esi

A streaming Edge Side Includes parser and executor designed for Fastly Compute@Edge.

The implementation is currently a subset of the ESI Language Specification 1.0, supporting the following tags:

• <esi:include> (+ alt, onerror="continue")
• <esi:comment>
• <esi:remove>

Other tags will be ignored.

Example Usage

use esi::Processor;
use fastly::{http::StatusCode, mime, Error, Request, Response};

fn main() {
    if let Err(err) = handle_request(Request::from_client()) {
        println!("returning error response");

        Response::from_status(StatusCode::INTERNAL_SERVER_ERROR)
            .with_body(err.to_string())
            .send_to_client();
    }
}

fn handle_request(req: Request) -> Result<(), Error> {
    // Fetch ESI document from backend.
    let beresp = req.clone_without_body().send("origin_0")?;

    // Construct an ESI processor with the default configuration.
    let config = esi::Configuration::default();
    let processor = Processor::new(config);

    // Execute the ESI document using the client request as context
    // and sending all requests to the backend `origin_1`.
    processor.execute_esi(req, beresp, &|req| {
        Ok(req.with_ttl(120).send("origin_1")?)
    })?;

    Ok(())
}

See a full example app in the esi_example_app subdirectory, or read the hosted documentation at docs.rs/esi.

License

The source and documentation for this project are released under the MIT License.