route-to-openapi

Automatically scan route/endpoint definitions in source code and generate RESTful API documentation conforming to the OpenAPI 3.0.3 specification.

Supports major web frameworks with automatic framework detection. Extracts HTTP methods, paths, parameters, request bodies, response models, and doc comments, then outputs a standard OpenAPI spec file ready to import into Swagger UI or Redoc.

Quick Start

# Scan source directory, output OpenAPI spec in JSON format
python scripts/generate_api_doc.py ./src

# Specify output format and file
python scripts/generate_api_doc.py ./src --format yaml --output api-spec.yaml

# Specify framework and API metadata
python scripts/generate_api_doc.py ./app --framework flask --title "My API" --version 2.0.0

# Add server URLs
python scripts/generate_api_doc.py ./routes --server http://localhost:3000 --server https://api.example.com

Supported Frameworks

Language	Framework	Parsing Method
Python	Flask	AST parsing (decorators + type annotations + docstrings)
Python	FastAPI	AST parsing (decorators + Pydantic models + type annotations)
Python	Django REST Framework	AST parsing (@api_view decorators)
JavaScript/TypeScript	Express.js	Regex matching (app.get() / router.get() + JSDoc)
Go	Gin	Regex matching (r.GET() / group.GET() + comments)
Go	Echo	Regex matching (e.GET() + comments)

Extraction Capabilities

The script automatically extracts the following information:

• HTTP Methods: GET / POST / PUT / DELETE / PATCH, etc.
• Route Paths: Automatically converts each framework's path parameter format to the OpenAPI {param} format
• Path Parameters: Extracted from route patterns (with type inference)
• Query Parameters: Extracted from function signatures (Python frameworks)
• Request Bodies: Inferred from type annotations and Pydantic models (FastAPI)
• Response Models: Extracted from the response_model parameter (FastAPI)
• Endpoint Descriptions: Extracted from docstrings / JSDoc / inline comments
• Tag Grouping: Automatically grouped by source file module name

Path Parameter Format Conversion

Framework	Source Format	Converted Result
Flask	<int:user_id>	{user_id} (type: integer)
FastAPI	{user_id}	{user_id} (unchanged)
Express	:user_id	{user_id}
Gin/Echo	:user_id	{user_id}

Parameters

Parameter	Description	Default
source_dir	Source directory to scan (required)	-
-f, --format	Output format: json or yaml	json
-o, --output	Output file path	stdout
--framework	Force a specific framework (skip auto-detection)	Auto-detect
--title	API documentation title	API Documentation
--version	API version number	1.0.0
--description	API description text	Empty
--server	Server URL (can be specified multiple times)	None

Output Example

{
  "openapi": "3.0.3",
  "info": {
    "title": "My API",
    "version": "1.0.0"
  },
  "paths": {
    "/users": {
      "get": {
        "summary": "List all users",
        "operationId": "list_users",
        "tags": ["users"],
        "parameters": [
          {
            "name": "limit",
            "in": "query",
            "required": false,
            "schema": { "type": "integer" }
          }
        ],
        "responses": {
          "200": { "description": "Successful response" }
        }
      }
    },
    "/users/{user_id}": {
      "get": {
        "summary": "Get user by ID",
        "operationId": "get_user",
        "tags": ["users"],
        "parameters": [
          {
            "name": "user_id",
            "in": "path",
            "required": true,
            "schema": { "type": "integer" }
          }
        ],
        "responses": {
          "200": { "description": "Successful response" }
        }
      }
    }
  }
}

Prerequisites

• Python 3.8+
• No additional dependencies required — uses only the Python standard library
• The scanned project must use one of the supported web frameworks listed above