so you don’t get auth errors.