Build a FastEdge HTTP application

FastEdge HTTP applications respond to HTTP requests directly from the edge. The handler compiles to a WebAssembly binary and runs without servers or containers. Three language options are available — complete the toolchain setup first: Rust (Modern HTTP), Rust (Legacy HTTP), or JavaScript.

Write a handler

Each language uses a different entry point convention. Choose the tab that matches the toolchain set up earlier.

Modern Rust
Legacy Rust
JavaScript

Replace src/lib.rs with:

use wstd::http::body::Body;
use wstd::http::{Request, Response};

#[wstd::http_server]
async fn main(request: Request<Body>) -> anyhow::Result<Response<Body>> {
    let url = request.uri().to_string();
    Ok(Response::builder()
        .status(200)
        .header("content-type", "text/plain;charset=UTF-8")
        .body(Body::from(format!("Request received: {url}")))?)
}

Replace src/lib.rs with:

use fastedge::body::Body;
use fastedge::http::{Request, Response, StatusCode, Error};

#[fastedge::http]
fn main(request: Request<Body>) -> Result<Response<Body>, Error> {
    let url = request.uri().to_string();
    Response::builder()
        .status(StatusCode::OK)
        .header("content-type", "text/plain;charset=UTF-8")
        .body(Body::from(format!("Request received: {url}")))
}

Create src/index.js:

addEventListener('fetch', (event) => {
  const url = event.request.url;
  event.respondWith(new Response(`Request received: ${url}`));
});

Build

Compile the handler to a WebAssembly binary. The first build downloads dependencies and takes one to two minutes.

Modern Rust
Legacy Rust
JavaScript

cargo build --release --target wasm32-wasip2

The binary is at ./target/wasm32-wasip2/release/hello_world.wasm.

cargo build --release --target wasm32-wasip1

The binary is at ./target/wasm32-wasip1/release/hello_world.wasm.

npx fastedge-build --input src/index.js --output wasm/app.wasm

The binary is at ./wasm/app.wasm.

Deploy

Geolocation redirect Call an external API

⌘I

​Write a handler

​Build

​Deploy

Write a handler

Build

Deploy