#hyper #path #tree #radix #router

httprouter

A high performance HTTP request router that scales well

5 releases (breaking)

0.4.0 Mar 26, 2021
0.3.0 Mar 3, 2021
0.2.0 Dec 23, 2020
0.1.0 Dec 18, 2020
0.0.0 Nov 3, 2020

#30 in HTTP client

39 downloads per month

MIT license

46KB
454 lines

HttpRouter

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HttpRouter is a lightweight high performance HTTP request router.

This router supports variables in the routing pattern and matches against the request method. It also scales very well.

The router is optimized for high performance and a small memory footprint. It scales well even with very long paths and a large number of routes. A compressing dynamic trie (radix tree) structure is used for efficient matching. Internally, it uses the matchit package.

Features

Only explicit matches: With other routers, a requested URL path could match multiple patterns. Therefore they have some awkward pattern priority rules, like longest match or first registered, first matched. By design of this router, a request can only match exactly one or no route. As a result, there are also no unintended matches, which makes it great for SEO and improves the user experience.

Path auto-correction: Besides detecting the missing or additional trailing slash at no extra cost, the router can also fix wrong cases and remove superfluous path elements (like ../ or //). Is CAPTAIN CAPS LOCK one of your users? HttpRouter can help him by making a case-insensitive look-up and redirecting him to the correct URL.

Parameters in your routing pattern: Stop parsing the requested URL path, just give the path segment a name and the router delivers the dynamic value to you. Because of the design of the router, path parameters are very cheap.

High Performance: HttpRouter relies on a tree structure which makes heavy use of common prefixes, it is basically a radix tree. This makes lookups extremely fast. Internally, it uses the matchit package.

Of course you can also set custom NotFound and MethodNotAllowed handlers , serve static files, and automatically respond to OPTIONS requests

Usage

Here is a simple example:

use httprouter::{Router, Params};
use hyper::{Request, Response, Body, Error};

async fn index(_: Request<Body>) -> Result<Response<Body>, Error> {
    Ok(Response::new("Hello, World!".into()))
}

async fn hello(req: Request<Body>) -> Result<Response<Body>, Error> {
    let params = req.extensions().get::<Params>().unwrap();
    Ok(Response::new(format!("Hello, {}", params.get("user").unwrap()).into()))
}

#[tokio::main]
async fn main() {
    let router = Router::default()
        .get("/", index)
        .get("/hello/:user", hello);

    hyper::Server::bind(&([127, 0, 0, 1], 3000).into())
        .serve(router.into_service())
        .await;
}

Named parameters

As you can see, :user is a named parameter. The values are accessible via req.extensions().get::<Params>().

Named parameters only match a single path segment:

Pattern: /user/:user

 /user/gordon              match
 /user/you                 match
 /user/gordon/profile      no match
 /user/                    no match

Note: Since this router has only explicit matches, you can not register static routes and parameters for the same path segment. For example you can not register the patterns /user/new and /user/:user for the same request method at the same time. The routing of different request methods is independent from each other.

Catch-All parameters

The second type are catch-all parameters and have the form *name. Like the name suggests, they match everything. Therefore they must always be at the end of the pattern:

Pattern: /src/*filepath

 /src/                     match
 /src/somefile.go          match
 /src/subdir/somefile.go   match

Automatic OPTIONS responses and CORS

One might wish to modify automatic responses to OPTIONS requests, e.g. to support CORS preflight requests or to set other headers. This can be achieved using the Router::global_options handler:

use httprouter::Router;
use hyper::{Request, Response, Body, Error};

async fn cors(_: Request<Body>) -> Result<Response<Body>, Error> {
    let res = Response::builder()
        .header("Access-Control-Allow-Methods", "Allow")
        .header("Access-Control-Allow-Origin", "*")
        .body(Body::empty())
        .unwrap();
    Ok(res)
}

fn main() {
    let router = Router::default().global_options(cors);
}

Multi-domain / Sub-domains

Here is a quick example: Does your server serve multiple domains / hosts? You want to use sub-domains? Define a router per host!

use httprouter::Router;
use hyper::service::{make_service_fn, service_fn};
use hyper::{Body, Request, Response};
use std::collections::HashMap;
use std::convert::Infallible;
use std::sync::Arc;

pub struct HostSwitch<'a>(HashMap<String, Router<'a>>);

impl HostSwitch<'_> {
    async fn serve(&self, req: Request<Body>) -> hyper::Result<Response<Body>> {
        let forbidden = || Response::builder()
            .status(403)
            .body(Body::empty())
            .unwrap();
        match req.headers().get("host") {
            Some(host) => match self.0.get(host.to_str().unwrap()) {
                Some(router) => router.serve(req).await,
                None => Ok(forbidden()),
            },
            None => Ok(forbidden()),
        }
    }
}

#[tokio::main]
async fn main() {
    let mut host_switch = HostSwitch(HashMap::new());
    host_switch.0.insert("example.com:12345".into(), Router::default());

    let host_switch = Arc::new(host_switch);
    
    let make_svc = make_service_fn(move |_| {
        let host_switch = host_switch.clone();
        async move {
            Ok::<_, Infallible>(service_fn(move |req| {
                let host_switch = host_switch.clone();
                async move { host_switch.serve(req).await }
            }))
        }
    });

    hyper::Server::bind(&([127, 0, 0, 1], 3000).into())
        .serve(make_svc)
        .await;
}

Not Found Handler

NOTE: It might be required to set Router::method_not_allowed to None to avoid problems.

You can use another handler, to handle requests which could not be matched by this router by using the Router::not_found handler.

The not_found handler can for example be used to return a 404 page:

use httprouter::Router;
use hyper::{Request, Response, Body, Error};

async fn not_found(req: Request<Body>) -> Result<Response<Body>, Error> {
    let res = Response::builder()
	    .status(404)
	    .body(Body::empty())
	    .unwrap();
    Ok(res)
}

fn main() {
    let router = Router::default().not_found(not_found);
}

Static files

You can use the router to serve pages from a static file directory:

// TODO

Dependencies

~5MB
~94K SLoC