Canteen is the first project that I'm implementing in Rust. It's a clone of Flask, my very favorite Python web framework. There is code for an example implementation in the canteen-impl repository.

It's by no means complete, but I'm working on it, and it's now available on crates.io! To install and check it out, add the following to your Cargo.toml:

[dependencies]
canteen = "0.5"

The principle behind Canteen is simple -- handler functions are defined as simple Rust functions that take a Request and return a Response. Handlers are then attached to one or more routes and HTTP methods/verbs. Routes are specified using a simple syntax that lets you define variables within them; variables that can then be extracted to perform various operations. Currently, the following variable types can be used:

• <str:name> will match anything inside a path segment, returns a String
• <int:name> will return a signed integer (i32) from a path segment
  • ex: cnt.add_route("/api/foo/<int:foo_id>", &[Method::Get], my_handler) will match "/api/foo/123" but not "/api/foo/123.34" or "/api/foo/bar"
• <uint:name> will return an unsigned integer (u32)
• <float:name> does the same thing as the int parameter definition, but matches numbers with decimal points and returns an f32
• <path:name> will greedily take all path data contained, returns a String
  • ex: cnt.add_route("/static/<path:name>", &[Method::Get], utils::static_file) will serve anything in the /static/ directory as a file

After the handlers are attached to routes, the next step is to simply start the server. Any time a request is received, it is dispatched with the associated handler to a threadpool worker. The worker notifies the parent process when it's finished, and then the response is transmitted back to the client. Pretty straightforward stuff!

extern crate canteen;

use canteen::*;
use canteen::utils;

fn hello_handler(req: &Request) -> Response {
    let mut res = Response::new();

    res.set_status(200);
    res.set_content_type("text/plain");
    res.append("Hello, world!");

    res
}

fn double_handler(req: &Request) -> Response {
    let to_dbl: i32 = req.get("to_dbl");

    /* simpler response generation syntax */
    utils::make_response(format!("{}", to_dbl * 2), "text/plain", 200)
}

fn main() {
    let cnt = Canteen::new();

    // bind to the listening address
    cnt.bind(("127.0.0.1", 8080));

    // set the default route handler to show a 404 message
    cnt.set_default(utils::err_404);

    // respond to requests to / with "Hello, world!"
    cnt.add_route("/", &[Method::Get], hello_handler);

    // pull a variable from the path and do something with it
    cnt.add_route("/double/<int:to_dbl>", &[Method::Get], double_handler);

    // serve raw files from the /static/ directory
    cnt.add_route("/static/<path:path>", &[Method::Get], utils::static_file);

    cnt.run();
}