Case Study: Zero-Downtime Deployments with DeployHQ and Pressidium

Customer Background

A leading web agency managing a high-traffic WordPress site on Pressidium faced a critical challenge: implementing automated deployments without compromising Pressidium's stringent security measures. They needed a solution that offered both automation and robust security.

Challenge

The customer faced specific limitations with Pressidium's hosting environment:

• SFTP access was available (Pressidium SFTP Documentation)
• SSH command execution was restricted for security reasons
• Cache purging was necessary after deployments

Solution

We implemented a Zero Downtime Deployment strategy using DeployHQ with a custom cache purging mechanism through HTTP Post hooks.

1. DeployHQ Configuration

# DeployHQ Settings
---
server:
  host: sftp.pressidium.com
  port: 22
  protocol: sftp
  path: /public_html/wp-content/themes/custom-theme

excluded_files:
  - .git
  - node_modules
  - .env

2. Cache Purging API Implementation

// wp-content/mu-plugins/cache-purge-api.php

<?php
add_action('rest_api_init', function () {
    register_rest_route('cache-api/v1', '/purge', array(
        'methods' => 'POST',
        'callback' => 'handle_cache_purge',
        'permission_callback' => 'verify_basic_auth'
    ));
});

function verify_basic_auth($request) {
    // Get the Authorization header
    $auth_header = $request->get_header('Authorization');

    if (!$auth_header || strpos($auth_header, 'Basic ') !== 0) {
        return false;
    }

    // Extract credentials
    $credentials = base64_decode(substr($auth_header, 6));
    list($username, $password) = explode(':', $credentials);

    // Compare with configured credentials
    return $username === defined('CACHE_API_USER') ? CACHE_API_USER : '' &&
           $password === defined('CACHE_API_PASS') ? CACHE_API_PASS : '';
}

function handle_cache_purge($request) {
    if (function_exists('pressidium_purge_cache')) {
        pressidium_purge_cache();
        return new WP_REST_Response(['status' => 'success'], 200);
    }

    return new WP_REST_Response(['status' => 'error'], 500);
}

3. Configuration in wp-config.php

// wp-config.php
define('CACHE_API_USER', 'your-username');
define('CACHE_API_PASS', 'your-secure-password');

4. DeployHQ Post-Deploy HTTP Hook

In DeployHQ's project settings:

1. Navigate to Integrations → HTTP Post
2. Add new hook with:

    URL: https://your-site.com/wp-json/cache-api/v1/purge
    Username: your-username
    Password: your-secure-password

5. Testing the Endpoint

You can test the endpoint using curl:

curl -X POST \
     -u "your-username:your-secure-password" \
     https://your-site.com/wp-json/cache-api/v1/purge

Results

The implementation achieved:

• Zero-downtime deployments via SFTP
• Secure cache purging through WordPress REST API
• Automated deployment workflow
• No need for SSH command execution

Benefits

1. Maintained security compliance with Pressidium
2. Automated deployment process
3. Minimal deployment downtime
4. Secure cache purging mechanism

Technical Details

Security Considerations

• REST API endpoint protected by basic authentication
• HTTPS encryption for all API calls
• Secure key storage in wp-config.php

Implementation Steps

1. Configure DeployHQ SFTP deployment
2. Install cache purging API code
3. Configure wp-config.php with basic auth
4. Set up DeployHQ post-deploy hook

Conclusion

This solution successfully worked around Pressidium's SSH restrictions while maintaining a robust deployment process with automated cache purging.

Related Documentation

• Pressidium SFTP Access
• DeployHQ HTTP Post Hooks
• WordPress REST API

This case study demonstrates how to implement automated deployments within hosting restrictions while maintaining security and performance.