Added incremental XMLHttpRequest updates

Summary:
@public

Previously, our XMLHttpRequest implementation would only update the readyState when the download was fully completed. This diff adds support for receiving incremental data updates as the download happens, which can be monitored by adding the onreadystatechange event handler.

As a performance optimization, incremental data updates are only sent if the onreadystatechanged handler has been set in the JS, otherwise it just sends the whole data block once download is complete, as before.

Test Plan:
* Run the UIExplorer XMLHttpRequest example (in both OSS and Catalyst) to see incremental downloads working.
* Run the Movies app to see regular (non-incremental) downloads in action
* Run any network-based app in Catalyst shell to verify RKDataManager still works

Examples/UIExplorer/UIExplorerList.js

@@ -77,6 +77,7 @@ var APIS = [
   require('./StatusBarIOSExample'),
   require('./TimerExample'),
   require('./VibrationIOSExample'),
+  require('./XHRExample'),
 ];
 
 var ds = new ListView.DataSource({

Examples/UIExplorer/XHRExample.js

@@ -0,0 +1,131 @@
+/**
+ * The examples provided by Facebook are for non-commercial testing and
+ * evaluation purposes only.
+ *
+ * Facebook reserves all rights not expressly granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON INFRINGEMENT. IN NO EVENT SHALL
+ * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * @flow
+ */
+'use strict';
+
+var React = require('react-native');
+var {
+  ProgressViewIOS,
+  StyleSheet,
+  View,
+  Text,
+  TouchableHighlight,
+} = React;
+
+class Downloader extends React.Component {
+
+  xhr: XMLHttpRequest;
+  cancelled: boolean;
+
+  constructor(props) {
+    super(props);
+    this.cancelled = false;
+    this.state = {
+      downloading: false,
+      contentSize: 1,
+      downloaded: 0,
+    };
+  }
+
+  download() {
+    this.xhr && this.xhr.abort();
+
+    var xhr = this.xhr || new XMLHttpRequest();
+    xhr.onreadystatechange = () => {
+      if (xhr.readyState === xhr.HEADERS_RECEIVED) {
+        var contentSize = parseInt(xhr.getResponseHeader('Content-Length'), 10);
+        this.setState({
+          contentSize: contentSize,
+          downloaded: 0,
+        });
+      } else if (xhr.readyState === xhr.LOADING) {
+        this.setState({
+          downloaded: xhr.responseText.length,
+        });
+      } else if (xhr.readyState === xhr.DONE) {
+        this.setState({
+          downloading: false,
+        });
+        if (this.cancelled) {
+          this.cancelled = false;
+          return;
+        }
+        if (xhr.status === 200) {
+          alert('Download complete!');
+        } else if (xhr.status !== 0) {
+          alert('Error: Server returned HTTP status of ' + xhr.status + ' ' + xhr.responseText);
+        } else {
+          alert('Error: ' + xhr.responseText);
+        }
+      }
+    };
+    xhr.open('GET', 'http://www.gutenberg.org/cache/epub/100/pg100.txt');
+    xhr.send();
+    this.xhr = xhr;
+
+    this.setState({downloading: true});
+  }
+
+  componentWillUnmount() {
+    this.cancelled = true;
+    this.xhr && this.xhr.abort();
+  }
+
+  render() {
+    var button = this.state.downloading ? (
+      <View style={styles.wrapper}>
+        <View style={styles.button}>
+          <Text>Downloading...</Text>
+        </View>
+      </View>
+    ) : (
+      <TouchableHighlight
+        style={styles.wrapper}
+        onPress={this.download.bind(this)}>
+        <View style={styles.button}>
+         <Text>Download 5MB Text File</Text>
+        </View>
+      </TouchableHighlight>
+    );
+
+    return (
+      <View>
+        {button}
+        <ProgressViewIOS progress={(this.state.downloaded / this.state.contentSize)}/>
+      </View>
+    );
+  }
+}
+
+exports.framework = 'React';
+exports.title = 'XMLHttpRequest';
+exports.description = 'XMLHttpRequest';
+exports.examples = [{
+  title: 'File Download',
+  render() {
+    return <Downloader/>;
+  }
+}];
+
+var styles = StyleSheet.create({
+  wrapper: {
+    borderRadius: 5,
+    marginBottom: 5,
+  },
+  button: {
+    backgroundColor: '#eeeeee',
+    padding: 10,
+  },
+});

