# HTTP Signature Normalization Actix
_An HTTP Signatures library that leaves the signing to you_

- [crates.io](https://crates.io/crates/http-signature-normalization-actix)
- [docs.rs](https://docs.rs/http-signature-normalization-actix)
- [Hit me up on Mastodon](https://asonix.dog/@asonix)

Http Signature Normalization is a minimal-dependency crate for producing HTTP Signatures with user-provided signing and verification. The API is simple; there's a series of steps for creation and verification with types that ensure reasonable usage.

## Usage

This crate provides extensions the ClientRequest type from Actix Web, and provides middlewares for verifying HTTP Signatures, and optionally, Digest headers

#### First, add this crate to your dependencies
```toml
actix-rt = "2.6.0"
actix-web = "4.0.0"
thiserror = "0.1"
http-signature-normalization-actix = { version = "0.8.0", default-features = false, features = ["sha-2"] }
sha2 = "0.9"
```

#### Then, use it in your client

```rust
async fn request(config: Config) -> Result<(), Box<dyn std::error::Error>> {
    let digest = Sha256::new();

    let mut response = Client::default()
        .post("http://127.0.0.1:8010/")
        .append_header(("User-Agent", "Actix Web"))
        .append_header(("Accept", "text/plain"))
        .insert_header(actix_web::http::header::Date(SystemTime::now().into()))
        .signature_with_digest(config, "my-key-id", digest, "Hewwo-owo", |s| {
            info!("Signing String\n{}", s);
            Ok(base64::encode(s)) as Result<_, MyError>
        })
        .await?
        .send()
        .await
        .map_err(|e| {
            error!("Error, {}", e);
            MyError::SendRequest
        })?;

    let body = response.body().await.map_err(|e| {
        error!("Error, {}", e);
        MyError::Body
    })?;

    info!("{:?}", body);
    Ok(())
}
```

#### Or, use it in your server

```rust
#[derive(Clone, Debug)]
struct MyVerify;

impl SignatureVerify for MyVerify {
    type Error = MyError;
    type Future = Ready<Result<bool, Self::Error>>;

    fn signature_verify(
        &mut self,
        algorithm: Option<Algorithm>,
        key_id: String,
        signature: String,
        signing_string: String,
    ) -> Self::Future {
        match algorithm {
            Some(Algorithm::Hs2019) => (),
            _ => return ready(Err(MyError::Algorithm)),
        };

        if key_id != "my-key-id" {
            return ready(Err(MyError::Key));
        }

        let decoded = match base64::decode(&signature) {
            Ok(decoded) => decoded,
            Err(_) => return ready(Err(MyError::Decode)),
        };

        info!("Signing String\n{}", signing_string);

        ready(Ok(decoded == signing_string.as_bytes()))
    }
}

async fn index(
    _: DigestVerified,
    sig_verified: SignatureVerified,
    req: HttpRequest,
    _body: web::Bytes,
) -> &'static str {
    info!("Verified request for {}", sig_verified.key_id());
    info!("{:?}", req);
    "Eyyyyup"
}

#[actix_rt::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let env_filter = EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new("info"));

    let subscriber = tracing_subscriber::Registry::default()
        .with(env_filter)
        .with(ErrorLayer::default())
        .with(tracing_subscriber::fmt::layer());

    tracing::subscriber::set_global_default(subscriber)?;

    let config = Config::default().require_header("accept").require_digest();

    HttpServer::new(move || {
        App::new()
            .wrap(VerifyDigest::new(Sha256::new()).optional())
            .wrap(VerifySignature::new(MyVerify, config.clone()))
            .wrap(TracingLogger::default())
            .route("/", web::post().to(index))
    })
    .bind("127.0.0.1:8010")?
    .run()
    .await?;

    Ok(())
}

#[derive(Debug, thiserror::Error)]
enum MyError {
    #[error("Failed to verify, {0}")]
    Verify(#[from] PrepareVerifyError),

    #[error("Unsupported algorithm")]
    Algorithm,

    #[error("Couldn't decode signature")]
    Decode,

    #[error("Invalid key")]
    Key,
}

impl ResponseError for MyError {
    fn status_code(&self) -> StatusCode {
        StatusCode::BAD_REQUEST
    }

    fn error_response(&self) -> HttpResponse {
        HttpResponse::BadRequest().finish()
    }
}
```

### Contributing
Feel free to open issues for anything you find an issue with. Please note that any contributed code will be licensed under the AGPLv3.

### License
Copyright © 2022 Riley Trautman

HTTP Signature Normalization Actix is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

HTTP Signature Normalization Actix is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. This file is part of HTTP Signature Normalization Actix.

You should have received a copy of the GNU General Public License along with HTTP Signature Normalization Actix. If not, see [http://www.gnu.org/licenses/](http://www.gnu.org/licenses/).