Async reqwest - set User Agent

cargo add reqwest -F json
cargo add tokio -F full

Cargo.toml

[package]
name = "async-reqwest-set-user-agent"
version = "0.1.0"
edition = "2024"

[dependencies]
reqwest = { version = "0.12.23", features = ["json"] }
tokio = { version = "1.47.1", features = ["full"] }

The code

use std::collections::HashMap;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let url = get_url("headers");

    let resp = reqwest::get(url)
        .await?
        .json::<HashMap<String, String>>()
        .await?;
    println!("{:#?}", resp);
    Ok(())
}

fn get_url(path: &str) -> String {
    let host = std::env::args().nth(1).unwrap_or("httpbin.org".into());
    let url = if host == "localhost" {
        format!("http://localhost/{path}")
    } else {
        format!("https://{host}/{path}")
    };

    url
}