Implement a postMessage function and an onMessage event for webviews …

Summary: JS API very similar to web workers and node's child process. Work has been done by somebody else for the Android implementation over at facebook#7020, so we'd need to have these in sync before anything gets merged. I've made a prop `messagingEnabled` to be more explicit about creating globals—it might be sufficient to just check for an onMessage handler though. ![screen shot 2016-09-06 at 10 28 23](https://cloud.githubusercontent.com/assets/7275322/18268669/b1a12348-741c-11e6-91a1-ad39d5a8bc03.png) Closes facebook#9762 Differential Revision: D4008260 fbshipit-source-id: 84b1afafbc0ab1edc3dfbf1a8fb870218e171a4c
eritter · Sep 11, 2019 · 4358c13 · 4358c13
1 parent 953f9b8
commit 4358c13
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Showing 11 changed files with 338 additions and 2 deletions.
diff --git a/Examples/UIExplorer/js/WebViewExample.js b/Examples/UIExplorer/js/WebViewExample.js
@@ -217,6 +217,53 @@ class ScaledWebView extends React.Component {
   }
 }
 
+class MessagingTest extends React.Component {
+  webview = null
+
+  state = {
+    messagesReceivedFromWebView: 0,
+    message: '',
+  }
+
+  onMessage = e => this.setState({
+    messagesReceivedFromWebView: this.state.messagesReceivedFromWebView + 1,
+    message: e.nativeEvent.data,
+  })
+
+  postMessage = () => {
+    if (this.webview) {
+      this.webview.postMessage('"Hello" from React Native!');
+    }
+  }
+
+  render(): ReactElement<any> {
+    const {messagesReceivedFromWebView, message} = this.state;
+
+    return (
+      <View style={[styles.container, { height: 200 }]}>
+        <View style={styles.container}>
+          <Text>Messages received from web view: {messagesReceivedFromWebView}</Text>
+          <Text>{message || '(No message)'}</Text>
+          <View style={styles.buttons}>
+            <Button text="Send Message to Web View" enabled onPress={this.postMessage} />
+          </View>
+        </View>
+        <View style={styles.container}>
+          <WebView
+            ref={webview => { this.webview = webview; }}
+            style={{
+              backgroundColor: BGWASH,
+              height: 100,
+            }}
+            source={require('./messagingtest.html')}
+            onMessage={this.onMessage}
+          />
+        </View>
+      </View>
+    );
+  }
+}
+
 var styles = StyleSheet.create({
   container: {
     flex: 1,
@@ -391,5 +438,9 @@ exports.examples = [
         />
       );
     }
+  },
+  {
+    title: 'Mesaging Test',
+    render(): ReactElement<any> { return <MessagingTest />; }
   }
 ];
diff --git a/Examples/UIExplorer/js/messagingtest.html b/Examples/UIExplorer/js/messagingtest.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Messaging Test</title>
+    <meta http-equiv="content-type" content="text/html; charset=utf-8">
+    <meta name="viewport" content="width=320, user-scalable=no">
+  </head>
+  <body>
+    <p>Messages recieved from React Native: 0</p>
+    <p>(No messages)</p>
+    <button type="button">
+      Send message to React Native
+    </button>
+  </body>
+  <script>
+    var messagesReceivedFromReactNative = 0;
+    document.addEventListener('message', function(e) {
+      messagesReceivedFromReactNative += 1;
+      document.getElementsByTagName('p')[0].innerHTML =
+        'Messages recieved from React Native: ' + messagesReceivedFromReactNative;
+      document.getElementsByTagName('p')[1].innerHTML = e.data;
+    });
+
+    document.getElementsByTagName('button')[0].addEventListener('click', function() {
+      window.postMessage('"Hello" from the web view');
+    });
+  </script>
+</html>
diff --git a/Libraries/Components/WebView/WebView.android.js b/Libraries/Components/WebView/WebView.android.js
@@ -58,6 +58,7 @@ class WebView extends React.Component {
     automaticallyAdjustContentInsets: PropTypes.bool,
     contentInset: EdgeInsetsPropType,
     onNavigationStateChange: PropTypes.func,
+    onMessage: PropTypes.func,
     onContentSizeChange: PropTypes.func,
     startInLoadingState: PropTypes.bool, // force WebView to show loadingView on first load
     style: View.propTypes.style,
@@ -218,6 +219,8 @@ class WebView extends React.Component {
         userAgent={this.props.userAgent}
         javaScriptEnabled={this.props.javaScriptEnabled}
         domStorageEnabled={this.props.domStorageEnabled}
+        messagingEnabled={typeof this.props.onMessage === 'function'}
+        onMessage={this.onMessage}
         contentInset={this.props.contentInset}
         automaticallyAdjustContentInsets={this.props.automaticallyAdjustContentInsets}
         onContentSizeChange={this.props.onContentSizeChange}
@@ -268,6 +271,14 @@ class WebView extends React.Component {
     );
   };
 
