volo-http 0.5.5

//! [`Layer`]s for inserting header to requests.
//!
//! - [`Header`] inserts any [`HeaderName`] and [`HeaderValue`]
//! - [`Host`] inserts the given `Host` or a `Host` generated by the target hostname or target
//!   address with its scheme and port.
//! - [`UserAgent`] inserts the given `User-Agent` or a `User-Agent` generated by the current
//!   package information.

use std::{error::Error, future::Future};

use http::header::{self, HeaderName, HeaderValue};
use motore::{layer::Layer, service::Service};

use crate::{
    client::{Target, target::RemoteHost, utils::is_default_port},
    context::ClientContext,
    error::client::{Result, builder_error},
    request::Request,
};

/// [`Layer`] for inserting a header to requests.
#[derive(Clone, Debug)]
pub struct Header {
    key: HeaderName,
    val: HeaderValue,
}

impl Header {
    /// Create a new [`Header`] layer for inserting a header to requests.
    ///
    /// This function takes [`HeaderName`] and [`HeaderValue`], users should create it by
    /// themselves.
    ///
    /// For using string types directly, see [`Header::try_new`].
    pub fn new(key: HeaderName, val: HeaderValue) -> Self {
        Self { key, val }
    }

    /// Create a new [`Header`] layer for inserting a header to requests.
    ///
    /// This function takes any types that can be converted into [`HeaderName`] or [`HeaderValue`].
    /// If the values are invalid [`HeaderName`] or [`HeaderValue`], an [`ClientError`] with
    /// [`ErrorKind::Builder`] will be returned.
    ///
    /// [`ClientError`]: crate::error::client::ClientError
    /// [`ErrorKind::Builder`]: crate::error::client::ErrorKind::Builder
    pub fn try_new<K, V>(key: K, val: V) -> Result<Self>
    where
        K: TryInto<HeaderName>,
        K::Error: Error + Send + Sync + 'static,
        V: TryInto<HeaderValue>,
        V::Error: Error + Send + Sync + 'static,
    {
        let key = key.try_into().map_err(builder_error)?;
        let val = val.try_into().map_err(builder_error)?;

        Ok(Self::new(key, val))
    }
}

impl<S> Layer<S> for Header {
    type Service = HeaderService<S>;

    fn layer(self, inner: S) -> Self::Service {
        HeaderService {
            inner,
            key: self.key,
            val: self.val,
        }
    }
}

/// [`Service`] generated by [`Header`].
///
/// See [`Header`], [`Header::new`] and [`Header::try_new`] for more details.
pub struct HeaderService<S> {
    inner: S,
    key: HeaderName,
    val: HeaderValue,
}

impl<Cx, B, S> Service<Cx, Request<B>> for HeaderService<S>
where
    S: Service<Cx, Request<B>>,
{
    type Response = S::Response;
    type Error = S::Error;

    fn call(
        &self,
        cx: &mut Cx,
        mut req: Request<B>,
    ) -> impl Future<Output = Result<Self::Response, Self::Error>> + Send {
        req.headers_mut().insert(self.key.clone(), self.val.clone());
        self.inner.call(cx, req)
    }
}

/// [`Layer`] for inserting `Host` into the request header.
#[derive(Clone, Debug, Default)]
pub enum Host {
    /// Do not insert `Host` into the request headers.
    None,
    /// If there is no `Host` in request headers, the layer will generate it through target
    /// address.
    #[default]
    Auto,
    /// Forcely use the given value as `Host` in request headers, it will override the previous
    /// one.
    Force(HeaderValue),
    /// If there is no `Host` in request headers, the `Host` will be set to the given value.
    Fallback(HeaderValue),
}

impl<S> Layer<S> for Host {
    type Service = HostService<S>;

    fn layer(self, inner: S) -> Self::Service {
        HostService {
            inner,
            config: self,
        }
    }
}

/// [`Service`] generated by [`Host`].
///
/// See [`Host`] for more details.
pub struct HostService<S> {
    inner: S,
    config: Host,
}

