Disable GZIP in pub serve’s HTTP server.

sdk/lib/_internal/pub/lib/src/barback/base_server.dart

Index: sdk/lib/_internal/pub/lib/src/barback/base_server.dart
diff --git a/sdk/lib/_internal/pub/lib/src/barback/base_server.dart b/sdk/lib/_internal/pub/lib/src/barback/base_server.dart
index 81559214abce462c97d6879dd8914e8607b1fd15..95dc355562341cbab81f716af11186c0107c24e1 100644
--- a/sdk/lib/_internal/pub/lib/src/barback/base_server.dart
+++ b/sdk/lib/_internal/pub/lib/src/barback/base_server.dart
@@ -45,6 +45,7 @@ abstract class BaseServer<T> {
   BaseServer(this.environment, this._server) {
     shelf_io.serveRequests(Chain.track(_server), const shelf.Pipeline()
         .addMiddleware(shelf.createMiddleware(errorHandler: _handleError))
+        .addMiddleware(shelf.createMiddleware(responseHandler: _disableGzip))
         .addHandler(handleRequest));
   }
 
@@ -121,4 +122,20 @@ abstract class BaseServer<T> {
     close();
     return new shelf.Response.internalServerError();
   }
+
+  /// Disable GZIP responses.
+  ///
+  /// This is primarily to optimize pub's startup. Since the transformer
+  /// plug-ins are loaded over HTTP, we pay the hit to GZIP encode and decode
+  /// them. Disabling this improves startup time by about 5% on my test.
+  ///
+  // TODO(rnystrom): Remove this when #5187 is fixed and we don't have to use

[Anders Johnsen, 2014/06/03 07:08:49]

Due to the fact that barback is always run localhost->localhost, and never in a
production environment, I would argue that it never should use gzip, even when
the above issue is fixed.

[nweiz, 2014/06/03 18:07:32]

When the above issue is fixed, we won't be using HTTP at all.

[Anders Johnsen, 2014/06/03 18:37:18]

You will still serve http content to the browser, right?

[nweiz, 2014/06/03 19:07:35]

Ah, good point, you're probably right that that should continue to be
un-gzipped.

+  // HTTP for isolates.
+  _disableGzip(shelf.Response response) {
+    if (!response.headers.containsKey('Content-Encoding')) {
+      return response.change(headers: {'Content-Encoding': ''});
+    }
+
+    return response;
+  }
 }