How can I execute non-blocking 'send and wait' actions in a loop?

Below is one common approach: instead of having your loop wait on each Gmail send-and-wait call, offload the API request so that it executes asynchronously. In a WordPress/PHP environment one effective method is to use non‐blocking HTTP requests. For example, when using the WordPress HTTP API you can set the request to be non‐blocking by passing the parameter blocking as false. This lets your loop dispatch the Gmail operation and continue immediately.

Below is an example of how you might use wp_remote_post() to trigger your Gmail send operation asynchronously:

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Example: Asynchronous HTTP Request in WordPress

PHPCopied
// URL of your endpoint or another handler that triggers the Gmail send
$endpoint_url = 'https://example.com/gmail-send-handler';

// Loop through your posts
if ( have_posts() ) :
    while ( have_posts() ) : the_post();
        // Gather any data you need to send for this particular post
        $post_data = array(
            'post_id' => get_the_ID(),
            'post_title' => get_the_title(),
            // Add additional data as needed…
        );

        // Dispatch asynchronous request.
        // The 'blocking' => false parameter means we don't wait for a response.
        wp_remote_post( $endpoint_url, array(
            'method'   => 'POST',
            'body'     => $post_data,
            'blocking' => false, // Execute asynchronously
            'timeout'  => 0.01   // Short timeout to force non-blocking behavior
        ) );

        // Continue immediately with the next iteration.
    endwhile;
endif;

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Additional Considerations

• Gmail API SDK Calls:
  If you are using the Gmail API PHP client library directly, note that it typically makes synchronous HTTP calls. In that case, you might consider one of these options:

  • Offload the API calls to a separate script (for example, via an internal HTTP endpoint) as shown above.
  • Use a background job or task queue (for instance, using WP-Cron or a dedicated background processing library) to handle the Gmail operations asynchronously.

• Error Handling and Feedback:
  Since the requests are asynchronous, you won’t immediately get feedback if one fails. Ensure you have logging or a callback mechanism in your asynchronous process to handle any errors or approval issues from Gmail.

• Security and Throttling:
  Be mindful of rate limits both on the Gmail API side and your WordPress server. Keeping your batch sizes or the number of asynchronous jobs in check is important to avoid getting rate-limited.

By dispatching each Gmail send call as a non-blocking HTTP request, your loop will continue immediately while each Gmail operation completes independently. This approach is widely used in WordPress plugin development where immediate user feedback is desired while background processing takes care of longer-running tasks.

Hope this helps,
Tycho