Cataclysm. A simple rust http server

Work in progress: The work is completely unusable in its current state, but updates will come soon until a full HTTP/1.1 server is functional. This legend will be removed when such a state is reached.

Cataclysm is an http framework influenced by actix-web, and built over tokio. A minimal working example is the following

extern crate cataclysm;

use cataclysm::{Server, Branch, http::{Response, Method}};

async fn hello() -> Response {
    Response::ok().body("hello")
}

#[tokio::main]
async fn main() {
    let server = Server::builder(
        Branch::new("/hello").with(Method::Get.to(hello))
    ).build();

    server.run("localhost:8000").await.unwrap();
}

Closures as callbacks

Until async closures become stable, the option to pass closures as a path handler is with a closure that returns an async block

let server = Server::builder(
    Branch::new("/data").with(Method::Post.to(|data: Vec<u8>| async {
        // Do something with data
        // ...
        Response::ok().body("worked!")
    }))
).build();

Extractors

Some data can be retrieved from an http request by just adding arguments to the callback, with types that implement the Extractor trait. The default implementation list is the following

• String: Tries to extract the body as a valid utf-8 string. Returns Bad-Request if the operation fails
• Vec<u8>: Returns the content of the http call as a stream of bytes
• Request: Returns the request for a bit more control within the callback
• Path<T>: Returns the parameters from the path. T must be a tuple.

Layers

Cataclysm allows for layer handling, a.k.a. middleware.

let path = Branch::new("/hello")
    .with(Method::Get.to(world))
    .layer(|req: Request, pipeline: Box<Pipeline>| async {
        // Example of timing layer / middleware
        let now = std::time::Instant::now();
        // Execute the deeper layers of the pipeline
        let response = pipeline.execute(req).await;
        // Measure and print time
        let elapsed = now.elapsed().as_nanos();
        info!("Process time: {} ns", elapsed);
        // We return the request for further possible processing.
        request
}.boxed()).nested(Branch::new("/hola").with(Method::Delete.to(hello)));

As seen in the example, layer functions receive a Request and a boxed Pipeline enum. The Pipeline enum contains a nested structure of futures (the layers + the core handler), and has the execute to simplify things a bit. This function must return a Pin<Box<_>> future, so either use the boxed method from the FutureExt trait from the futures crate, or wrap it manually.

TODO

• Regex with / cause problems in branch creation (fix with queue implementation for "{", "}" detection)