4 files changed, 84 insertions, 22 deletions

diff --git a/src/http.rs b/src/http.rs
index 86684207d..0d3189d27 100644
--- a/src/http.rs
+++ b/src/http.rs
@@ -4,12 +4,10 @@ use errors;
 use errors::{DenoError, DenoResult};
 use tokio_util;
 
-use futures;
-use futures::future::Either;
+use futures::future::{loop_fn, Loop};
 use futures::{Future, Stream};
 use hyper;
-use hyper::client::Client;
-use hyper::client::HttpConnector;
+use hyper::client::{Client, HttpConnector};
 use hyper::Uri;
 use hyper_rustls;
 
@@ -33,24 +31,46 @@ pub fn get_client() -> Client<Connector, hyper::Body> {
 pub fn fetch_sync_string(module_name: &str) -> DenoResult<String> {
   let url = module_name.parse::<Uri>().unwrap();
   let client = get_client();
-  let fetch_future = client
-    .get(url)
-    .map_err(|err| DenoError::from(err))
-    .and_then(|response| {
-      if !response.status().is_success() {
-        return Either::A(futures::future::err(errors::new(
-          errors::ErrorKind::NotFound,
-          "module not found".to_string(),
-        )));
-      }
-      Either::B(
-        response
-          .into_body()
-          .concat2()
-          .map(|body| String::from_utf8(body.to_vec()).unwrap())
-          .map_err(|err| DenoError::from(err)),
-      )
-    });
+  // TODO(kevinkassimo): consider set a max redirection counter
+  // to avoid bouncing between 2 or more urls
+  let fetch_future = loop_fn((client, Some(url)), |(client, maybe_url)| {
+    let url = maybe_url.expect("target url should not be None");
+    client
+      .get(url)
+      .map_err(|err| DenoError::from(err))
+      .and_then(|response| {
+        if response.status().is_redirection() {
+          let new_url_string = response
+            .headers()
+            .get("location")
+            .expect("url redirection should provide 'location' header")
+            .to_str()
+            .unwrap()
+            .to_string();
+          debug!("Redirecting to {}...", &new_url_string);
+          let maybe_new_url = Some(
+            new_url_string
+              .parse::<Uri>()
+              .expect("provided redirect url should be a valid url"),
+          );
+          return Ok(Loop::Continue((client, maybe_new_url)));
+        }
+        if !response.status().is_success() {
+          return Err(errors::new(
+            errors::ErrorKind::NotFound,
+            "module not found".to_string(),
+          ));
+        }
+        Ok(Loop::Break(response))
+      })
+  }).and_then(|response| {
+    response
+      .into_body()
+      .concat2()
+      .map(|body| String::from_utf8(body.to_vec()).unwrap())
+      .map_err(|err| DenoError::from(err))
+  });
+
   tokio_util::block_on(fetch_future)
 }
 
@@ -63,3 +83,13 @@ fn test_fetch_sync_string() {
     assert!(p.len() > 1);
   });
 }
+
+#[test]
+fn test_fetch_sync_string_with_redirect() {
+  // Relies on external http server. See tools/http_server.py
+  tokio_util::init(|| {
+    let p = fetch_sync_string("http://127.0.0.1:4546/package.json").unwrap();
+    println!("package.json len {}", p.len());
+    assert!(p.len() > 1);
+  });
+}
diff --git a/tests/017_import_redirect.ts b/tests/017_import_redirect.ts
new file mode 100644
index 000000000..22003e9dc
--- /dev/null
+++ b/tests/017_import_redirect.ts
@@ -0,0 +1,5 @@
+// http -> https redirect would happen:
+// tslint:disable-next-line:max-line-length
+import { printHello } from "http://gist.githubusercontent.com/ry/f12b2aa3409e6b52645bc346a9e22929/raw/79318f239f51d764384a8bded8d7c6a833610dde/print_hello.ts";
+
+printHello();
diff --git a/tests/017_import_redirect.ts.out b/tests/017_import_redirect.ts.out
new file mode 100644
index 000000000..d1ec08c42
--- /dev/null
+++ b/tests/017_import_redirect.ts.out
@@ -0,0 +1,2 @@
+Downloading http://gist.githubusercontent.com/ry/f12b2aa3409e6b52645bc346a9e22929/raw/79318f239f51d764384a8bded8d7c6a833610dde/print_hello.ts
+Hello
diff --git a/tools/http_server.py b/tools/http_server.py
index fdb8686cd..d33f24d5d 100755
--- a/tools/http_server.py
+++ b/tools/http_server.py
@@ -9,6 +9,7 @@ from util import root_path
 from time import sleep
 
 PORT = 4545
+REDIRECT_PORT = 4546
 
 
 def server():
@@ -20,11 +21,35 @@ def server():
     return s
 
 
+def redirect_server():
+    os.chdir(root_path)
+    target_host = "http://localhost:%d" % PORT
+
+    class RedirectHandler(SimpleHTTPServer.SimpleHTTPRequestHandler):
+        def do_GET(self):
+            self.send_response(301)
+            self.send_header('Location', target_host + self.path)
+            self.end_headers()
+
+    Handler = RedirectHandler
+    SocketServer.TCPServer.allow_reuse_address = True
+    s = SocketServer.TCPServer(("", REDIRECT_PORT), Handler)
+    print "Deno redirect server http://localhost:%d/ -> http://localhost:%d/" % (
+        REDIRECT_PORT, PORT)
+    return s
+
+
 def spawn():
+    # Main http server
     s = server()
     thread = Thread(target=s.serve_forever)
     thread.daemon = True
     thread.start()
+    # Redirect server
+    rs = redirect_server()
+    r_thread = Thread(target=rs.serve_forever)
+    r_thread.daemon = True
+    r_thread.start()
     sleep(1)  # TODO I'm too lazy to figure out how to do this properly.
     return thread