Show nicer errors on some server failures.

utils/pub/io.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * Helper functionality to make working with IO easier.
  */
 #library('io');
 
 #import('dart:io');
@@ skipping 110 matching lines @@
     return opened.writeString(contents).chain((ignore) {
         return opened.close().transform((ignore) => file);
     });
   });
 }
 
 /**
  * Asynchronously deletes [file], which can be a [String] or a [File]. Returns a
  * [Future] that completes when the deletion is done.
  */
-Future<Directory> deleteFile(file) {
+Future<File> deleteFile(file) {
   return new File(_getPath(file)).delete();
 }
 
 /**
  * Creates a directory [dir]. Returns a [Future] that completes when the
  * directory is created.
  */
 Future<Directory> createDir(dir) {
   dir = _getDirectory(dir);
   return dir.create();
@@ skipping 160 matching lines @@
           "HTTP request for $uri failed with status ${response.statusCode}");
     }
 
     pipeInputToInput(response.inputStream, resultStream);
   };
 
   return resultStream;
 }
 
 /**
+ * Opens an input stream for a HTTP GET request to [uri], which may be a
+ * [String] or [Uri]. Completes with the result of the request as a String.
+ */
+Future<String> httpGetString(uri) {

[nweiz, 2012/09/04 19:29:25]

Why is this method different than httpGet? Is it just because ListInputStream
doesn't support error propagation? If so, you should add a TODO here to merge
these two when issue 3657 is fixed.

[Bob Nystrom, 2012/09/04 22:14:46]

Yup.
Done.

+  uri = _getUri(uri);
+
+  var completer = new Completer<String>();
+  var client = new HttpClient();
+  var connection = client.getUrl(uri);
+
+  connection.onError = (e) {
+    // Show a friendly error if the URL couldn't be resolved.
+    if ((e is SocketIOException) && (e.osError.errorCode == 8)) {

[nweiz, 2012/09/04 19:29:25]

I don't like these unnecessary parens. I don't think it's unclear how tightly
"&&" binds.

[Bob Nystrom, 2012/09/04 22:14:46]

Done.

+      e = 'Could not resolve URL "${uri.origin}".';
+    }
+
+    completer.completeException(e);
+  };

[nweiz, 2012/09/04 19:29:25]

Shouldn't you call client.shutdown here, too?

[Bob Nystrom, 2012/09/04 22:14:46]

Done.

+
+  connection.onResponse = (response) {
+    if (response.statusCode >= 400) {
+      client.shutdown();
+      completer.completeException(
+          new HttpException(response.statusCode, response.reasonPhrase));
+      return;
+    }
+
+    var resultStream = new ListInputStream();
+    var buffer = <int>[];
+
+    response.inputStream.onClosed = () {
+      // Make sure we aren't closing in response to an error in which case
+      // we will have already completed with that exception.

[nweiz, 2012/09/04 19:29:25]

onClosed and onError should be mutually exclusive.

[Bob Nystrom, 2012/09/04 22:14:46]

They didn't seem to be. Without this check, I get a FutureAlreadyCompleted
error.

[nweiz, 2012/09/04 22:38:18]

I believe that's a bug according to
https://docs.google.com/a/google.com/document/d/1ybQCrO6fbiTdj2h37G4Sgd-rMPzp....
I think https://chromiumcodereview.appspot.com/10836177/ will fix it, though.

[Bob Nystrom, 2012/09/04 23:01:20]

The pub tests seem to pass without the check, so I removed it. I recall seeing
an error here, but maybe that was just with my own local testing.

+      if (!completer.future.isComplete) {
+        client.shutdown();
+        completer.complete(new String.fromCharCodes(buffer));
+      }
+    };
+
+    response.inputStream.onData = () {
+      buffer.addAll(response.inputStream.read());
+    };
+
+    response.inputStream.onError = (e) => completer.completeException(e);
+  };
+
+  return completer.future;
+}
+
+/**
  * Takes all input from [source] and writes it to [sink].
  *
  * [onClosed] is called when [source] is closed.
  */
 void pipeInputToInput(InputStream source, ListInputStream sink,
     [void onClosed()]) {
   source.onClosed = () {
     sink.markEndOfStream();
     if (onClosed != null) onClosed();
   };
@@ skipping 122 matching lines @@
   stream.pipe(process.stdin);
   process.stdout.pipe(stdout, close: false);
   process.stderr.pipe(stderr, close: false);
 
   process.onExit = completer.complete;
   process.onError = completer.completeException;
   return completer.future.transform((exitCode) => exitCode == 0);
 }
 
 /**
+ * Exception thrown when an HTTP operation fails.
+ */
+class HttpException implements Exception {
+  final int statusCode;
+  final String reason;
+
+  const HttpException(this.statusCode, this.reason);
+}
+
+/**
  * Contains the results of invoking a [Process] and waiting for it to complete.
  */
 class PubProcessResult {
   final List<String> stdout;
   final List<String> stderr;
   final int exitCode;
 
   const PubProcessResult(this.stdout, this.stderr, this.exitCode);
 
   bool get success => exitCode == 0;
@@ skipping 20 matching lines @@
   return new Directory(entry);
 }
 
 /**
  * Gets a [Uri] for [uri], which can either already be one, or be a [String].
  */
 Uri _getUri(uri) {
   if (uri is Uri) return uri;
   return new Uri.fromString(uri);
 }