How do I set the request headers using Reqwest? - http

Question

I need to make a GET request to a website with a cookie using the Reqwest library. I figured out how to send a GET request:
let response = reqwest::get("http://example.com")?;
How do I send the same request but adding some custom headers?

Answer 1

Reqwest 0.10
Starting at the crate's documentation, we see:
For a single request, you can use the get shortcut method.
get's documentation states:
This function creates a new internal Client on each call, and so should not be used if making many requests. Create a Client instead.
Client has a request method which states:
Returns a RequestBuilder, which will allow setting headers and request body before sending.
RequestBuilder has a header method. This can be used as:
use reqwest::header::USER_AGENT;
let client = reqwest::Client::new();
let res = client
.get("https://www.rust-lang.org")
.header(USER_AGENT, "My Rust Program 1.0")
.send()
.await?;
How do I add custom headers?
If you look at the signature for header, you will see that it accepts generic types:
pub fn header<K, V>(self, key: K, value: V) -> RequestBuilder where
HeaderName: TryFrom<K>,
<HeaderName as TryFrom<K>>::Error: Into<Error>,
HeaderValue: TryFrom<V>,
<HeaderValue as TryFrom<V>>::Error: Into<Error>,
There is an implementation of TryFrom<&'a str> for HeaderName, so you can use a string literal:
use reqwest; // 0.10.0
use tokio; // 0.2.6
#[tokio::main]
async fn main() -> Result<(), reqwest::Error> {
let client = reqwest::Client::new();
let res = client
.get("https://www.rust-lang.org")
.header("X-My-Custom-Header", "foo")
.send()
.await?;
Ok(())
}

Answer 2

Send Cookie in reqwest client with version ~0.9.19
use reqwest; // 0.9.19
use http::{HeaderMap, HeaderValue, header::{COOKIE}};
// create client first
let init_client = reqwest::Client::builder()
.cookie_store(true).build().unwrap();
// create Header Map
// Here cookie store is optional based on if making more than one request with the // same client
let mut headers = HeaderMap::new();
headers.insert(COOKIE, HeaderValue::from_str("key=value").unwrap());
let resp = init_client.get("api")
.headers(headers)
.query(&[("name", "foo")])
.send()
.map(|resp|{
println!("{:?}", resp.status());
resp
})
.map_err(|err|{
println!("{:?}", err);
err
});
Hope This may help.