Add the http library to pub.

TBR

Review URL: https://codereview.chromium.org//11593016

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@16231 260f80e4-7a28-3924-810f-c04153c831b5

utils/pub/http.dart

@@ -0,0 +1,138 @@
+// 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.
+
+/// Helpers for dealing with HTTP.
+library http;
+
+import 'dart:io';
+import 'dart:json';
+
+// TODO(nweiz): Make this import better.
+import '../../pkg/http/lib/http.dart' as http;
+import 'curl_client.dart';
+import 'io.dart';
+import 'log.dart' as log;
+
+// TODO(nweiz): make this configurable
+/**
+ * The amount of time in milliseconds to allow HTTP requests before assuming
+ * they've failed.
+ */
+final HTTP_TIMEOUT = 30 * 1000;
+
+/// An HTTP client that transforms 40* errors and socket exceptions into more
+/// user-friendly error messages.
+class PubHttpClient extends http.BaseClient {
+  final http.Client _inner;
+
+  PubHttpClient([http.Client inner])
+    : _inner = inner == null ? new http.Client() : inner;
+
+  Future<http.StreamedResponse> send(http.BaseRequest request) {
+    // TODO(rnystrom): Log request body when it's available and plaintext, but
+    // not when it contains OAuth2 credentials.
+
+    // TODO(nweiz): remove this when issue 4061 is fixed.
+    var stackTrace;
+    try {
+      throw null;
+    } catch (_, localStackTrace) {
+      stackTrace = localStackTrace;
+    }
+
+    // TODO(nweiz): Ideally the timeout would extend to reading from the
+    // response input stream, but until issue 3657 is fixed that's not feasible.
+    return timeout(_inner.send(request).chain((streamedResponse) {
+      log.fine("Got response ${streamedResponse.statusCode} "
+               "${streamedResponse.reasonPhrase}.");
+
+      var status = streamedResponse.statusCode;
+      // 401 responses should be handled by the OAuth2 client. It's very
+      // unlikely that they'll be returned by non-OAuth2 requests.
+      if (status < 400 || status == 401) {
+        return new Future.immediate(streamedResponse);
+      }
+
+      return http.Response.fromStream(streamedResponse).transform((response) {
+        throw new PubHttpException(response);
+      });
+    }).transformException((e) {
+      if (e is SocketIOException &&
+          e.osError != null &&
+          (e.osError.errorCode == 8 ||
+           e.osError.errorCode == -2 ||
+           e.osError.errorCode == -5 ||
+           e.osError.errorCode == 11004)) {
+        throw 'Could not resolve URL "${request.url.origin}".';
+      }
+      throw e;
+    }), HTTP_TIMEOUT, 'fetching URL "${request.url}"');
+  }
+}
+
+/// The HTTP client to use for all HTTP requests.
+final httpClient = new PubHttpClient();
+
+final curlClient = new PubHttpClient(new CurlClient());
+
+/// Handles a successful JSON-formatted response from pub.dartlang.org.
+///
+/// These responses are expected to be of the form `{"success": {"message":
+/// "some message"}}`. If the format is correct, the message will be printed;
+/// otherwise an error will be raised.
+void handleJsonSuccess(http.Response response) {
+  var parsed = parseJsonResponse(response);
+  if (parsed['success'] is! Map ||
+      !parsed['success'].containsKey('message') ||
+      parsed['success']['message'] is! String) {
+    invalidServerResponse(response);
+  }
+  log.message(parsed['success']['message']);
+}
+
+/// Handles an unsuccessful JSON-formatted response from pub.dartlang.org.
+///
+/// These responses are expected to be of the form `{"error": {"message": "some
+/// message"}}`. If the format is correct, the message will be raised as an
+/// error; otherwise an [invalidServerResponse] error will be raised.
+void handleJsonError(http.Response response) {
+  var errorMap = parseJsonResponse(response);
+  if (errorMap['error'] is! Map ||
+      !errorMap['error'].containsKey('message') ||
+      errorMap['error']['message'] is! String) {
+    invalidServerResponse(response);
+  }
+  throw errorMap['error']['message'];
+}
+
+/// Parses a response body, assuming it's JSON-formatted. Throws a user-friendly
+/// error if the response body is invalid JSON, or if it's not a map.
+Map parseJsonResponse(http.Response response) {
+  var value;
+  try {
+    value = JSON.parse(response.body);
+  } catch (e) {
+    // TODO(nweiz): narrow this catch clause once issue 6775 is fixed.
+    invalidServerResponse(response);
+  }
+  if (value is! Map) invalidServerResponse(response);
+  return value;
+}
+
+/// Throws an error describing an invalid response from the server.
+void invalidServerResponse(http.Response response) {
+  throw 'Invalid server response:\n${response.body}';
+}
+
+/**
+ * Exception thrown when an HTTP operation fails.
+ */
+class PubHttpException implements Exception {
+  final http.Response response;
+
+  const PubHttpException(this.response);
+
+  String toString() => 'HTTP error ${response.statusCode}: '
+      '${response.reasonPhrase}';
+}