README.md

HTTP Hello World

Your first Wippy HTTP application — a minimal web API with one endpoint.

GET /hello → {"message": "hello world"}

Architecture

HTTP request
│
▼
gateway (http.service :8080)
│
▼
api (http.router, prefix: /)
│
▼
hello.endpoint (GET /hello)
│
▼
hello (function.lua) → {"message": "hello world"}

Four entries work together:

1. gateway — HTTP server listening on port 8080
2. api — Router attached to gateway via meta.server
3. hello — Lua function that handles requests
4. hello.endpoint — Routes GET /hello to the function

Project Structure

http-hello-world/
├── wippy.lock
└── src/
    ├── _index.yaml      # 4 entries: server, router, function, endpoint
    └── hello.lua         # Handler: returns JSON

Registry Entries

Entry	Kind	Purpose
app:gateway	http.service	HTTP server on :8080
app:api	http.router	Route dispatcher (prefix: /)
app:hello	function.lua	Handler function
app:hello.endpoint	http.endpoint	Maps GET /hello to handler

Running

cd examples/http-hello-world
wippy run

Test:

curl http://localhost:8080/hello

Response:

{"message":"hello world"}

Key Concepts

• http.service — declares an HTTP server with an address. auto_start: true starts it with wippy run.
• http.router — attaches to a server via meta.server: gateway. Routes requests by path prefix.
• http.endpoint — maps an HTTP method + path to a function.lua handler. Links to router via meta.router.
• function.lua — stateless handler. Uses http.response() to build the response. No request parsing needed for this simple case.
• res:set_status() then res:write_json() — response methods must be called separately (chaining doesn't work because set_status() doesn't return res).