Libraries/JavaScriptAppEngine/Initialization/InitializeJavaScriptAppEngine.js

@@ -85,7 +85,7 @@ function setUpAlert() {
       var alertOpts = {
         title: 'Alert',
         message: '' + text,
-        buttons: [{'cancel': 'Okay'}],
+        buttons: [{'cancel': 'OK'}],
       };
       RCTAlertManager.alertWithArgs(alertOpts, null);
     };

Libraries/Network/RCTDataManager.m

@@ -11,10 +11,21 @@
 
 #import "RCTAssert.h"
 #import "RCTConvert.h"
+#import "RCTEventDispatcher.h"
 #import "RCTLog.h"
 #import "RCTUtils.h"
 
+@interface RCTDataManager () <NSURLSessionDataDelegate>
+
+@end
+
 @implementation RCTDataManager
+{
+  NSURLSession *_session;
+  NSOperationQueue *_callbackQueue;
+}
+
+@synthesize bridge = _bridge;
 
 RCT_EXPORT_MODULE()
 
@@ -24,6 +35,7 @@ RCT_EXPORT_MODULE()
  */
 RCT_EXPORT_METHOD(queryData:(NSString *)queryType
                   withQuery:(NSDictionary *)query
+                  sendIncrementalUpdates:(BOOL)incrementalUpdates
                   responseSender:(RCTResponseSenderBlock)responseSender)
 {
   if ([queryType isEqualToString:@"http"]) {
@@ -35,41 +47,30 @@ RCT_EXPORT_METHOD(queryData:(NSString *)queryType
     request.allHTTPHeaderFields = [RCTConvert NSDictionary:query[@"headers"]];
     request.HTTPBody = [RCTConvert NSData:query[@"data"]];
 
-    // Build data task
+    // Create session if one doesn't already exist
-    NSURLSessionDataTask *task = [[NSURLSession sharedSession] dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *connectionError) {
+    if (!_session) {
-
+      _callbackQueue = [[NSOperationQueue alloc] init];
-      NSHTTPURLResponse *httpResponse = nil;
+      NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
-      if ([response isKindOfClass:[NSHTTPURLResponse class]]) {
+      _session = [NSURLSession sessionWithConfiguration:configuration
-        // Might be a local file request
+                                               delegate:self
-        httpResponse = (NSHTTPURLResponse *)response;
+                                          delegateQueue:_callbackQueue];
     }
 
-      // Build response
+    __block NSURLSessionDataTask *task;
-      NSArray *responseJSON;
+    if (incrementalUpdates) {
-      if (connectionError == nil) {
+      task = [_session dataTaskWithRequest:request];
-        NSStringEncoding encoding = NSUTF8StringEncoding;
-        if (response.textEncodingName) {
-          CFStringEncoding cfEncoding = CFStringConvertIANACharSetNameToEncoding((CFStringRef)response.textEncodingName);
-          encoding = CFStringConvertEncodingToNSStringEncoding(cfEncoding);
-        }
-        responseJSON = @[
-          @(httpResponse.statusCode ?: 200),
-          httpResponse.allHeaderFields ?: @{},
-          [[NSString alloc] initWithData:data encoding:encoding] ?: @"",
-        ];
     } else {
-        responseJSON = @[
+      task = [_session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
-          @(httpResponse.statusCode),
+        RCTSendResponseEvent(_bridge, task);
-          httpResponse.allHeaderFields ?: @{},
+        if (!error) {
-          connectionError.localizedDescription ?: [NSNull null],
+          RCTSendDataEvent(_bridge, task, data);
-        ];
+        }
+        RCTSendCompletionEvent(_bridge, task, error);
+      }];
     }
 
