implementing working demonstration of calling Fetch asynchronously

components/net_traits/response.rs

@@ -4,10 +4,10 @@
 
 //! The [Response](https://fetch.spec.whatwg.org/#responses) object
 //! resulting from a [fetch operation](https://fetch.spec.whatwg.org/#concept-fetch)
-use hyper::header::Headers;
+use hyper::header::{AccessControlExposeHeaders, Headers};
 use hyper::status::StatusCode;
-use std::cell::RefCell;
-use std::rc::Rc;
+use std::ascii::AsciiExt;
+use std::cell::{Cell, RefCell};
 use url::Url;
 
 /// [Response type](https://fetch.spec.whatwg.org/#concept-response-type)
@@ -38,6 +38,16 @@ pub enum ResponseBody {
     Done(Vec<u8>),
 }
 
+impl ResponseBody {
+    pub fn is_done(&self) -> bool {
+        match *self {
+            ResponseBody::Done(..) => true,
+            ResponseBody::Empty | ResponseBody::Receiving(..) => false
+        }
+    }
+}
+
+
 /// [Cache state](https://fetch.spec.whatwg.org/#concept-response-cache-state)
 #[derive(Clone, Debug)]
 pub enum CacheState {
@@ -76,7 +86,9 @@ pub struct Response {
     pub https_state: HttpsState,
     /// [Internal response](https://fetch.spec.whatwg.org/#concept-internal-response), only used if the Response
     /// is a filtered response
-    pub internal_response: Option<Rc<Response>>,
+    pub internal_response: Option<Box<Response>>,
+    /// whether or not to try to return the internal_response when asked for actual_response
+    pub return_internal: Cell<bool>,
 }
 
 impl Response {
@@ -91,7 +103,8 @@ impl Response {
             body: RefCell::new(ResponseBody::Empty),
             cache_state: CacheState::None,
             https_state: HttpsState::None,
-            internal_response: None
+            internal_response: None,
+            return_internal: Cell::new(true)
         }
     }
 
@@ -101,4 +114,92 @@ impl Response {
             _ => false
         }
     }
+
+    pub fn get_actual_response(&self) -> &Response {
+        if self.return_internal.get() && self.internal_response.is_some() {
+            &**self.internal_response.as_ref().unwrap()
+        } else {
+            self
+        }
+    }
+
+    pub fn to_actual(self) -> Response {
+        if self.return_internal.get() && self.internal_response.is_some() {
+            *self.internal_response.unwrap()
+        } else {
+            self
+        }
+    }
+
+    /// Convert to a filtered response, of type `filter_type`.
+    /// Do not use with type Error or Default
+    pub fn to_filtered(self, filter_type: ResponseType) -> Response {
+
+        assert!(filter_type != ResponseType::Error);
+        assert!(filter_type != ResponseType::Default);
+
+        let old_response = self.to_actual();
+
+        if Response::is_network_error(&old_response) {
+            return Response::network_error();
+        }
+
+        let old_headers = old_response.headers.clone();
+        let mut response = old_response.clone();
+        response.internal_response = Some(Box::new(old_response));
+        response.response_type = filter_type;
+
+        match filter_type {
+
+            ResponseType::Default | ResponseType::Error => unreachable!(),
+
+            ResponseType::Basic => {
+                let headers = old_headers.iter().filter(|header| {
+                    match &*header.name().to_ascii_lowercase() {
+                        "set-cookie" | "set-cookie2" => false,
+                        _ => true
+                    }
+                }).collect();
+                response.headers = headers;
+            },
+
+            ResponseType::CORS => {
+
+                let access = old_headers.get::<AccessControlExposeHeaders>();
+                let allowed_headers = access.as_ref().map(|v| &v[..]).unwrap_or(&[]);
+
+                let headers = old_headers.iter().filter(|header| {
+                    match &*header.name().to_ascii_lowercase() {
+                        "cache-control" | "content-language" | "content-type" |
+                        "expires" | "last-modified" | "pragma" => true,
+                        "set-cookie" | "set-cookie2" => false,
+                        header => {
+                            let result =
+                                allowed_headers.iter().find(|h| *header == *h.to_ascii_lowercase());
+                            result.is_some()
+                        }
+                    }
+                }).collect();
+                response.headers = headers;
+            },
+
+            ResponseType::Opaque => {
+                response.url_list = RefCell::new(vec![]);
+                response.url = None;
+                response.headers = Headers::new();
+                response.status = None;
+                response.body = RefCell::new(ResponseBody::Empty);
+                response.cache_state = CacheState::None;
+            },
+
+            ResponseType::OpaqueRedirect => {
+                response.headers = Headers::new();
+                response.status = None;
+                response.body = RefCell::new(ResponseBody::Empty);
+                response.cache_state = CacheState::None;
+            }
+        }
+
+        response
+    }
 }