mattermost/server/platform/services/sharedchannel

Shared Channel Service

Package sharedchannel implements Mattermost's shared channels functionality, for sharing channel content across Mattermost instances/clusters. Here are the key responsibilities:

Channel Sharing:

• Allows channels to be shared between different Mattermost instances/clusters
• Handles inviting remote clusters to shared channels
• Manages permissions and read-only status for shared channels

Content Synchronization:

• Syncs posts, reactions, user profiles, and file attachments between instances
• Handles permalink processing between instances
• Manages user profile images sync
• Maintains sync state and cursors to track what has been synchronized

Remote Communication:

• Processes incoming sync messages from remote clusters
• Sends updates to remote clusters when local changes occur
• Handles connection state changes with remote clusters
• Manages retry logic for failed sync attempts

Security:

• Validates permissions for shared channel operations
• Ensures users can only sync content they have access to
• Verifies remote cluster authenticity
• Sanitizes user data during sync

The service acts as a bridge between Mattermost instances, allowing users from different instances to collaborate in shared channels while keeping content synchronized across all participating instances.

This is implemented through a Service struct that handles all the shared channel operations and maintains the synchronization state. It works in conjunction with the RemoteCluster service to handle the actual communication between instances.