Rocket - Hello World returning HTML

Part of the series about the Rocket web framework.

Dependencies

examples/rocket/hello-world-html/Cargo.toml

[package]
name = "hello-world-html"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
rocket = "0.5.0"

Code

examples/rocket/hello-world-html/src/main.rs

#[macro_use]
extern crate rocket;

use rocket::response::content;

#[get("/")]
fn index() -> content::RawHtml<&'static str> {
    content::RawHtml("Hello, <b>world!</b>")
}

#[launch]
fn rocket() -> _ {
    rocket::build().mount("/", routes![index])
}

#[cfg(test)]
mod tests;

The key is that the route function is defined to return content::RawHtml<&'static str> and then we call content::RawHtml to return the HTML.

This will set the Content-type to text/html.

Testing

We can verify it in our test using the response.headers().get_one("Content-Type") call and running

cargo test

examples/rocket/hello-world-html/src/tests.rs

use rocket::http::Status;
use rocket::local::blocking::Client;

#[test]
fn hello_world() {
    let client = Client::tracked(super::rocket()).unwrap();
    let response = client.get("/").dispatch();

    assert_eq!(response.status(), Status::Ok);
    assert_eq!(
        response.headers().get_one("Content-Type").unwrap(),
        "text/html; charset=utf-8"
    );
    assert_eq!(response.into_string(), Some("Hello, <b>world!</b>".into()));
}

Running

We can also launch the web service using

cargo run

And verify the output in our browser or by using curl in a separate terminal:

$ curl -i http://localhost:8000

HTTP/1.1 200 OK
content-type: text/html; charset=utf-8
server: Rocket
permissions-policy: interest-cohort=()
x-content-type-options: nosniff
x-frame-options: SAMEORIGIN
content-length: 20
date: Tue, 02 Jan 2024 14:11:04 GMT

Hello, <b>world!</b>