iron-pipeline

Simple pipelined request handler for the Iron framework. Inspired by similar APIs used in the new ASP.NET Core 1.0 framework, which in turn is inspired by Microsoft's OWIN implementation, node.js and other web frameworks.

Documentation

API documentation can be found here.

About

Under iron-pipeline every request is sent through a daisy chain of middlewares, each of which may optionally:

Create and return a response
Modify the request
Delegate to the next middleware in the pipeline
Modify the response created by another middleware

Unlike Chain, middleware is always executed in the exact order in which it was registered. Also unlike Chain, there is only one middleware trait: Middleware.

The Middleware trait

The Middleware trait is implemented for any middleware you want to run in a pipeline.

The trait is nearly identical in behaviour to the iron::middleware::Handler trait as it accepts an &mut Request and returns an IronResult<Response>. However it also accepts a PipelineNext parameter, which allows it to optionally invoke the next middleware in the pipeline.

For example, a simple HTTPS redirect middleware:

struct HttpsRedirect;

impl Middleware for HttpsRedirect {
    fn process(&self, req: &mut Request, next: PipelineNext) -> IronResult<Response> {
        if req.url.scheme != "https" {
            // Redirect non-https requests to the https version of this endpoint
            let url = make_https_url(&req.url);
            return Ok(Response::with((status::PermanentRedirect, Location(url))));
        }
        // Allow all other middleware to process the request
        next.process(req)
    }
}

Additionally, Middleware is automatically implemented for all types which implement Handler so you can easily add other Iron-compatible handlers like Router to your pipeline.

Note: Because the Handler trait cannot invoke the next middleware, it is generally only useful to put such handlers at the end of a pipeline or sub-pipeline.

Examples

See the examples directory.

You can run the examples with the cargo run --example command, e.g.

$ cargo run --example complex

Usage

This crate may be used by adding iron-pipeline to the dependencies in your project's Cargo.toml:

[dependencies]
iron-pipeline = { git = "https://github.com/deadalusai/iron-pipeline" }

and the following to your crate root:

extern crate iron_pipeline;