-      // Send response (won't be sent on same thread as caller)
+    // Build data task
-      responseSender(responseJSON);
+    responseSender(@[@(task.taskIdentifier)]);
-
-    }];
-
     [task resume];
 
   } else {
@@ -78,4 +79,78 @@ RCT_EXPORT_METHOD(queryData:(NSString *)queryType
   }
 }
 
+#pragma mark - URLSession delegate
+
+- (void)URLSession:(NSURLSession *)session
+          dataTask:(NSURLSessionDataTask *)task
+didReceiveResponse:(NSURLResponse *)response
+ completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler
+{
+  RCTSendResponseEvent(_bridge, task);
+  completionHandler(NSURLSessionResponseAllow);
+}
+
+- (void)URLSession:(NSURLSession *)session
+          dataTask:(NSURLSessionDataTask *)task
+    didReceiveData:(NSData *)data
+{
+  RCTSendDataEvent(_bridge, task, data);
+}
+
+- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error
+{
+  RCTSendCompletionEvent(_bridge, task, error);
+}
+
+#pragma mark - Build responses
+
+static void RCTSendResponseEvent(RCTBridge *bridge, NSURLSessionTask *task)
+{
+  NSURLResponse *response = task.response;
+  NSHTTPURLResponse *httpResponse = nil;
+  if ([response isKindOfClass:[NSHTTPURLResponse class]]) {
+    // Might be a local file request
+    httpResponse = (NSHTTPURLResponse *)response;
+  }
+
+  NSArray *responseJSON = @[@(task.taskIdentifier),
+                            @(httpResponse.statusCode ?: 200),
+                            httpResponse.allHeaderFields ?: @{},
+                            ];
+
+  [bridge.eventDispatcher sendDeviceEventWithName:@"didReceiveNetworkResponse"
+                                             body:responseJSON];
+}
+
+static void RCTSendDataEvent(RCTBridge *bridge, NSURLSessionDataTask *task, NSData *data)
+{
+  // Get text encoding
+  NSURLResponse *response = task.response;
+  NSStringEncoding encoding = NSUTF8StringEncoding;
+  if (response.textEncodingName) {
+    CFStringEncoding cfEncoding = CFStringConvertIANACharSetNameToEncoding((CFStringRef)response.textEncodingName);
+    encoding = CFStringConvertEncodingToNSStringEncoding(cfEncoding);
+  }
+
+  NSString *responseText = [[NSString alloc] initWithData:data encoding:encoding];
+  if (!responseText && data.length) {
+    RCTLogError(@"Received data was invalid.");
+    return;
+  }
+
+  NSArray *responseJSON = @[@(task.taskIdentifier), responseText ?: @""];
+  [bridge.eventDispatcher sendDeviceEventWithName:@"didReceiveNetworkData"
+                                             body:responseJSON];
+}
+
+static void RCTSendCompletionEvent(RCTBridge *bridge, NSURLSessionTask *task, NSError *error)
+{
+  NSArray *responseJSON = @[@(task.taskIdentifier),
+                            error.localizedDescription ?: [NSNull null],
+                            ];
+
+  [bridge.eventDispatcher sendDeviceEventWithName:@"didCompleteNetworkResponse"
+                                             body:responseJSON];
+}
+
 @end

Libraries/Network/XMLHttpRequest.ios.js

@@ -12,11 +12,73 @@
 'use strict';
 
 var RCTDataManager = require('NativeModules').DataManager;
+var RCTDeviceEventEmitter = require('RCTDeviceEventEmitter');
 
 var XMLHttpRequestBase = require('XMLHttpRequestBase');
 
