Add OpenAPI Documentation Extension for HTTP Workflow Triggers

[cristinamudura]

📋 Summary

This PR introduces a new Elsa.Http.OpenApi extension module that automatically generates OpenAPI 3.0 documentation for HTTP endpoints exposed by Elsa workflows. The extension provides workflow-aware API documentation with interactive ReDoc interface.

✨ Key Features

• 🔍 Automatic Endpoint Discovery: Extracts HTTP trigger endpoints from workflow definitions with complete metadata
• 📊 OpenAPI 3.0 Specification: Generates standard-compliant OpenAPI JSON with workflow-specific organization
• 📖 Interactive Documentation: Provides ReDoc UI at /documentation for browsing and testing endpoints
• 🏷️ Workflow-Aware Organization: Groups endpoints by workflow name as tags and includes definition IDs in descriptions

🏗️ Architecture

Core Components

• IWorkflowEndpointExtractor: Service that extracts HTTP endpoints from workflows with metadata lookup
• IOpenApiGenerator: Service that generates OpenAPI 3.0 JSON specification
• IElsaVersionProvider: Dedicated service for Elsa Core version detection
• EndpointDefinition: Model representing HTTP endpoints with workflow metadata

Usage

builder.Services.AddElsa(elsa => elsa
    .UseHttp(http =>
    {
        http.ConfigureHttpOptions = options => configuration.GetSection("Http").Bind(options);
        
        if (useCaching)
            http.UseCache();
            
        // Add OpenAPI support for HTTP triggers
        http.UseOpenApi();
    })
);

// Elsa HTTP Endpoint activities.
app.UseWorkflows();

app.MapControllers();
...
// Map OpenApi Endpoints
app.MapWorkflowOpenApi();

[sfmskywalker]

Awesome 🎉

[Copilot]

Pull Request Overview

This PR introduces a new OpenAPI documentation extension for Elsa workflows that automatically generates API documentation for HTTP workflow triggers. The extension provides workflow-aware OpenAPI 3.0 specifications with interactive ReDoc interface.

Key changes:

• Automatic endpoint discovery from workflow definitions with HTTP triggers
• OpenAPI 3.0 JSON generation service with workflow metadata integration
• Interactive ReDoc UI accessible at /documentation endpoint

Reviewed Changes

Copilot reviewed 13 out of 14 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
WorkflowEndpointExtractor.cs	Extracts HTTP endpoints from workflows with metadata lookup
OpenApiGenerator.cs	Generates OpenAPI 3.0 JSON from endpoint definitions
ElsaVersionProvider.cs	Provides Elsa version detection from assembly attributes
EndpointDefinition.cs	Data model for HTTP endpoint with workflow metadata
Various extension files	Service registration, feature configuration, and endpoint mapping

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[sfmskywalker]

Awesome! 🚀