Get Route/Path name from function to be used for logging

[roshanjrajan]

Hi! I was wondering if it is possible to extract the path name to be used for logging purposes. I have many of these created but wanted to keep track of what requests are hit the most. Is there a way to get this information? I am looking to get the string "/api/endpoint1" in the example below.

#[get("/api/endpoint1")] 
async fn api_request() -> Result<String> {
    Ok(String::from("Hello World"))
}

[robjtede]

#[get("/api/endpoint1")] 
async fn api_request(req: HttpRequest) -> Result<String> {
    let path = req.path();
    ...
}

For logging, there's a built in Logger middleware (search docs).

[roshanjrajan]

Thanks for the response @robjtede. I was able to find match_pattern() which works better for my use case! But I was hitting this issue where I was trying to get match_pattern() on ServiceRequest, but would keep getting None. I tried putting the wrap_fn before and after my .service calls (looks like below). I can see this info populated when checking in the HttpRequest handler but wanted to create a generic logging handler in wrap_fn. Is there anything that I can do here?

App::new()
.wrap_fn(|req, srv| {
	let path = req.match_pattern() // Returns None
    ...
}
.service(a)
.service(b)
.wrap_fn(|req, srv| {
	let path = req.match_pattern() // Also returns None
    ...
}

[robjtede]

Firstly, your code sample is equivalent to the following. See that the order of the service calls relative to the wrap_fn calls does not matter.

App::new()
.wrap_fn(|req, srv| {
	let path = req.match_pattern() // Returns None
    ...
}
.wrap_fn(|req, srv| {
	let path = req.match_pattern() // Also returns None
    ...
}
.service(a)
.service(b)

However, the reason you're seeing None is because there is no routing info at this level in the middleware. Middleware wrap the router so the pre-router section of a middleware function has no knowledge of the router itself. If you try to get this info after srv.call(req) then you'll see match_pattern be populated correctly. (This needs documenting better.)

[roshanjrajan]

Thank you for the quick response @robjtede! That makes much more sense!
But I am struggling on 1 thing. I don't fully understand how I can access req after the srv.call(req)? I'm assuming I need to clone it but I can't clone the HttpRequest as it is private, ServiceRequest doesn't implement Clone, and I can't break the object using into_parts() and reconstruct it using from_parts() because of the constraints on the counter. Is there another way to get this information? Or do I need to create a middleware similar to the one done for Logger?

[robjtede]

https://docs.rs/actix-web/latest/actix_web/dev/struct.ServiceResponse.html#method.request

[roshanjrajan]

Exactly what I am looking for! Thank you so much for your help!