Merge pull request #42 from tzilist/feat-default-headers

Feature: Default Headers Middleware

examples/default_headers.rs

@@ -0,0 +1,16 @@
+#![feature(async_await)]
+
+use tide::middleware::DefaultHeaders;
+
+fn main() {
+    let mut app = tide::App::new(());
+
+    app.middleware(
+        DefaultHeaders::new()
+            .header("X-Version", "1.0.0")
+            .header("X-Servier", "Tide"),
+    );
+
+    app.at("/").get(async || "Hello, world!");
+    app.serve("127.0.0.1:7878")
+}

src/lib.rs

@@ -17,7 +17,7 @@ pub mod body;
 mod endpoint;
 mod extract;
 pub mod head;
-mod middleware;
+pub mod middleware;
 mod request;
 mod response;
 mod router;

src/middleware/default_headers.rs

@@ -0,0 +1,49 @@
+use futures::future::FutureObj;
+
+use http::{
+    header::{HeaderValue, IntoHeaderName},
+    HeaderMap, HttpTryFrom,
+};
+
+use crate::{head::Head, Middleware, Response};
+
+#[derive(Clone, Default)]
+pub struct DefaultHeaders {
+    headers: HeaderMap,
+}
+
+impl DefaultHeaders {
+    pub fn new() -> DefaultHeaders {
+        DefaultHeaders::default()
+    }
+
+    #[inline]
+    pub fn header<K, V>(mut self, key: K, value: V) -> Self
+    where
+        K: IntoHeaderName,
+        HeaderValue: HttpTryFrom<V>,
+    {
+        let value = HeaderValue::try_from(value)
+            .map_err(Into::into)
+            .expect("Cannot create default header");
+
+        self.headers.append(key, value);
+
+        self
+    }
+}
+
+impl<Data> Middleware<Data> for DefaultHeaders {
+    fn response(
+        &self,
+        data: &mut Data,
+        head: &Head,
+        mut resp: Response,
+    ) -> FutureObj<'static, Response> {
+        let headers = resp.headers_mut();
+        for (key, value) in self.headers.iter() {
+            headers.entry(key).unwrap().or_insert_with(|| value.clone());
+        }
+        FutureObj::new(Box::new(async { resp }))
+    }
+}

src/middleware.rs → src/middleware/mod.rs

@@ -2,6 +2,10 @@ use futures::future::FutureObj;
 
 use crate::{head::Head, Request, Response, RouteMatch};
 
+mod default_headers;
+
+pub use self::default_headers::DefaultHeaders;
+
 /// Middleware for an app with state of type `Data`
 pub trait Middleware<Data>: Send + Sync {
     /// Asynchronously transform the incoming request, or abort further handling by immediately
@@ -11,15 +15,19 @@ pub trait Middleware<Data>: Send + Sync {
         data: &mut Data,
         req: Request,
         params: &RouteMatch<'_>,
-    ) -> FutureObj<'static, Result<Request, Response>>;
+    ) -> FutureObj<'static, Result<Request, Response>> {
+        FutureObj::new(Box::new(async { Ok(req) }))
+    }
 
     /// Asynchronously transform the outgoing response.
     fn response(
         &self,
         data: &mut Data,
         head: &Head,
         resp: Response,
-    ) -> FutureObj<'static, Response>;
+    ) -> FutureObj<'static, Response> {
+        FutureObj::new(Box::new(async { resp }))
+    }
 
     // TODO: provide the following, intended to fire *after* the body has been fully sent