wren-server

A minimal HTTP server written in Wren.

Dependencies

• wren_cli 0.4.0
• Brian Otto's Recto string library (included in lib/Recto/)

System packages:

sudo apt-get install netcat      # for bin/wren-server (single-connection mode)
sudo apt-get install ucspi-tcp   # for bin/wren-tcpserver (concurrent mode)

Running the server

Two server modes are provided in bin/:

Single-connection (one request at a time, useful for development):

bin/wren-server

Uses a named pipe and netcat to loop indefinitely, handling one connection before accepting the next. All raw traffic is logged to log/inflow and log/outflow.

Concurrent (spawns a new process per connection):

bin/wren-tcpserver

Uses tcpserver from ucspi-tcp to accept multiple simultaneous connections.

Both modes listen on port 8080.

How it works

Each incoming HTTP request is piped to a fresh wren_cli server.wren process via stdin. The pipeline is:

Request → request.wren → router.wren → routes.wren → resource method → response.wren → Response

1. request.wren reads the request line and headers from stdin (terminating at the blank line), parses headers into a map, then reads the body up to Content-Length bytes using Stdin.readByte(). It exposes method, uri, route, headers, queryString, body, and params.

2. parameters.wren parses an application/x-www-form-urlencoded body into key/value pairs, with full URL decoding (+ → space, %XX → character). Access via params.get("key") or params.all.

3. routes.wren maps route strings (e.g. "POST /test") to resource method expressions (e.g. "TestResource.create()").

4. router.wren looks up the route, uses Meta.compileExpression() to evaluate the resource method string, runs it in a Fiber to catch errors, and responds with 200, 404, or 500 accordingly.

5. response.wren builds and writes the HTTP/1.0 response with status, headers, and body.

Current routes

Method	Path	Handler
GET	/	StatusResource.index()
GET	/test	TestResource.index()
POST	/test	TestResource.create()
GET	/test/new	TestResource.newForm()
GET	/test/1/edit	TestResource.edit()
PATCH	/test/1	TestResource.update()
DELETE	/test/1	TestResource.destroy()

Route IDs are currently hardcoded. Dynamic segment matching (:id) is not yet implemented.

Adding routes

Add an entry to the map in routes.wren and a corresponding static method on a resource class in router.wren:

// routes.wren
"GET /widgets": "WidgetResource.index()",

// router.wren
class WidgetResource {
  static index() {
    return "list of widgets"
  }
}

Testing

# Fire repeated POST requests
test/curler

# Load test with siege
test/bencher