Making Requests

Recipe	Crates	Categories
Make a HTTP GET request
Set custom headers and URL parameters for a REST request
Async

Make a HTTP GET request

Parses the supplied URL and makes a synchronous HTTP GET request with reqwest::blocking::get⮳ Prints obtained reqwest::blocking::Response⮳ status and headers. Reads HTTP response body into an allocated std::string::String⮳ using std::io::Read::read_to_string⮳.

use std::io::Read;

use anyhow::Result;

fn main() -> Result<()> {
    let mut res = reqwest::blocking::get("http://httpbin.org/get")?;
    let mut body = String::new();
    res.read_to_string(&mut body)?;

    println!("Status: {}", res.status());
    println!("Headers:\n{:#?}", res.headers());
    println!("Body:\n{}", body);

    Ok(())
}

Async

A similar approach can be used by including the tokio⮳ executor to make the main function asynchronous, retrieving the same information.

In this example, tokio::main⮳ handles all the heavy executor setup and allows sequential code implemented without blocking until .await.

Uses the asynchronous versions of reqwest⮳, both reqwest::get⮳ and reqwest::Response⮳.

use anyhow::Result;

#[tokio::main]
async fn main() -> Result<()> {
    let res = reqwest::get("http://httpbin.org/get").await?;
    println!("Status: {}", res.status());
    println!("Headers:\n{:#?}", res.headers());

    let body = res.text().await?;
    println!("Body:\n{}", body);
    Ok(())
}

Set custom headers and URL parameters for a REST request

Sets both standard and custom HTTP headers as well as URL parameters for a HTTP GET request. Creates a custom header of type XPoweredBy with hyper::header!⮳ macro.

Builds complex URL with url::Url::parse_with_params⮳. Sets standard headers hyper::header::USER_AGENT⮳ hyper::header::AUTHORIZATION⮳ and custom XPoweredBy with reqwest::RequestBuilder::header⮳, then makes the request with reqwest::RequestBuilder::send⮳.

The request targets http://httpbin.org/headers service which responds with a JSON dict containing all request headers for easy verification.

use std::collections::HashMap;

use anyhow::Result;
use reqwest::header;
use serde::Deserialize;

#[derive(Deserialize, Debug)]
pub struct HeadersEcho {
    pub headers: HashMap<String, String>,
}

fn main() -> Result<()> {
    // Parse an absolute URL from a string and add params to its query string
    let url = url::Url::parse_with_params(
        "http://httpbin.org/headers",
        &[("lang", "rust"), ("browser", "servo")],
    )?;

    // Define default headers for all requests
    let mut default_headers = header::HeaderMap::new();
    default_headers
        .insert("X-MY-HEADER", header::HeaderValue::from_static("value"));

    let client = reqwest::blocking::Client::builder()
        .user_agent("Rust-test")
        .default_headers(default_headers)
        .build()?;

    // Headers for this request only
    let mut headers = header::HeaderMap::new();
    headers.insert(
        reqwest::header::CONTENT_TYPE,
        header::HeaderValue::from_static("image/png"),
    );

    let response = client.get(url)
        .headers(headers)
        .bearer_auth("DEadBEEfc001cAFeEDEcafBAd") // Enable HTTP bearer authentication.
        .send()?;

    assert_eq!(
        response.url().as_str(),
        "http://httpbin.org/headers?lang=rust&browser=servo"
    );

    let out: HeadersEcho = response.json()?;
    assert_eq!(
        out.headers["Authorization"],
        "Bearer DEadBEEfc001cAFeEDEcafBAd"
    );
    assert_eq!(out.headers["User-Agent"], "Rust-test");
    assert_eq!(out.headers["X-My-Header"], "value");
    println!("{:?}", out);
    Ok(())
}