 class XMLHttpRequest extends XMLHttpRequestBase {
 
+  _requestId: ?number;
+  _subscriptions: [any];
+
+  constructor() {
+    super();
+    this._requestId = null;
+    this._subscriptions = [];
+  }
+
+  _didCreateRequest(requestId: number): void {
+    this._requestId = requestId;
+    this._subscriptions.push(RCTDeviceEventEmitter.addListener(
+      'didReceiveNetworkResponse',
+      (args) => this._didReceiveResponse.call(this, args[0], args[1], args[2])
+    ));
+    this._subscriptions.push(RCTDeviceEventEmitter.addListener(
+      'didReceiveNetworkData',
+      (args) =>  this._didReceiveData.call(this, args[0], args[1])
+    ));
+    this._subscriptions.push(RCTDeviceEventEmitter.addListener(
+      'didCompleteNetworkResponse',
+      (args) => this._didCompleteResponse.apply(this, args[0], args[1])
+    ));
+  }
+
+  _didReceiveResponse(requestId: number, status: number, responseHeaders: ?Object): void {
+    if (requestId === this._requestId) {
+      this.status = status;
+      this.setResponseHeaders(responseHeaders);
+      this.setReadyState(this.HEADERS_RECEIVED);
+    }
+  }
+
+  _didReceiveData(requestId: number, responseText: string): void {
+    if (requestId === this._requestId) {
+      if (!this.responseText) {
+        this.responseText = responseText;
+      } else {
+        this.responseText += responseText;
+      }
+      this.setReadyState(this.LOADING);
+    }
+  }
+
+  _didCompleteResponse(requestId: number, error: string): void {
+    if (requestId === this._requestId) {
+      this.responseText = error;
+      this._clearSubscriptions();
+      this._requestId = null;
+      this.setReadyState(this.DONE);
+    }
+  }
+
+  _clearSubscriptions(): void {
+    for (var i = 0; i < this._subscriptions.length; i++) {
+      var sub = this._subscriptions[i];
+      sub.remove();
+    }
+    this._subscriptions = [];
+  }
+
   sendImpl(method: ?string, url: ?string, headers: Object, data: any): void {
     RCTDataManager.queryData(
       'http',
@@ -26,11 +88,16 @@ class XMLHttpRequest extends XMLHttpRequestBase {
         data: data,
         headers: headers,
       },
-      this.callback.bind(this)
+      this.onreadystatechange ? true : false,
+      this._didCreateRequest.bind(this)
     );
   }
 
   abortImpl(): void {
+    if (this._requestId) {
+      this._clearSubscriptions();
+      this._requestId = null;
+    }
     console.warn(
       'XMLHttpRequest: abort() cancels JS callbacks ' +
       'but not native HTTP request.'

Libraries/Network/XMLHttpRequestBase.js

@@ -1,8 +1,13 @@
 /**
- * Copyright 2004-present Facebook. All Rights Reserved.
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
  *
- * @flow
  * @providesModule XMLHttpRequestBase
+ * @flow
  */
 'use strict';
 
@@ -30,6 +35,7 @@ class XMLHttpRequestBase {
   _headers: Object;
   _sent: boolean;
   _aborted: boolean;
+  _lowerCaseResponseHeaders: Object;
 
   constructor() {
     this.UNSENT = 0;
@@ -38,46 +44,52 @@ class XMLHttpRequestBase {
     this.LOADING = 3;
     this.DONE = 4;
 
-    this.onreadystatechange = undefined;
+    this.onreadystatechange = null;
-    this.upload = undefined; /* Upload not supported */
+    this.onload = null;
-    this.readyState = this.UNSENT;
+    this.upload = undefined; /* Upload not supported yet */
-    this.responseHeaders = undefined;
-    this.responseText = undefined;
-    this.status = 0;
 
+    this._reset();
     this._method = null;
     this._url = null;
-    this._headers = {};
-    this._sent = false;
     this._aborted = false;
   }
 
