Subscription System Flow

This flowchart illustrates the complete subscription workflow when a user clicks a genhub:// protocol link to subscribe to a publisher.

Overview

The subscription system enables users to discover and subscribe to content publishers through shareable genhub:// protocol links. Once subscribed, publishers appear in the Downloads UI sidebar, and their catalogs become browsable.

Flow Diagram

Key Components

Protocol Handler

• File: App.xaml.cs (protocol registration)
• Trigger: genhub://subscribe?url=<definition-url>
• Action: Activates subscription workflow

Subscription Confirmation Dialog

• ViewModel: SubscriptionConfirmationViewModel.cs
• Purpose: Display publisher information and request user confirmation
• Data Displayed:
  • Publisher name, description, avatar
  • Website and support URLs
  • List of available catalogs
  • Referral publishers (if any)

Subscription Storage

• File: subscriptions.json (user data directory)
• Service: PublisherSubscriptionStore.cs
• Schema:

{
  "subscriptions": [
    {
      "publisherId": "unique-id",
      "definitionUrl": "https://...",
      "subscribedDate": "2026-03-15T10:30:00Z",
      "lastUpdated": "2026-03-15T10:30:00Z"
    }
  ]
}

Catalog Fetching

• Service: PublisherDefinitionService.cs
• Process:
  1. Read catalog URLs from definition
  2. Fetch each catalog JSON
  3. Parse and validate schema
  4. Store in memory for UI display

Downloads UI Integration

• ViewModel: DownloadsBrowserViewModel.cs
• Sidebar: Displays subscribed publishers alongside core providers
• Content Browser: Shows catalog content when publisher selected

Error Handling

Network Errors

• Retry mechanism with user prompt
• Fallback to mirror URLs (if defined)
• Graceful degradation (show cached data)

Validation Errors

• Schema version checking
• Required field validation
• URL format validation

User Experience

• Non-blocking notifications
• Clear error messages
• Undo subscription option

Related Files

• GenHub.Core/Models/Providers/PublisherDefinition.cs
• GenHub.Core/Services/Publishers/PublisherDefinitionService.cs
• GenHub/Features/Content/ViewModels/Catalog/SubscriptionConfirmationViewModel.cs
• GenHub/Features/Downloads/ViewModels/DownloadsBrowserViewModel.cs
• GenHub.Core/Services/Publishers/PublisherSubscriptionStore.cs