+  postMessage = (data) => {
+    UIManager.dispatchViewManagerCommand(
+      this.getWebViewHandle(),
+      UIManager.RCTWebView.Commands.postMessage,
+      [String(data)]
+    );
+  };
+
   /**
    * We return an event with a bunch of fields including:
    *  url, title, loading, canGoBack, canGoForward
@@ -310,9 +321,18 @@ class WebView extends React.Component {
     });
     this.updateNavigationState(event);
   };
+
+  onMessage = (event: Event) => {
+    var {onMessage} = this.props;
+    onMessage && onMessage(event);
+  }
 }
 
-var RCTWebView = requireNativeComponent('RCTWebView', WebView);
+var RCTWebView = requireNativeComponent('RCTWebView', WebView, {
+  nativeOnly: {
+    messagingEnabled: PropTypes.bool,
+  },
+});
 
 var styles = StyleSheet.create({
   container: {

diff --git a/Libraries/Components/WebView/WebView.ios.js b/Libraries/Components/WebView/WebView.ios.js
@@ -235,6 +235,16 @@ class WebView extends React.Component {
      * Function that is invoked when the `WebView` loading starts or ends.
      */
     onNavigationStateChange: PropTypes.func,
+    /**
+     * A function that is invoked when the webview calls `window.postMessage`.
+     * Setting this property will inject a `postMessage` global into your
+     * webview, but will still call pre-existing values of `postMessage`.
+     *
+     * `window.postMessage` accepts one argument, `data`, which will be
+     * available on the event object, `event.nativeEvent.data`. `data`
+     * must be a string.
+     */
+    onMessage: PropTypes.func,
     /**
      * Boolean value that forces the `WebView` to show the loading view
      * on the first load.
@@ -382,6 +392,8 @@ class WebView extends React.Component {
       source.uri = this.props.url;
     }
 
+    const messagingEnabled = typeof this.props.onMessage === 'function';
+
     var webView =
       <RCTWebView
         ref={RCT_WEBVIEW_REF}
@@ -397,6 +409,8 @@ class WebView extends React.Component {
         onLoadingStart={this._onLoadingStart}
         onLoadingFinish={this._onLoadingFinish}
         onLoadingError={this._onLoadingError}
+        messagingEnabled={messagingEnabled}
+        onMessage={this._onMessage}
         onShouldStartLoadWithRequest={onShouldStartLoadWithRequest}
         scalesPageToFit={this.props.scalesPageToFit}
         allowsInlineMediaPlayback={this.props.allowsInlineMediaPlayback}
@@ -457,6 +471,24 @@ class WebView extends React.Component {
     );
   };
 
+  /**
+   * Posts a message to the web view, which will emit a `message` event.
+   * Accepts one argument, `data`, which must be a string.
+   *
+   * In your webview, you'll need to something like the following.
+   *
+   * ```js
+   * document.addEventListener('message', e => { document.title = e.data; });
+   * ```
+   */
+  postMessage = (data) => {
+    UIManager.dispatchViewManagerCommand(
+      this.getWebViewHandle(),
+      UIManager.RCTWebView.Commands.postMessage,
+      [String(data)]
+    );
+  };
+
   /**
    * We return an event with a bunch of fields including:
    *  url, title, loading, canGoBack, canGoForward
@@ -502,13 +534,20 @@ class WebView extends React.Component {
     });
     this._updateNavigationState(event);
   };
+
+  _onMessage = (event: Event) => {
+    var {onMessage} = this.props;
+    onMessage && onMessage(event);
+  }
 }
 
