twilio-wp-plugin/TWILIO_SDK_MIGRATION.md

Twilio PHP SDK Migration Guide

This document outlines the migration of the Twilio WordPress Plugin from a custom API wrapper to the official Twilio PHP SDK v8.7.0.

Overview

The plugin now supports both the official Twilio PHP SDK and falls back to a custom implementation when the SDK is not available. This provides better error handling, type safety, and access to the latest Twilio features while maintaining backward compatibility.

Installation

Option 1: Using the Installation Script (Recommended)

1. Navigate to your plugin directory
2. Run the installation script:

   chmod +x install-twilio-sdk.sh
   ./install-twilio-sdk.sh
   

Option 2: Manual Installation with Composer

1. Ensure Composer is installed on your system
2. Run in the plugin directory:

   composer install
   

Option 3: Manual Download

1. Download Twilio SDK v8.7.0 from: https://github.com/twilio/twilio-php/releases
2. Extract to vendor/twilio/sdk/
3. Create autoloader file (see installation script for reference)

How It Works

Auto-Detection

The plugin automatically detects if the Twilio SDK is available by:

1. Checking for vendor/autoload.php
2. Verifying the Twilio\Rest\Client class exists
3. Attempting to initialize the client

Dual-Mode Operation

SDK Mode (When Available):

• Uses official Twilio PHP SDK classes
• Better error handling with specific Twilio exceptions
• Type safety and IDE support
• Automatic retries and rate limiting
• Official TwiML generation classes

Fallback Mode (Default):

• Uses custom WordPress HTTP API calls
• String-based TwiML generation
• Maintains all existing functionality
• No external dependencies required

Code Changes

API Class Updates

The TWP_Twilio_API class now:

• Detects SDK availability in the constructor
• Routes all methods through SDK when available
• Falls back to custom implementation seamlessly
• Maintains identical method signatures for compatibility

TwiML Generation

New Unified Approach:

// Works with both SDK and fallback
$api = new TWP_Twilio_API();
$response = $api->create_twiml();
$response->say('Hello world', ['voice' => 'alice']);
$response->dial('+1234567890', ['timeout' => 30]);
$twiml = $response->asXML();

Old Approach (Now Deprecated):

// String concatenation - now handled automatically
$twiml = '<?xml version="1.0" encoding="UTF-8"?>';
$twiml .= '<Response>';
$twiml .= '<Say voice="alice">Hello world</Say>';
$twiml .= '</Response>';

Updated Classes

1. TWP_Twilio_API: Core API wrapper with SDK integration
2. TWP_Webhooks: All webhook handlers updated to use new TwiML builder
3. TWP_Callback_Manager: Outbound calling and callback management
4. TWP_Workflow: Call flow TwiML generation
5. TWP_Agent_Manager: Agent call routing

Benefits

With SDK Available

• Better Error Handling: Specific exception types for different error scenarios
• Type Safety: IDE support and parameter validation
• Official Support: Direct access to latest Twilio features
• Reliability: Built-in retry logic and rate limiting
• Performance: Optimized for high-volume operations

Without SDK (Fallback)

• No Dependencies: Works on any PHP installation
• Lightweight: Minimal memory footprint
• Compatibility: Works with older PHP versions
• Reliability: Battle-tested custom implementation

Supported PHP Versions

• With SDK: PHP 8.0+ (SDK v8.7.0 supports PHP 8.4)
• Without SDK: PHP 7.2+ (fallback implementation)

Feature Support

API Operations

• ✅ Make calls
• ✅ Send SMS
• ✅ Get call details
• ✅ Update active calls
• ✅ Manage phone numbers
• ✅ Search available numbers
• ✅ Purchase/release numbers
• ✅ Configure webhooks

TwiML Generation

• ✅ Say (text-to-speech)
• ✅ Dial (with caller ID, timeout)
• ✅ Gather (digit collection with prompts)
• ✅ Enqueue (queue management)
• ✅ Record (voicemail recording)
• ✅ Redirect (call flow control)
• ✅ Hangup

Advanced Features

• ✅ Webhook signature validation
• ✅ Conference calling
• ✅ Queue management
• ✅ Agent group routing
• ✅ Callback requests
• ✅ Voicemail transcription

Testing

Verifying SDK Installation

Check the admin dashboard or logs for:

TWP Plugin: Twilio SDK v8.7.0 loaded successfully

API Testing

Use the plugin's test call feature to verify:

1. Outbound calling works
2. TwiML generation is valid
3. Webhooks receive proper responses
4. Error handling functions correctly

Manual Testing

1. Test Call Flow: Make a test call to verify TwiML generation
2. Webhook Testing: Use Twilio's webhook debugger
3. Error Scenarios: Test invalid numbers, network failures
4. Queue Operations: Test agent groups and callbacks

Troubleshooting

SDK Not Loading

Check autoloader exists:

ls -la vendor/autoload.php

Check SDK files:

ls -la vendor/twilio/sdk/

PHP Version:

php -v  # Should be 8.0+ for SDK support

Common Issues

1. "Class 'Twilio\Rest\Client' not found"

   • SDK not properly installed
   • Run installation script again

2. "Call to undefined method"

   • Fallback mode active
   • Check SDK installation
   • Verify PHP version compatibility

3. "Permission denied" on installation script

   • Run: chmod +x install-twilio-sdk.sh

Fallback Mode Indicators

The plugin uses fallback mode when:

• No vendor/autoload.php file
• Twilio classes not available
• SDK initialization fails
• PHP version incompatibility

Migration Timeline

• ✅ Phase 1: Core API wrapper updated
• ✅ Phase 2: Webhook classes migrated
• ✅ Phase 3: TwiML generation unified
• ✅ Phase 4: Error handling improved
• ⏳ Phase 5: Testing and validation
• 📋 Phase 6: Documentation complete

Rollback Plan

If issues arise, the plugin automatically falls back to the custom implementation. No manual intervention required.

To completely disable SDK usage:

1. Remove or rename vendor/ directory
2. Plugin will automatically use fallback mode

Support

For issues related to:

• Plugin functionality: Check WordPress error logs
• Twilio API errors: Check Twilio Console debugger
• SDK-specific issues: Refer to Twilio PHP SDK documentation

Resources

• Twilio PHP SDK GitHub
• Twilio API Documentation
• TwiML Reference
• WordPress HTTP API