Making Requests
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 String
using read_to_string
.
use error_chain::error_chain;
use std::io::Read;
error_chain! {
foreign_links {
Io(std::io::Error);
HttpRequest(reqwest::Error);
}
}
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.
Make sure to add tokio = {version = "1.21.2", features = ["full"]} to
your cargo.toml file.
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 error_chain::error_chain;
error_chain! {
foreign_links {
Io(std::io::Error);
HttpRequest(reqwest::Error);
}
}
#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
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
Builds complex URL with Url::parse_with_params
. Sets standard headers
header::USER_AGENT
, and custom X-Powered-By
header with
RequestBuilder::HeaderName::TryFrom<&'a str>
then makes the request with
RequestBuilder::send
.
The request target http://httpbin.org/headers responds with a JSON dict containing all request headers for easy verification.
use error_chain::error_chain;
use reqwest::Url;
use reqwest::blocking::Client;
use reqwest::header::USER_AGENT;
use serde::Deserialize;
use std::collections::HashMap;
error_chain! {
foreign_links {
Reqwest(reqwest::Error);
UrlParse(url::ParseError);
}
}
#[derive(Deserialize, Debug)]
pub struct HeadersEcho {
pub headers: HashMap<String, String>,
}
fn main() -> Result<()> {
let url = Url::parse_with_params(
"http://httpbin.org/headers",
&[("lang", "rust"), ("browser", "servo")],
)?;
let response = Client::new()
.get(url)
.header(USER_AGENT, "Rust-test-agent")
.header("X-Powered-By", "Rust")
.send()?;
assert_eq!(
response.url().as_str(),
"http://httpbin.org/headers?lang=rust&browser=servo"
);
let out: HeadersEcho = response.json()?;
assert_eq!(out.headers["User-Agent"], "Rust-test-agent");
assert_eq!(out.headers["X-Powered-By"], "Rust");
Ok(())
}