jjpe/fetch-rs

fetch-rs

This crate is a Foreign Function Interface (FFI) that allows Rust code to call the JavaScript fetch API when deployed on WASM.

The main differences between this crate and using the web_sys-provided version of the fetch API directly are:

1. The web_sys-provided version only works in the browser. It will compile when targeting NodeJS, but will fail at runtime.
2. Ergonomics. The web_sys version is not very rusty, while this crate aims to be.

Usage

NOTE Keep in mind that:

• This crate is only usable on WASM. This means that any crate that uses fetch-rs will stop compiling to native code.
• Because the fetch API is inherently async, so is this API. This property is infectious, meaning that any code using this crate would to well to convert to async as well.
• There are limitations that are imposed by virtue of depending on the node-fetch NPM package. See the NPM page for more details on that.

preparation

If you aim to test code using e.g. NodeJS or the browser, install wasm-pack by executing cargo install wasm-pack.

Cargo.toml

Add this to your Cargo.toml:

[dependencies]
fetch-rs = "0.1"

Create and send request

1. GET-request:

use fetch_rs::Request;

#[wasm_bindgen] // <-- This makes the fn callable from JavaScript for easy testing
pub async fn perform_get_request(url: String) -> JsValue {
    let result: JsValue = Request::get(&url)
        .fetch_text() // fetch the result as text
        .await;
    info!("[test] result: {:?}", result); // Write test output
    result // Since the fn is async, return a Promise / Future
}

2. POST-request:

use fetch_rs::Request;

#[wasm_bindgen] // <-- This makes the fn callable from JavaScript for easy testing
pub async fn perform_post_request(url: String) -> JsValue {
    let result: JsValue = Request::post(&url)
    .fetch_text() // fetch the result as text
    .await;
    info!("[test] result: {:?}", result); // Write test output
    result // Since the fn is async, return a Promise / Future
}

For more examples, check out the examples module in the src directory.