Serve HTTP

A web server in cljgo is a function. It receives a request as a map and returns a response as a map. That’s the entire model — everything else is detail.

Start small: the smallest server

(require '[cljg.http :as http])

(http/serve {:port 8080
             :handler (fn [req]
                        {:status 200
                         :body   "Hello from my first server!"})})

Visit http://localhost:8080:

Hello from my first server!

Read the serve call with page 3 eyes: it’s one options map — :port, and a :handler function. The handler ignores the request and always answers the same thing.

Look at the request

The request is a plain map. Pull out :uri to see what was asked for:

(http/serve {:port 8080
             :handler (fn [req]
                        {:status 200
                         :body   (str "you asked for " (:uri req))})})

Now http://localhost:8080/fruit/mango answers:

you asked for /fruit/mango

No router yet, no annotations, no framework — just reading a key from a map.

Put it together: test your server from code

:port 0 means “pick any free port” — perfect for tests. The returned server tells you where it landed, and stop shuts it down gracefully:

(require '[cljg.net.http :as client])

(def server
  (http/serve {:port 0
               :handler (fn [req] {:status 200 :body "pong"})}))

(def reply (client/get (str "http://127.0.0.1:" (:port server))))

(:status reply)
(:body reply)

Output:

200
pong

(http/stop server)

Server up, request made, answer checked, server down — in one file, no tools outside cljgo.

When you want routing, middleware, HTML and auth on top of this primitive, that’s the bri framework — built on exactly this serve.