feat(client): add default header middleware

client/src/middleware/default_headers.rs

@@ -0,0 +1,111 @@
+use std::ops::{Deref, DerefMut};
+
+use crate::{
+    http::HeaderMap,
+    service::{Service, ServiceRequest},
+};
+
+/// A default header map that can be used to append, replace or set headers if they are unset.
+pub enum DefaultHeaderMap {
+    Append(HeaderMap),
+    Replace(HeaderMap),
+    SetIfUnset(HeaderMap),
+}
+
+impl DefaultHeaderMap {
+    pub fn new_append() -> Self {
+        Self::Append(HeaderMap::new())
+    }
+
+    pub fn new_replace() -> Self {
+        Self::Replace(HeaderMap::new())
+    }
+
+    pub fn new_set_if_unset() -> Self {
+        Self::SetIfUnset(HeaderMap::new())
+    }
+}
+
+impl Deref for DefaultHeaderMap {
+    type Target = HeaderMap;
+
+    fn deref(&self) -> &Self::Target {
+        match self {
+            Self::Append(headers) => headers,
+            Self::Replace(headers) => headers,
+            Self::SetIfUnset(headers) => headers,
+        }
+    }
+}
+
+impl DerefMut for DefaultHeaderMap {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        match self {
+            Self::Append(headers) => headers,
+            Self::Replace(headers) => headers,
+            Self::SetIfUnset(headers) => headers,
+        }
+    }
+}
+
+pub struct DefaultHeaders<S> {
+    service: S,
+    default_header_map: DefaultHeaderMap,
+}
+
+impl<S> DefaultHeaders<S> {
+    pub fn new(service: S, default_header_map: DefaultHeaderMap) -> Self {
+        Self {
+            service,
+            default_header_map,
+        }
+    }
+}
+
+impl<'r, 'c, S, Res, Err> Service<ServiceRequest<'r, 'c>> for DefaultHeaders<S>
+where
+    S: for<'r2, 'c2> Service<ServiceRequest<'r2, 'c2>, Response = Res, Error = Err> + Send + Sync,
+{
+    type Response = Res;
+    type Error = Err;
+
+    async fn call(&self, req: ServiceRequest<'r, 'c>) -> Result<Self::Response, Self::Error> {
+        match &self.default_header_map {
+            DefaultHeaderMap::Append(headers) => {
+                for (key, value) in headers {
+                    req.req.headers_mut().append(key, value.clone());
+                }
+            }
+            DefaultHeaderMap::Replace(headers) => {
+                for (key, value) in headers {
+                    req.req.headers_mut().insert(key, value.clone());
+                }
+            }
+            DefaultHeaderMap::SetIfUnset(headers) => {
+                for (key, value) in headers {
+                    req.req.headers_mut().entry(key).or_insert(value.clone());
+                }
+            }
+        }
+
+        self.service.call(req).await
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::Client;
+    use xitca_http::http::HeaderValue;
+
+    use super::*;
+
+    #[tokio::test]
+    async fn build_default_headers_mw() {
+        let mut default_headers = DefaultHeaderMap::new_append();
+        default_headers.insert("content-type", HeaderValue::from_static("application/json"));
+
+        let _ = Client::builder()
+            .middleware(move |x| DefaultHeaders::new(x, default_headers))
+            .finish();
+    }
+}

client/src/middleware/mod.rs

@@ -1,5 +1,6 @@
 //! middleware offer extended functionality to http client.
 
+mod default_headers;
 mod redirect;
 
 #[cfg(feature = "compress")]
@@ -8,4 +9,5 @@ mod decompress;
 #[cfg(feature = "compress")]
 pub use decompress::Decompress;
 
+pub use default_headers::{DefaultHeaderMap, DefaultHeaders};
 pub use redirect::FollowRedirect;