How to retrieve HTTP headers from a request in Rocket? - rust

Question

I would do something like this using flask in Python:
#app.route('/login/', methods=['POST'])
def login():
token = request.headers["token"]
I cannot figure out how to access the token header and store it as a String variable.
#![feature(proc_macro_hygiene, decl_macro)]
use rocket::{
config::{Config, Environment},
*,
};
fn main() {
let config = Config::build(Environment::Production)
.address("0.0.0.0")
.port(PORT)
.finalize()
.unwrap();
rocket::ignite().mount("/", routes![login]).launch();
}
#[post("/login")]
fn login() {
// Retrieve headers from request.
}

Answer 1

Ibraheem Ahmed's answer was useful, but I could not figure out how to use Infallible. I solved the issue by doing:
struct Token(String);
#[derive(Debug)]
enum ApiTokenError {
Missing,
Invalid,
}
impl<'a, 'r> FromRequest<'a, 'r> for Token {
type Error = ApiTokenError;
fn from_request(request: &'a Request<'r>) -> request::Outcome<Self, Self::Error> {
let token = request.headers().get_one("token");
match token {
Some(token) => {
// check validity
Outcome::Success(Token(token.to_string()))
}
None => Outcome::Failure((Status::Unauthorized, ApiTokenError::Missing)),
}
}
}

Answer 2

Rocket handlers are based on Request Guards. You do not directly access the request in your handler. Instead, you create a type that implements FromRequest.
You can create a token struct that holds a string:
struct Token(String);
And implement FromRequest for the token:
impl<'a, 'r> FromRequest<'a, 'r> for Token {
type Error = Infallible;
fn from_request(request: &'a Request<'r>) -> request::Outcome<Self, Self::Error> {
let token = request.headers().get_one("token");
match token {
Some(token) => {
// check validity
Outcome::Success(Token(token.to_string()))
},
// token does not exist
None => Outcome::Failure(Status::Unauthorized)
}
}
}
Now you can use that Token as a request guard:
#[post("/login")]
fn login(token: Token) {
}
If the from_request method for Token fails, a Status::Unauthorized will be returned. Otherwise, your handler will be called, and you can handle the authentication logic.