#[cfg(target_family = "unix")]
const UDS_HOST: HeaderValue = HeaderValue::from_static("unix-domain-socket");

pub(super) fn gen_host(target: &Target) -> Option<HeaderValue> {
    let rt = match target {
        Target::None => return None,
        Target::Remote(rt) => rt,
        #[cfg(target_family = "unix")]
        Target::Local(_) => return Some(UDS_HOST.clone()),
    };
    let default_port = is_default_port(&rt.scheme, rt.port);
    match &rt.host {
        RemoteHost::Ip(ip) => {
            let s = if default_port {
                if ip.is_ipv4() {
                    format!("{ip}")
                } else {
                    format!("[{ip}]")
                }
            } else {
                let port = rt.port;
                if ip.is_ipv4() {
                    format!("{ip}:{port}")
                } else {
                    format!("[{ip}]:{port}")
                }
            };
            HeaderValue::from_str(&s).ok()
        }
        RemoteHost::Name(name) => {
            let port = rt.port;
            if default_port {
                HeaderValue::from_str(name).ok()
            } else {
                HeaderValue::from_str(&format!("{name}:{port}")).ok()
            }
        }
    }
}

impl<B, S> Service<ClientContext, Request<B>> for HostService<S>
where
    S: Service<ClientContext, Request<B>>,
{
    type Response = S::Response;
    type Error = S::Error;

    fn call(
        &self,
        cx: &mut ClientContext,
        mut req: Request<B>,
    ) -> impl Future<Output = Result<Self::Response, Self::Error>> + Send {
        match &self.config {
            Host::None => {}
            Host::Auto => {
                if !req.headers().contains_key(header::HOST) {
                    if let Some(val) = gen_host(cx.target()) {
                        req.headers_mut().insert(header::HOST, val);
                    }
                }
            }
            Host::Force(val) => {
                req.headers_mut().insert(header::HOST, val.clone());
            }
            Host::Fallback(val) => {
                if !req.headers().contains_key(header::HOST) {
                    req.headers_mut().insert(header::HOST, val.clone());
                }
            }
        }

        self.inner.call(cx, req)
    }
}

const PKG_NAME_WITH_VER: &str = concat!(env!("CARGO_PKG_NAME"), '/', env!("CARGO_PKG_VERSION"));

/// [`Layer`] for inserting `User-Agent` into the request header.
///
/// See [`UserAgent::new`] for more details.
pub struct UserAgent {
    val: HeaderValue,
}

impl UserAgent {
    /// Create a new [`UserAgent`] layer that inserts `User-Agent` into the request header.
    ///
    /// Note that the layer only inserts it if there is no `User-Agent`
    pub fn new(val: HeaderValue) -> Self {
        Self { val }
    }

    /// Create a new [`UserAgent`] layer with the package name and package version as its default
    /// value.
    ///
    /// Note that the layer only inserts it if there is no `User-Agent`
    pub fn auto() -> Self {
        Self {
            val: HeaderValue::from_static(PKG_NAME_WITH_VER),
        }
    }
}

impl<S> Layer<S> for UserAgent {
    type Service = UserAgentService<S>;

    fn layer(self, inner: S) -> Self::Service {
        UserAgentService {
            inner,
            val: self.val,
        }
    }
}

/// [`Service`] generated by [`UserAgent`].
///
/// See [`UserAgent`] and [`UserAgent::new`] for more details.
pub struct UserAgentService<S> {
    inner: S,
    val: HeaderValue,
}

impl<Cx, B, S> Service<Cx, Request<B>> for UserAgentService<S>
where
    S: Service<Cx, Request<B>>,
{
    type Response = S::Response;
    type Error = S::Error;

    fn call(
        &self,
        cx: &mut Cx,
        mut req: Request<B>,
    ) -> impl Future<Output = Result<Self::Response, Self::Error>> + Send {
        if !req.headers().contains_key(header::USER_AGENT) {
            req.headers_mut()
                .insert(header::USER_AGENT, self.val.clone());
        }
        self.inner.call(cx, req)
    }
}