 var RCTWebView = requireNativeComponent('RCTWebView', WebView, {
   nativeOnly: {
     onLoadingStart: true,
     onLoadingError: true,
     onLoadingFinish: true,
+    onMessage: true,
+    messagingEnabled: PropTypes.bool,
   },
 });
 

diff --git a/React/Views/RCTWebView.h b/React/Views/RCTWebView.h
@@ -34,12 +34,14 @@ shouldStartLoadForRequest:(NSMutableDictionary<NSString *, id> *)request
 @property (nonatomic, copy) NSDictionary *source;
 @property (nonatomic, assign) UIEdgeInsets contentInset;
 @property (nonatomic, assign) BOOL automaticallyAdjustContentInsets;
+@property (nonatomic, assign) BOOL messagingEnabled;
 @property (nonatomic, copy) NSString *injectedJavaScript;
 @property (nonatomic, assign) BOOL scalesPageToFit;
 
 - (void)goForward;
 - (void)goBack;
 - (void)reload;
 - (void)stopLoading;
+- (void)postMessage:(NSString *)message;
 
 @end
diff --git a/React/Views/RCTWebView.m b/React/Views/RCTWebView.m
@@ -20,13 +20,15 @@
 #import "UIView+React.h"
 
 NSString *const RCTJSNavigationScheme = @"react-js-navigation";
+NSString *const RCTJSPostMessageHost = @"postMessage";
 
 @interface RCTWebView () <UIWebViewDelegate, RCTAutoInsetsProtocol>
 
 @property (nonatomic, copy) RCTDirectEventBlock onLoadingStart;
 @property (nonatomic, copy) RCTDirectEventBlock onLoadingFinish;
 @property (nonatomic, copy) RCTDirectEventBlock onLoadingError;
 @property (nonatomic, copy) RCTDirectEventBlock onShouldStartLoadWithRequest;
+@property (nonatomic, copy) RCTDirectEventBlock onMessage;
 
 @end
 
@@ -82,6 +84,18 @@ - (void)stopLoading
   [_webView stopLoading];
 }
 
+- (void)postMessage:(NSString *)message
+{
+  NSDictionary *eventInitDict = @{
+    @"data": message,
+  };
+  NSString *source = [NSString
+    stringWithFormat:@"document.dispatchEvent(new MessageEvent('message', %@));",
+    RCTJSONStringify(eventInitDict, NULL)
+  ];
+  [_webView stringByEvaluatingJavaScriptFromString:source];
+}
+
 - (void)setSource:(NSDictionary *)source
 {
   if (![_source isEqualToDictionary:source]) {
@@ -221,6 +235,18 @@ - (BOOL)webView:(__unused UIWebView *)webView shouldStartLoadWithRequest:(NSURLR
     }
   }
 
+  if (isJSNavigation && [request.URL.host isEqualToString:RCTJSPostMessageHost]) {
+    NSString *data = request.URL.query;
+    data = [data stringByReplacingOccurrencesOfString:@"+" withString:@" "];
+    data = [data stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
+
+    NSMutableDictionary<NSString *, id> *event = [self baseEvent];
+    [event addEntriesFromDictionary: @{
+      @"data": data,
+    }];
+    _onMessage(event);
+  }
+
   // JS Navigation handler
   return !isJSNavigation;
 }
@@ -248,6 +274,26 @@ - (void)webView:(__unused UIWebView *)webView didFailLoadWithError:(NSError *)er
 
 - (void)webViewDidFinishLoad:(UIWebView *)webView
 {
+  if (_messagingEnabled) {
+    #if RCT_DEV
+    // See isNative in lodash
+    NSString *testPostMessageNative = @"String(window.postMessage) === String(Object.hasOwnProperty).replace('hasOwnProperty', 'postMessage')";
+    BOOL postMessageIsNative = [
+      [webView stringByEvaluatingJavaScriptFromString:testPostMessageNative]
+      isEqualToString:@"true"
+    ];
+    if (!postMessageIsNative) {
+      RCTLogError(@"Setting onMessage on a WebView overrides existing values of window.postMessage, but a previous value was defined");
+    }
+    #endif
+    NSString *source = [NSString stringWithFormat:
+      @"window.originalPostMessage = window.postMessage;"
+      "window.postMessage = function(data) {"
+        "window.location = '%@://%@?' + encodeURIComponent(String(data));"
+      "};", RCTJSNavigationScheme, RCTJSPostMessageHost
+    ];
+    [webView stringByEvaluatingJavaScriptFromString:source];
+  }
   if (_injectedJavaScript != nil) {
     NSString *jsEvaluationValue = [webView stringByEvaluatingJavaScriptFromString:_injectedJavaScript];
 

