Rocket - Use state within my guards fails as traits are not implemented - rust

Question

I want to use state within my guards. I want to have routes that required authentication with an api key which I want to define in my Rocket.toml. But running this code I get the following error:
the trait From<(Status, ())> is not implemented for (Status, ApiKeyError)
for this line of code let config_state = try_outcome!(req.guard::<State<'_, Config>>().await);
How do I implement this trait? Or is there even a better solution to manage the api token in Rocket.
I am using the 0.5.0-devversion of Rocket.
#[macro_use] extern crate rocket;
use rocket::http::Status;
use rocket::request::{Outcome, Request, FromRequest};
use rocket::State;
use rocket::fairing::AdHoc;
use serde::Deserialize;
#[derive(Deserialize)]
struct Config {
api_key: String,
}
struct ApiKey<'r>(&'r str);
#[derive(Debug)]
enum ApiKeyError {
Missing,
Invalid,
}
#[rocket::async_trait]
impl<'r> FromRequest<'r> for ApiKey<'r> {
type Error = ApiKeyError;
async fn from_request(req: &'r Request<'_>) -> Outcome<Self, Self::Error> {
let config_state = try_outcome!(req.guard::<State<'_, Config>>().await);
/// Returns true if `key` is a valid API key string.
fn is_valid(key: &str, api_key: String) -> bool {
key == api_key
}
match req.headers().get_one("Authorization") {
None => Outcome::Failure((Status::Unauthorized, ApiKeyError::Missing)),
Some(key) if is_valid(key, config_state.api_key) => Outcome::Success(ApiKey(key)),
Some(_) => Outcome::Failure((Status::Unauthorized, ApiKeyError::Invalid)),
}
}
}
#[get("/")]
async fn index(config: State<'_, Config>, key: ApiKey<'_>) -> &'static str {
"Hello, world!"
}
fn rocket() -> rocket::Rocket {
let rocket = rocket::ignite();
let figment = rocket.figment();
let config: Config = figment.extract().expect("config");
rocket
.mount("/", routes![index])
.attach(AdHoc::config::<Config>())
}
#[rocket::main]
async fn main() {
rocket()
.launch()
.await;
}

Answer 1

I already stored the config with AdHoch::config() but to retrieve it within the guard I need to use request.rocket().state::<Config>(). The corrected source code is below:
#[macro_use] extern crate rocket;
use rocket::http::Status;
use rocket::request::{Outcome, Request, FromRequest};
use rocket::State;
use rocket::fairing::AdHoc;
use serde::Deserialize;
#[derive(Deserialize)]
struct Config {
api_key: String,
}
struct ApiKey<'r>(&'r str);
#[derive(Debug)]
enum ApiKeyError {
Missing,
Invalid,
}
#[rocket::async_trait]
impl<'r> FromRequest<'r> for ApiKey<'r> {
type Error = ApiKeyError;
async fn from_request(req: &'r Request<'_>) -> Outcome<Self, Self::Error> {
// Retrieve the config state like this
let config = req.rocket().state::<Config>().unwrap();
/// Returns true if `key` is a valid API key string.
fn is_valid(key: &str, api_key: &str) -> bool {
key == api_key
}
match req.headers().get_one("Authorization") {
None => Outcome::Failure((Status::Unauthorized, ApiKeyError::Missing)),
Some(key) if is_valid(key, &config.api_key) => Outcome::Success(ApiKey(key)),
Some(_) => Outcome::Failure((Status::Unauthorized, ApiKeyError::Invalid)),
}
}
}
#[get("/")]
async fn index(config: State<'_, Config>, key: ApiKey<'_>) -> &'static str {
"Hello, world!"
}
fn rocket() -> rocket::Rocket {
let rocket = rocket::ignite();
let figment = rocket.figment();
let config: Config = figment.extract().expect("config");
rocket
.mount("/", routes![index])
.attach(AdHoc::config::<Config>())
}
#[rocket::main]
async fn main() {
rocket()
.launch()
.await;
}