+  _reset() {
+    this.readyState = this.UNSENT;
+    this.responseHeaders = undefined;
+    this.responseText = '';
+    this.status = 0;
+
+    this._headers = {};
+    this._sent = false;
+    this._lowerCaseResponseHeaders = {};
+  }
+
   getAllResponseHeaders(): ?string {
-    if (this.responseHeaders) {
+    if (!this.responseHeaders) {
-      var headers = [];
+      // according to the spec, return null if no response has been received
-      for (var headerName in this.responseHeaders) {
-        headers.push(headerName + ': ' + this.responseHeaders[headerName]);
-      }
-      return headers.join('\n');
-    }
-    // according to the spec, return null <==> no response has been received
       return null;
     }
+    var headers = this.responseHeaders || {};
+    return Object.keys(headers).map((headerName) => {
+      return headerName + ': ' + headers[headerName];
+    }).join('\n');
+  }
 
   getResponseHeader(header: string): ?string {
-    if (this.responseHeaders) {
+    var value = this._lowerCaseResponseHeaders[header.toLowerCase()];
-      var value = this.responseHeaders[header.toLowerCase()];
     return value !== undefined ? value : null;
   }
-    return null;
-  }
 
   setRequestHeader(header: string, value: any): void {
+    if (this.readyState !== this.OPENED) {
+      throw new Error('Request has not been opened');
+    }
     this._headers[header.toLowerCase()] = value;
   }
 
   open(method: string, url: string, async: ?boolean): void {
-    /* Other optional arguments are not supported */
+    /* Other optional arguments are not supported yet */
     if (this.readyState !== this.UNSENT) {
       throw new Error('Cannot open, already sending');
     }
@@ -85,10 +97,11 @@ class XMLHttpRequestBase {
       // async is default
       throw new Error('Synchronous http requests are not supported');
     }
+    this._reset();
     this._method = method;
     this._url = url;
     this._aborted = false;
-    this._setReadyState(this.OPENED);
+    this.setReadyState(this.OPENED);
   }
 
   sendImpl(method: ?string, url: ?string, headers: Object, data: any): void {
@@ -111,20 +124,18 @@ class XMLHttpRequestBase {
   }
 
   abort(): void {
+    this._aborted = true;
     this.abortImpl();
     // only call onreadystatechange if there is something to abort,
     // below logic is per spec
     if (!(this.readyState === this.UNSENT ||
         (this.readyState === this.OPENED && !this._sent) ||
         this.readyState === this.DONE)) {
-      this._sent = false;
+      this._reset();
-      this._setReadyState(this.DONE);
+      this.setReadyState(this.DONE);
     }
-    if (this.readyState === this.DONE) {
+    // Reset again after, in case modified in handler
-      this._sendLoad();
+    this._reset();
-    }
-    this.readyState = this.UNSENT;
-    this._aborted = true;
   }
 
   callback(status: number, responseHeaders: ?Object, responseText: string): void {
@@ -132,18 +143,22 @@ class XMLHttpRequestBase {
       return;
     }
     this.status = status;
-    // Headers should be case-insensitive
+    this.setResponseHeaders(responseHeaders);
-    var lcResponseHeaders = {};
-    for (var header in responseHeaders) {
-      lcResponseHeaders[header.toLowerCase()] = responseHeaders[header];
-    }
-    this.responseHeaders = lcResponseHeaders;
     this.responseText = responseText;
-    this._setReadyState(this.DONE);
+    this.setReadyState(this.DONE);
-    this._sendLoad();
   }
 
-  _setReadyState(newState: number): void {
+  setResponseHeaders(responseHeaders: ?Object): void {
+    this.responseHeaders = responseHeaders || null;
+    var headers = responseHeaders || {};
+    this._lowerCaseResponseHeaders =
+      Object.keys(headers).reduce((lcaseHeaders, headerName) => {
+        lcaseHeaders[headerName.toLowerCase()] = headers[headerName];
+        return headers;
+      }, {});
+  }
+
+  setReadyState(newState: number): void {
     this.readyState = newState;
     // TODO: workaround flow bug with nullable function checks
     var onreadystatechange = this.onreadystatechange;
@@ -152,6 +167,9 @@ class XMLHttpRequestBase {
       // event anywhere, let's leave it empty
       onreadystatechange(null);
     }
+    if (newState === this.DONE && !this._aborted) {
+      this._sendLoad();
+    }
   }
 
   _sendLoad(): void {