Crate matchit

MatchIt

A blazing fast URL router and path matcher.

use matchit::Node;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut matcher = Node::new();
    matcher.insert("/home", "Welcome!")?;
    matcher.insert("/users/:id", "A User")?;

    let matched = matcher.at("/users/978")?;
    assert_eq!(matched.params.get("id"), Some("978"));
    assert_eq!(*matched.value, "A User");

    Ok(())
}

Parameters

The matcher supports dynamic route segments. These are accessible by-name through the Params struct, which is returned on a successful match attempt.

A registered route can contain named or catch-all parameters.

Named Parameters

Named parameters like /:id match anything until the next / or the path end:

let mut m = Node::new();
m.insert("/users/:id", true)?;

assert_eq!(m.at("/users/1")?.params.get("id"), Some("1"));
assert_eq!(m.at("/users/23")?.params.get("id"), Some("23"));
assert!(m.at("/users").is_err());

Catch-all Parameters

Catch-all parameters start with * and match everything including the trailing slash. They must always be at the end of the route:

let mut m = Node::new();
m.insert("/*p", true)?;

assert_eq!(m.at("/")?.params.get("p"), Some("/"));
assert_eq!(m.at("/foo.js")?.params.get("p"), Some("/foo.js"));
assert_eq!(m.at("/c/bar.css")?.params.get("p"), Some("/c/bar.css"));

Routing Priority

Static and dynamic route segments are allowed to overlap. If they do, static segments will be given higher priority:

let mut m = Node::new();
m.insert("/home", "Welcome!").unwrap();  // priority: 1
m.insert("/about", "About Me").unwrap(); // priority: 1
m.insert("/:other", "...").unwrap();     // priority: 2

Catch-all parameters however are not allowed to overlap with other path segments. Attempting to insert a conflicting route will result in an error:

let mut m = Node::new();
m.insert("/home", "Welcome!").unwrap();

assert_eq!(
    m.insert("/*filepath", "..."),
    Err(InsertError::Conflict {
        with: "/home".into()
    })
);

How does it work?

Because URL paths follow a hierarchical structure, the matcher relies on a radix tree structure that makes heavy use of common prefixes:

Priority   Path             Value
9          \                1
3          ├s               None
2          |├earch\         2
1          |└upport\        3
2          ├blog\           4
1          |    └:post      None
1          |         └\     5
2          ├about-us\       6
1          |        └team\  7
1          └contact\        8

This allows us to reduce the route search to a small number of branches. Child nodes on the same level of the tree are also prioritized by the number of children with registered values, increasing the chance of choosing the correct branch of the first try.

Structs

Match

A successful match consisting of the registered value and the URL parameters, returned by Node::at.

MatchError

A failed match attempt, with trailing slash redirect information.

Node

A radix tree used for URL path matching.

Params

A list of parameters returned by a route match.

ParamsIter

An iterator over the keys and values of a route’s parameters.

Enums

InsertError

Represents errors that can occur when inserting a new route.