make protocol handlers registrable (#33104)

Signed-off-by: webbeef <me@webbeef.org>

ports/servoshell/desktop/protocols/urlinfo.rs

@@ -0,0 +1,46 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use std::future::Future;
+use std::pin::Pin;
+
+use headers::{ContentType, HeaderMapExt};
+use http::StatusCode;
+use net::fetch::methods::{DoneChannel, FetchContext};
+use net::protocols::ProtocolHandler;
+use net_traits::request::Request;
+use net_traits::response::{Response, ResponseBody};
+use net_traits::ResourceFetchTiming;
+
+#[derive(Default)]
+pub struct UrlInfoProtocolHander {}
+
+// A simple protocol handler that displays information about the url itself.
+impl ProtocolHandler for UrlInfoProtocolHander {
+    fn load(
+        &self,
+        request: &mut Request,
+        _done_chan: &mut DoneChannel,
+        _context: &FetchContext,
+    ) -> Pin<Box<dyn Future<Output = Response> + Send>> {
+        let url = request.current_url();
+
+        let content = format!(
+            r#"Full url: {url}
+  scheme: {}
+    path: {}
+   query: {:?}"#,
+            url.scheme(),
+            url.path(),
+            url.query()
+        );
+        let mut response = Response::new(url, ResourceFetchTiming::new(request.timing_type()));
+        *response.body.lock().unwrap() = ResponseBody::Done(content.as_bytes().to_vec());
+        response.headers.typed_insert(ContentType::text());
+        response.status = Some((StatusCode::OK, "OK".to_string()));
+        response.raw_status = Some((StatusCode::OK.as_u16(), b"OK".to_vec()));
+
+        Box::pin(std::future::ready(response))
+    }
+}