Add blog_id to all notification messages (INTEGRA-49)

[budzanowski]

Summary

Implements INTEGRA-49 by adding blog_id to all notification messages sent to WPCOM endpoints. This enables the WPCOM notification proxy to properly work with the new client credentials authentication flow.

Problem

The current notification system sends messages to WPCOM without including the blog_id in the message body. While the blog_id is embedded in the URL endpoint, the WPCOM proxy system requires it in the message payload to properly route notifications in the client credentials authentication model.

Solution

1. Added blog_id property to NotificationsService class
2. Modified constructor to store the blog_id from Jetpack_Options::get_option('id')
3. Updated notify() method to include blog_id in all notification message bodies
4. Updated tests to expect blog_id in request verification

Changes Made

NotificationsService.php

• Added private $blog_id property to store WordPress.com blog ID
• Modified constructor to store blog_id instead of just using it in URL
• Updated notify() method to include blog_id in message body alongside item_id

NotificationsServiceTest.php

• Updated test expectation to include blog_id in request body verification
• Uses existing DUMMY_BLOG_ID constant for test consistency

Message Format Changes

Before:

'body' => array_merge($data, ['item_id' => $item_id])

After:

'body' => array_merge($data, [
    'item_id' => $item_id,
    'blog_id' => $this->blog_id,
])

Affected Notification Types

This change affects all notification types automatically:

• Product notifications (create/update/delete)
• Coupon notifications (create/update/delete)
• Shipping notifications (update)
• Settings notifications (update)

WPCOM Compatibility

The WPCOM counterpart already handles additional data in the request body:

private function get_data() {
    $body = json_decode($this->request->get_body() ?? '', true);
    $id   = $body['item_id'];
    unset($body['item_id']);
    return array_merge($body, ['id' => $id]);
}

This means the blog_id will be preserved and passed through to the notification processing logic.

Test Plan

• ✅ PHP coding standards pass
• ✅ Updated test expects blog_id in notification body
• ✅ All notification types automatically include blog_id
• Verify WPCOM proxy properly receives and processes blog_id
• Test notification flow with client credentials authentication

Impact

• Zero breaking changes - purely additive enhancement
• Backward compatible - WPCOM endpoints handle additional data gracefully
• Automatic coverage - all existing notification flows get blog_id inclusion
• Enables client credentials - satisfies WPCOM proxy requirements

Related Issues

• INTEGRA-49: Add blog_id to notification messages
• INTEGRA-30: Overall client credentials migration project
• Supports the broader effort to migrate from OAuth to client credentials authentication

🤖 Generated with Claude Code

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 66.2%. Comparing base (e5982a4) to head (2062bc5).
Report is 2 commits behind head on test/combined-branches.

Additional details and impacted files

@@                   Coverage Diff                    @@
##             test/combined-branches   #2989   +/-   ##
========================================================
  Coverage                      66.2%   66.2%           
  Complexity                     4837    4837           
========================================================
  Files                           826     826           
  Lines                         25808   25814    +6     
  Branches                       1269    1269           
========================================================
+ Hits                          17074   17080    +6     
  Misses                         8581    8581           
  Partials                        153     153           

Flag	Coverage Δ
js-unit-tests	66.4% <ø> (ø)
php-unit-tests	66.1% <100.0%> (+<0.1%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/API/WP/NotificationsService.php	97.9% <100.0%> (+0.1%)	⬆️

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