https://github.com/c-cube/tiny_httpd
Minimal HTTP server using good old threads + blocking IO, with a small request router.
https://github.com/c-cube/tiny_httpd
http httpd ocaml simplehttpserver threads tiny
Last synced: 3 months ago
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Minimal HTTP server using good old threads + blocking IO, with a small request router.
- Host: GitHub
- URL: https://github.com/c-cube/tiny_httpd
- Owner: c-cube
- Created: 2019-11-14T05:39:25.000Z (over 5 years ago)
- Default Branch: main
- Last Pushed: 2025-03-25T19:01:22.000Z (4 months ago)
- Last Synced: 2025-03-30T15:08:05.699Z (3 months ago)
- Topics: http, httpd, ocaml, simplehttpserver, threads, tiny
- Language: OCaml
- Homepage: https://c-cube.github.io/tiny_httpd
- Size: 7.6 MB
- Stars: 79
- Watchers: 5
- Forks: 12
- Open Issues: 8
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGES.md
Awesome Lists containing this project
README
# Tiny_httpd [](https://github.com/c-cube/tiny_httpd/actions)
Minimal HTTP server using good old threads, with stream abstractions,
simple routing, URL encoding/decoding, static asset serving,
and optional compression with camlzip.
It also supports [server-sent events](https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events)
([w3c](https://html.spec.whatwg.org/multipage/server-sent-events.html#event-stream-interpretation))
Free from all forms of `ppx`, async monads, etc. 🙃
**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`:
```ocaml
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
```
```sh
$ 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"}
```
## `http_of_dir`
Similar to `python -m http.server`, a simple program `http_of_dir` is provided.
It serves files from the current directory.
```sh
$ http_of_dir . -p 8080 &
$ curl -X GET http://localhost:8080
...
...
```
## Static assets and files
The program `http_of_dir` relies on the module `Tiny_httpd_dir`, which
can serve directories, as well as _virtual file systems_.
In 'examples/dune', we produce an OCaml module `vfs.ml` using
the program `tiny-httpd-vfs-pack`. This module contains a VFS (virtual file
system) which can be served as if it were an actual directory.
The dune rule:
```lisp
(rule
(targets vfs.ml)
(deps (source_tree files) (:out test_output.txt.expected))
(enabled_if (= %{system} "linux"))
(action (run ../src/bin/vfs_pack.exe -o %{targets}
--mirror=files/
--file=test_out.txt,%{out}
--url=example_dot_com,http://example.com)))
```
The code to serve the VFS from `vfs.ml` is as follows:
```ocaml
…
Tiny_httpd_dir.add_vfs server
~config:(Tiny_httpd_dir.config ~download:true
~dir_behavior:Tiny_httpd_dir.Index_or_lists ())
~vfs:Vfs.vfs ~prefix:"vfs";
…
```
it allows downloading the files, and listing directories.
If a directory contains `index.html` then this will be served
instead of listing the content.
## Steaming response body
Tiny_httpd provides multiple ways of returning a body in a response.
The response body type is:
```ocaml
type body =
[ `String of string
| `Stream of byte_stream
| `Writer of Tiny_httpd_io.Writer.t
| `Void ]
```
The simplest way is to return, say, `` `String "hello" ``. The response
will have a set content-length header and its body is just the string.
Some responses don't have a body at all, which is where `` `Void `` is useful.
The `` `Stream _ `` case is more advanced and really only intended for experts.
The `` `Writer w `` is new, and is intended as an easy way to write the
body in a streaming fashion. See 'examples/writer.ml' to see a full example.
Typically the idea is to create the body with `Tiny_httpd_io.Writer.make ~write ()`
where `write` will be called with an output channel (the connection to the client),
and can write whatever it wants to this channel. Once the `write` function returns
the body has been fully sent and the next request can be processed.
## Socket activation
Since version 0.10, socket activation is supported indirectly, by allowing a
socket to be explicitly passed in to the `create` function:
```ocaml
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](https://github.com/juergenhoetzel/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](http://0pointer.de/blog/projects/socket-activation.html) explains it
well.
## Why?
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.
## Documentation
See https://c-cube.github.io/tiny_httpd
## License
MIT.