#[cfg(test)]
mod layer_header_tests {
    use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};

    use faststr::FastStr;
    use http::uri::Scheme;

    use crate::client::{
        Target,
        layer::header::gen_host,
        target::{RemoteHost, RemoteTarget},
    };

    const IPV4: IpAddr = IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1));
    const IPV6: IpAddr = IpAddr::V6(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1));

    const fn host_target(scheme: Scheme, host: &'static str, port: u16) -> Target {
        Target::Remote(RemoteTarget {
            scheme,
            host: RemoteHost::Name(FastStr::from_static_str(host)),
            port,
        })
    }

    const fn ip_target(scheme: Scheme, ip: IpAddr, port: u16) -> Target {
        Target::Remote(RemoteTarget {
            scheme,
            host: RemoteHost::Ip(ip),
            port,
        })
    }

    #[test]
    fn gen_host_test() {
        // no host, no addr
        assert_eq!(gen_host(&Target::None), None);

        // host with default port
        assert_eq!(
            gen_host(&host_target(Scheme::HTTP, "github.com", 80)).unwrap(),
            "github.com",
        );
        // host with non-default port
        assert_eq!(
            gen_host(&host_target(Scheme::HTTP, "github.com", 8000)).unwrap(),
            "github.com:8000",
        );
        assert_eq!(
            gen_host(&host_target(Scheme::HTTP, "github.com", 443)).unwrap(),
            "github.com:443",
        );

        // ipv4 addr with default port
        assert_eq!(
            gen_host(&ip_target(Scheme::HTTP, IPV4, 80)).unwrap(),
            "127.0.0.1",
        );
        // ipv4 addr with non-default port
        assert_eq!(
            gen_host(&ip_target(Scheme::HTTP, IPV4, 8000)).unwrap(),
            "127.0.0.1:8000",
        );
        assert_eq!(
            gen_host(&ip_target(Scheme::HTTP, IPV4, 443)).unwrap(),
            "127.0.0.1:443",
        );

        // ipv6 addr with default port
        assert_eq!(
            gen_host(&ip_target(Scheme::HTTP, IPV6, 80)).unwrap(),
            "[::1]",
        );
        // ipv6 addr with non-default port
        assert_eq!(
            gen_host(&ip_target(Scheme::HTTP, IPV6, 8000)).unwrap(),
            "[::1]:8000",
        );
        assert_eq!(
            gen_host(&ip_target(Scheme::HTTP, IPV6, 443)).unwrap(),
            "[::1]:443",
        );
    }

    #[cfg(feature = "__tls")]
    #[test]
    fn gen_host_with_tls_test() {
        // host with default port
        assert_eq!(
            gen_host(&host_target(Scheme::HTTPS, "github.com", 443)).unwrap(),
            "github.com",
        );
        // host with non-default port
        assert_eq!(
            gen_host(&host_target(Scheme::HTTPS, "github.com", 4430)).unwrap(),
            "github.com:4430"
        );
        assert_eq!(
            gen_host(&host_target(Scheme::HTTPS, "github.com", 80)).unwrap(),
            "github.com:80"
        );

        // ipv4 addr with default port
        assert_eq!(
            gen_host(&ip_target(Scheme::HTTPS, IPV4, 443)).unwrap(),
            "127.0.0.1"
        );
        // ipv4 addr with non-default port
        assert_eq!(
            gen_host(&ip_target(Scheme::HTTPS, IPV4, 4430)).unwrap(),
            "127.0.0.1:4430"
        );
        assert_eq!(
            gen_host(&ip_target(Scheme::HTTPS, IPV4, 80)).unwrap(),
            "127.0.0.1:80"
        );

        // ipv6 addr with default port
        assert_eq!(
            gen_host(&ip_target(Scheme::HTTPS, IPV6, 443)).unwrap(),
            "[::1]"
        );
        // ipv6 addr with non-default port
        assert_eq!(
            gen_host(&ip_target(Scheme::HTTPS, IPV6, 4430)).unwrap(),
            "[::1]:4430"
        );
        assert_eq!(
            gen_host(&ip_target(Scheme::HTTPS, IPV6, 80)).unwrap(),
            "[::1]:80"
        );
    }
}