查看完整源代码 或 在线查看编译后的示例

此示例使用 fetch API 向 GitHub API 发出 HTTP 请求，然后解析结果 JSON。

Cargo.toml 启用了与 fetch API 和使用类型相关的许多功能：Headers、Request 等。

[package]
name = "fetch"
version = "0.1.0"
authors = ["The wasm-bindgen Developers"]
edition = "2018"
rust-version = "1.57"

[lib]
crate-type = ["cdylib"]

[dependencies]
wasm-bindgen = "0.2.92"
js-sys = "0.3.69"
wasm-bindgen-futures = "0.4.42"

[dependencies.web-sys]
version = "0.3.4"
features = [
  'Headers',
  'Request',
  'RequestInit',
  'RequestMode',
  'Response',
  'Window',
]

# #![allow(unused_variables)]
#fn main() {
use wasm_bindgen::prelude::*;
use wasm_bindgen_futures::JsFuture;
use web_sys::{Request, RequestInit, RequestMode, Response};

#[wasm_bindgen]
pub async fn run(repo: String) -> Result<JsValue, JsValue> {
    let mut opts = RequestInit::new();
    opts.method("GET");
    opts.mode(RequestMode::Cors);

    let url = format!("https://api.github.com/repos/{}/branches/master", repo);

    let request = Request::new_with_str_and_init(&url, &opts)?;

    request
        .headers()
        .set("Accept", "application/vnd.github.v3+json")?;

    let window = web_sys::window().unwrap();
    let resp_value = JsFuture::from(window.fetch_with_request(&request)).await?;

    // `resp_value` is a `Response` object.
    assert!(resp_value.is_instance_of::<Response>());
    let resp: Response = resp_value.dyn_into().unwrap();

    // Convert this other `Promise` into a rust `Future`.
    let json = JsFuture::from(resp.json()?).await?;

    // Send the JSON response back to JS.
    Ok(json)
}

#}