Axum HTTP tracker: basic scaffolding

[josecelano]

This is the first of a series of PR associated with the issue #160

We are changing the HTTP tracker to use Axum instead of Warp. This PR allows:

• Running full Warp implementation in production while enabling new implementation.
• Running both implementations for testing while implementing the new Axum version.

It also allows parsing the URL query params for the announce query. For the time being, only the mandatory params.

The announce request URL has two parameters that contain binary data (20 bytes).

Sample Announce URL:

http://0.0.0.0:7070/announce?info_hash=%3B%24U%04%CF%5F%11%BB%DB%E1%20%1C%EAjk%F4Z%EE%1B%C0&peer_id=-qB00000000000000001&port=17548

The "infohash" and "peer id" cannot be extracted using the generic Axum Query extractor because it cannot parse binary data. As you can read here.

I could have used the RawQuery extractor, but I thought this way would be much cleaner because you can pass the AnnounceParams into the handler like this:

pub async fn announce_handler(
    State(_tracker): State<Arc<Tracker>>,
    ExtractAnnounceParams(_announce_params): ExtractAnnounceParams,
) -> Json<Ok> {
    todo!()
}

And you can also handle the errors in the extractor if you have to return a "bad request" response. Alternatively, I could have handled parsing and error handling inside the handler.

[da2ce7]

ACK 995397e

[da2ce7]

Looks Good