GET parameter with fixed values

TODO!

[package]
name = "versioning"
version = "0.1.0"
edition = "2024"
publish = false

[dependencies]
axum = "0.8.8"
mime = "0.3.17"
serde = { version = "1.0.228", features = ["derive"] }
tokio = { version = "1.50.0", features = ["full"] }
tracing = "0.1.44"
tracing-subscriber = { version = "0.3.23", features = ["env-filter"] }

[dev-dependencies]
headers = "0.4.1"
http-body-util = "0.1.3"
tower = { version = "0.5.3", features = ["util"] }

Code

use axum::{
    RequestPartsExt, Router,
    extract::{FromRequestParts, Path},
    http::{StatusCode, request::Parts},
    response::{Html, IntoResponse, Response},
    routing::get,
};
use std::collections::HashMap;

async fn main_page() -> Html<&'static str> {
    Html(
        r#"
        <a href="/api/v1/status">v1</a><br>
        <a href="/api/v2/status">v2</a><br>
        <a href="/api/v3/status">v3</a><br>
        <a href="/api/v4/status">v4</a><br>
    "#,
    )
}

#[derive(Debug)]
enum Version {
    V1,
    V2,
    V3,
}

impl<S> FromRequestParts<S> for Version
where
    S: Send + Sync,
{
    type Rejection = Response;

    async fn from_request_parts(parts: &mut Parts, _state: &S) -> Result<Self, Self::Rejection> {
        let params: Path<HashMap<String, String>> =
            parts.extract().await.map_err(IntoResponse::into_response)?;

        let version = params
            .get("version")
            .ok_or_else(|| (StatusCode::NOT_FOUND, "version param missing").into_response())?;

        match version.as_str() {
            "v1" => Ok(Version::V1),
            "v2" => Ok(Version::V2),
            "v3" => Ok(Version::V3),
            _ => Err((StatusCode::NOT_FOUND, "unknown version").into_response()),
        }
    }
}

async fn handle_api(version: Version) -> Html<String> {
    Html(format!("received request with version {version:?}"))
}

fn create_router() -> Router {
    Router::new()
        .route("/", get(main_page))
        .route("/api/{version}/status", get(handle_api))
}

#[tokio::main]
async fn main() {
    let app = create_router();

    let listener = tokio::net::TcpListener::bind("127.0.0.1:3000")
        .await
        .unwrap();
    println!("listening on {}", listener.local_addr().unwrap());
    axum::serve(listener, app).await.unwrap();
}

#[cfg(test)]
mod tests;

Tests

#![allow(unused)]
fn main() {
use axum::{body::Body, http::Request, http::StatusCode};
use http_body_util::BodyExt;
use tower::ServiceExt;

use super::*;

#[tokio::test]
async fn test_v1() {
    let response = create_router()
        .oneshot(
            Request::builder()
                .uri("/api/v1/status")
                .body(Body::empty())
                .unwrap(),
        )
        .await
        .unwrap();

    assert_eq!(response.status(), StatusCode::OK);
    let body = response.into_body();
    let bytes = body.collect().await.unwrap().to_bytes();
    let html = String::from_utf8(bytes.to_vec()).unwrap();

    assert_eq!(html, "received request with version V1");
}

#[tokio::test]
async fn test_v4() {
    let response = create_router()
        .oneshot(
            Request::builder()
                .uri("/api/v4/status")
                .body(Body::empty())
                .unwrap(),
        )
        .await
        .unwrap();

    assert_eq!(response.status(), StatusCode::NOT_FOUND);
    let body = response.into_body();
    let bytes = body.collect().await.unwrap().to_bytes();
    let html = String::from_utf8(bytes.to_vec()).unwrap();

    assert_eq!(html, "unknown version");
}
}