hyper_method_override_middleware/
lib.rs

1//! A middleware that overrides an incoming POST request with a method given in
2//! the request's `_method` query paramerter. This is useful as web browsers
3//! typically only support GET and POST requests, but our application may
4//! expect other HTTP methods that are more semantically correct.
5//!
6//! The methods PUT, PATCH, and DELETE are accepted for overriding, all others
7//! are ignored.
8//!
9//! The `_method` query paramerter can be specified in a HTML form like so:
10//!
11//!    <form method="POST" action="/item/1?_method=DELETE">
12//!      <button type="submit">Delete item</button>
13//!    </form>
14//!
15
16use hyper::{service::Service, Method, Request};
17use std::borrow::Borrow;
18use std::task::{Context, Poll};
19use url::form_urlencoded;
20
21#[derive(Debug, Clone)]
22pub struct MethodOverrideMiddleware<T> {
23    inner_service: T,
24}
25
26impl<T> MethodOverrideMiddleware<T> {
27    pub fn new(inner_service: T) -> Self {
28        Self { inner_service }
29    }
30}
31
32impl<InnerService, Body> Service<Request<Body>> for MethodOverrideMiddleware<InnerService>
33where
34    InnerService: Service<Request<Body>>,
35{
36    type Response = InnerService::Response;
37    type Error = InnerService::Error;
38    type Future = InnerService::Future;
39
40    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
41        self.inner_service.poll_ready(cx)
42    }
43
44    fn call(&mut self, mut req: Request<Body>) -> Self::Future {
45        if let Some(new_method) = override_method(&req) {
46            *req.method_mut() = new_method;
47        }
48        self.inner_service.call(req)
49    }
50}
51
52fn override_method<Body>(req: &Request<Body>) -> Option<Method> {
53    if req.method() != &Method::POST {
54        return None;
55    }
56
57    form_urlencoded::parse(req.uri().query().unwrap_or("").as_bytes())
58        .find(|(param_name, _)| param_name == "_method")
59        .and_then(|(_, method)| match method.borrow() {
60            "DELETE" => Some(Method::DELETE),
61            "PATCH" => Some(Method::PATCH),
62            "PUT" => Some(Method::PUT),
63            _ => None,
64        })
65}
66
67#[cfg(test)]
68mod tests {
69    use super::*;
70    use hyper::service::{make_service_fn, service_fn};
71    use hyper::{Body, Request, Response, Server};
72    use std::convert::Infallible;
73
74    async fn handle(req: Request<Body>) -> Result<Response<Body>, Infallible> {
75        let body = format!("{:?}", req.method()).into();
76        Ok(Response::new(body))
77    }
78
79    async fn send(method: Method, url: &str) -> String {
80        reqwest::Client::new()
81            .execute(reqwest::Request::new(
82                method,
83                reqwest::Url::parse(url).unwrap(),
84            ))
85            .await
86            .unwrap()
87            .text()
88            .await
89            .unwrap()
90    }
91
92    #[tokio::test]
93    async fn override_test() {
94        let addr = ([127, 0, 0, 1], 1337).into();
95
96        tokio::spawn(Server::bind(&addr).serve(make_service_fn(|_| async {
97            let service = MethodOverrideMiddleware::new(service_fn(handle));
98            Ok::<_, hyper::Error>(service)
99        })));
100
101        // No override requested
102        assert_eq!(send(Method::GET, "http://127.0.0.1:1337").await, "GET");
103        assert_eq!(send(Method::PUT, "http://127.0.0.1:1337").await, "PUT");
104        assert_eq!(send(Method::POST, "http://127.0.0.1:1337").await, "POST");
105        assert_eq!(send(Method::PATCH, "http://127.0.0.1:1337").await, "PATCH");
106
107        // Successful overrides
108        assert_eq!(
109            send(Method::POST, "http://127.0.0.1:1337?a=1&b=2&_method=PATCH").await,
110            "PATCH"
111        );
112        assert_eq!(
113            send(Method::POST, "http://127.0.0.1:1337?a=1&b=2&_method=PUT").await,
114            "PUT"
115        );
116        assert_eq!(
117            send(Method::POST, "http://127.0.0.1:1337?a=1&b=2&_method=DELETE").await,
118            "DELETE"
119        );
120
121        // Other methods cannot be specified for overrides
122        assert_eq!(
123            send(Method::POST, "http://127.0.0.1:1337?a=1&b=2&_method=GET").await,
124            "POST"
125        );
126        assert_eq!(
127            send(Method::POST, "http://127.0.0.1:1337?_method=OPTIONS").await,
128            "POST"
129        );
130
131        // Non-POST requests don't get overriden
132        assert_eq!(
133            send(Method::GET, "http://127.0.0.1:1337?_method=PATCH").await,
134            "GET"
135        );
136        assert_eq!(
137            send(Method::DELETE, "http://127.0.0.1:1337?_method=PUT").await,
138            "DELETE"
139        );
140        assert_eq!(
141            send(Method::PATCH, "http://127.0.0.1:1337?_method=DELETE").await,
142            "PATCH"
143        );
144    }
145}
hyper_method_override_middleware/lib.rs

hyper_method_override_middleware/
lib.rs
