Minimal HTTP server using good old threads, with stream abstractions, simple routing, URL encoding/decoding, and optional compression with camlzip. It also supports server-sent events (w3c)
Free from all forms of ppx
, async monads, etc. ๐
Note: it can be useful to add the jemalloc
opam package for long running
server, as it does a good job at controlling memory usage.
The basic echo server from src/examples/echo.ml
:
module S = Tiny_httpd
let () =
let server = S.create () in
(* say hello *)
S.add_route_handler ~meth:`GET server
S.Route.(exact "hello" @/ string @/ return)
(fun name _req -> S.Response.make_string (Ok ("hello " ^name ^"!\n")));
(* echo request *)
S.add_route_handler server
S.Route.(exact "echo" @/ return)
(fun req -> S.Response.make_string (Ok (Format.asprintf "echo:@ %a@." S.Request.pp req)));
Printf.printf "listening on http://%s:%d\n%!" (S.addr server) (S.port server);
match S.run server with
| Ok () -> ()
| Error e -> raise e
$ dune exec src/examples/echo.exe &
listening on http://127.0.0.1:8080
# the path "hello/name" greets you.
$ curl -X GET http://localhost:8080/hello/quadrarotaphile
hello quadrarotaphile!
# the path "echo" just prints the request.
$ curl -X GET http://localhost:8080/echo --data "howdy y'all"
echo:
{meth=GET;
headers=Host: localhost:8080
User-Agent: curl/7.66.0
Accept: */*
Content-Length: 10
Content-Type: application/x-www-form-urlencoded;
path="/echo"; body="howdy y'all"}
Similar to python -m http.server
, a simple program http_of_dir
is provided.
It serves files from the current directory.
$ http_of_dir . -p 8080 &
$ curl -X GET http://localhost:8080
...
<html list of current dir>
...
Since version 0.10, socket activation is supported indirectly, by allowing a
socket to be explicitly passed in to the create
function:
module S = Tiny_httpd
let not_found _ _ = S.Response.fail ~code:404 "Not Found\n"
let () =
(* Module [Daemon] is from the [ocaml-systemd] package *)
let server = match Daemon.listen_fds () with
(* If no socket passed in, assume server was started explicitly i.e. without
socket activation *)
| [] -> S.create ()
(* If a socket passed in e.g. by systemd, listen on that *)
| sock :: _ -> S.create ~sock ()
in
S.add_route_handler server S.Route.rest_of_path not_found;
Printf.printf "Listening on http://%s:%d\n%!" (S.addr server) (S.port server);
match S.run server with
| Ok () -> ()
| Error e -> raise e
On Linux, this requires the ocaml-systemd package:
opam install ocaml-systemd
Tip: in the dune
file, the package name should be systemd
.
In case you're not familiar with socket activation, Lennart Poettering's blog post explains it well.
Why not? If you just want a super basic local server (perhaps for exposing data from a local demon, like Cups or Syncthing do), no need for a ton of dependencies or high scalability libraries.
Use cases might include:
- serve content directly from a static blog generator;
- provide a web UI to some tool (like CUPS and syncthing do);
- implement a basic monitoring page for a service;
- provide a simple json API for a service, on top of http;
- use
http_of_dir
to serve odoc-generated docs or some assets directory.
See https://c-cube.github.io/tiny_httpd
MIT.