HTTP Endpoints

Comparable to: Express, Fastify, Flask

Key Concepts

Use the concepts below when they fit the task. Not every HTTP endpoint needs all of them.

• Each route is a registered function bound to a path and method via an HTTP trigger
• The handler receives an ApiRequest object containing body, path_params, headers, and method
• Handlers return { status_code, body, headers } to shape the HTTP response
• RestApiModule serves all registered routes on port 3111
• Path parameters use colon syntax (e.g. /users/:id) and arrive in path_params
• Middleware can run before handlers via middleware_function_ids in the trigger config — see iii-http-middleware for details

Architecture

HTTP request
  → RestApiModule (port 3111)
    → registerTrigger route match (method + path)
      → registerFunction handler (receives ApiRequest)
        → { status_code, body, headers } response

iii Primitives and HTTP Trigger Config Used

Reference Implementation

See ../references/http-endpoints.js for the full working example — a REST API with parameterized routes handling GET and POST requests.

Also available in Python: ../references/http-endpoints.py

Also available in Rust: ../references/http-endpoints.rs

Common Patterns

Code using this pattern commonly includes, when relevant:

• registerWorker(url, { workerName }) — worker initialization
• registerFunction(id, handler) — define the route handler
• registerTrigger({ type: 'http', config: { api_path, http_method } }) — bind path and method
• req.body — parsed request body for POST/PUT
• req.path_params — extracted path parameters
• return { status_code: 200, body: { data }, headers: { 'Content-Type': 'application/json' } } — response shape
• const logger = new Logger() — structured logging per handler

Adapting This Pattern

Use the adaptations below when they apply to the task.

• Add more routes by registering additional functions and HTTP triggers with distinct paths or methods
• Use path_params for resource identifiers (e.g. /orders/:orderId)
• Return appropriate status codes (201 for creation, 404 for not found, 400 for bad input)
• For authenticated routes, use middleware (middleware_function_ids) or inspect req.headers for tokens or API keys
• Chain work behind an endpoint by enqueuing to a queue after returning a 202 Accepted
• For reusable auth, logging, or rate-limiting before handlers, prefer iii-http-middleware

Pattern Boundaries

• If the task is about calling external HTTP APIs from iii functions, prefer iii-http-invoked-functions.
• If async processing is needed behind the endpoint, prefer iii-queue-processing for the background work.
• If the task is specifically about middleware chains (auth, logging, rate-limiting), prefer iii-http-middleware.
• Stay with iii-http-endpoints when iii owns the route and handles the inbound request directly.

When to Use

• Use this skill when the task is primarily about iii-http-endpoints in the iii engine.
• Triggers when the request directly asks for this pattern or an equivalent implementation.

Boundaries

• Never use this skill as a generic fallback for unrelated tasks.
• You must not apply this skill when a more specific iii skill is a better fit.
• Always verify environment and safety constraints before applying examples from this skill.