diff --git a/React/Views/RCTWebViewManager.m b/React/Views/RCTWebViewManager.m
@@ -38,12 +38,14 @@ - (UIView *)view
 RCT_REMAP_VIEW_PROPERTY(scrollEnabled, _webView.scrollView.scrollEnabled, BOOL)
 RCT_REMAP_VIEW_PROPERTY(decelerationRate, _webView.scrollView.decelerationRate, CGFloat)
 RCT_EXPORT_VIEW_PROPERTY(scalesPageToFit, BOOL)
+RCT_EXPORT_VIEW_PROPERTY(messagingEnabled, BOOL)
 RCT_EXPORT_VIEW_PROPERTY(injectedJavaScript, NSString)
 RCT_EXPORT_VIEW_PROPERTY(contentInset, UIEdgeInsets)
 RCT_EXPORT_VIEW_PROPERTY(automaticallyAdjustContentInsets, BOOL)
 RCT_EXPORT_VIEW_PROPERTY(onLoadingStart, RCTDirectEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(onLoadingFinish, RCTDirectEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(onLoadingError, RCTDirectEventBlock)
+RCT_EXPORT_VIEW_PROPERTY(onMessage, RCTDirectEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(onShouldStartLoadWithRequest, RCTDirectEventBlock)
 RCT_REMAP_VIEW_PROPERTY(allowsInlineMediaPlayback, _webView.allowsInlineMediaPlayback, BOOL)
 RCT_REMAP_VIEW_PROPERTY(mediaPlaybackRequiresUserAction, _webView.mediaPlaybackRequiresUserAction, BOOL)
@@ -97,6 +99,18 @@ - (UIView *)view
   }];
 }
 
+RCT_EXPORT_METHOD(postMessage:(nonnull NSNumber *)reactTag message:(NSString *)message)
+{
+  [self.bridge.uiManager addUIBlock:^(__unused RCTUIManager *uiManager, NSDictionary<NSNumber *, RCTWebView *> *viewRegistry) {
+    RCTWebView *view = viewRegistry[reactTag];
+    if (![view isKindOfClass:[RCTWebView class]]) {
+      RCTLogError(@"Invalid view returned from registry, expecting RCTWebView, got: %@", view);
+    } else {
+      [view postMessage:message];
+    }
+  }];
+}
+
 #pragma mark - Exported synchronous methods
 
 - (BOOL)webView:(__unused RCTWebView *)webView

diff --git a/ReactAndroid/src/main/java/com/facebook/react/uimanager/UIManagerModuleConstants.java b/ReactAndroid/src/main/java/com/facebook/react/uimanager/UIManagerModuleConstants.java
@@ -77,6 +77,7 @@
         .put("topLoadingFinish", MapBuilder.of("registrationName", "onLoadingFinish"))
         .put("topLoadingStart", MapBuilder.of("registrationName", "onLoadingStart"))
         .put("topSelectionChange", MapBuilder.of("registrationName", "onSelectionChange"))
+        .put("topMessage", MapBuilder.of("registrationName", "onMessage"))
         .build();
   }
 

diff --git a/ReactAndroid/src/main/java/com/facebook/react/views/webview/BUCK b/ReactAndroid/src/main/java/com/facebook/react/views/webview/BUCK
@@ -4,6 +4,7 @@ android_library(
   name = 'webview',
   srcs = glob(['**/*.java']),
   deps = [
+    react_native_dep('libraries/fbcore/src/main/java/com/facebook/common/logging:logging'),
     react_native_target('java/com/facebook/react/bridge:bridge'),
     react_native_target('java/com/facebook/react/uimanager:uimanager'),
     react_native_target('java/com/facebook/react/uimanager/annotations:annotations'),