fixed onLoadResource, added InAppBrowser.addJavaScriptHandler() and...

fixed onLoadResource, added InAppBrowser.addJavaScriptHandler() and InAppBrowser.removeJavaScriptHandler() methods, v0.3.0

CHANGELOG.md

+## 0.3.0
+
+- fixed WebView.storyboard to deployment target 8.0
+- added `InAppBrowser.onLoadResource()` method. The event fires when the InAppBrowser webview loads a resource
+- added `InAppBrowser.addJavaScriptHandler()` and `InAppBrowser.removeJavaScriptHandler()` methods to add/remove javascript message handlers
+- removed `keyboardDisplayRequiresUserAction` from iOS available options
+- now the `url` parameter of `InAppBrowser.open()` is optional. The default value is `about:blank`
+
 ## 0.2.1
 
-- added InAppBrowser.onConsoleMessage() method to manage console messages
-- fixed InAppBrowser.injectScriptCode() method when there is not a return value
+- added `InAppBrowser.onConsoleMessage()` method to manage console messages
+- fixed `InAppBrowser.injectScriptCode()` method when there is not a return value
 
 ## 0.2.0
 

README.md

@@ -39,6 +39,10 @@ class MyInAppBrowser extends InAppBrowser {
   @override
   Future onLoadStop(String url) async {
     print("\n\nStopped $url\n\n");
+
+    // call a javascript message handler
+    await this.injectScriptCode("window.flutter_inappbrowser.callHandler('handlerNameTest', 1, 5,'string', {'key': 5}, [4,6,8]);");
+
     // print body html
     print(await this.injectScriptCode("document.body.innerHTML"));
 
@@ -78,6 +82,11 @@ class MyInAppBrowser extends InAppBrowser {
     this.loadUrl(url);
   }
 
+  @override
+  void onLoadResource(WebResourceResponse response, WebResourceRequest request) {
+    print("Started at: " + response.startTime.toString() + "ms ---> duration: " + response.duration.toString() + "ms " + response.url);
+  }
+
   @override
   void onConsoleMessage(ConsoleMessage consoleMessage) {
     print("""
@@ -105,6 +114,12 @@ class _MyAppState extends State<MyApp> {
   @override
   void initState() {
     super.initState();
+
+    // listen for post messages coming from the JavaScript side
+    int indexTest = inAppBrowserFallback.addJavaScriptHandler("handlerNameTest", (arguments) async {
+      print("handlerNameTest arguments");
+      print(arguments); // it prints: [1, 5, string, {key: 5}, [4, 6, 8]]
+    });
   }
 
   @override
@@ -117,7 +132,8 @@ class _MyAppState extends State<MyApp> {
         body: new Center(
           child: new RaisedButton(onPressed: () {
             inAppBrowser.open("https://flutter.io/", options: {
-               "useShouldOverrideUrlLoading": true
+               "useShouldOverrideUrlLoading": true,
+               "useOnLoadResource": true
              });
           },
           child: Text("Open InAppBrowser")
@@ -134,12 +150,12 @@ class _MyAppState extends State<MyApp> {
 Opens a URL in a new InAppBrowser instance or the system browser.
 
 ```dart
-inAppBrowser.open(String url, {Map<String, String> headers = const {}, String target = "_self", Map<String, dynamic> options = const {}});
+inAppBrowser.open({String url = "about:blank", Map<String, String> headers = const {}, String target = "_self", Map<String, dynamic> options = const {}});
 ```
 
 Opens an `url` in a new `InAppBrowser` instance or the system browser.
 
-- `url`: The `url` to load. Call `encodeUriComponent()` on this if the `url` contains Unicode characters.
+- `url`: The `url` to load. Call `encodeUriComponent()` on this if the `url` contains Unicode characters. The default value is `about:blank`.
 
 - `headers`: The additional headers to be used in the HTTP request for this URL, specified as a map from name to value.
 
@@ -153,6 +169,7 @@ Opens an `url` in a new `InAppBrowser` instance or the system browser.
 
   All platforms support:
   - __useShouldOverrideUrlLoading__: Set to `true` to be able to listen at the `shouldOverrideUrlLoading` event. The default value is `false`.
+  - __useOnLoadResource__: Set to `true` to be able to listen at the `onLoadResource()` event. The default value is `false`.
   - __clearCache__: Set to `true` to have all the browser's cache cleared before the new window is opened. The default value is `false`.
   - __userAgent___: Set the custom WebView's user-agent.
   - __javaScriptEnabled__: Set to `true` to enable JavaScript. The default value is `true`.
@@ -200,6 +217,7 @@ Example:
 ```dart
 inAppBrowser.open('https://flutter.io/', options: {
   "useShouldOverrideUrlLoading": true,
+  "useOnLoadResource": true,
   "clearCache": true,
   "disallowOverScroll": true,
   "domStorageEnabled": true,
@@ -252,7 +270,8 @@ Event fires when the `InAppBrowser` webview receives a `ConsoleMessage`.
 ```
 
 Give the host application a chance to take control when a URL is about to be loaded in the current WebView.
-In order to be able to listen this event, you need to set `useShouldOverrideUrlLoading` option to `true`.
+
+**NOTE**: In order to be able to listen this event, you need to set `useShouldOverrideUrlLoading` option to `true`.
 ```dart
   @override
   void shouldOverrideUrlLoading(String url) {
@@ -260,6 +279,18 @@ In order to be able to listen this event, you need to set `useShouldOverrideUrlL
   }
 ```
 
+Event fires when the `InAppBrowser` webview loads a resource.
+
+**NOTE**: In order to be able to listen this event, you need to set `useOnLoadResource` option to `true`.
+
+**NOTE only for iOS**: In some cases, the `response.data` of a `response` with `text/html` encoding could be empty.
+```dart
+  @override
+  void onLoadResource(WebResourceResponse response, WebResourceRequest request) {
+
+  }
+```
+
 #### Future\<void\> InAppBrowser.loadUrl
 
 Loads the given `url` with optional `headers` specified as a map from name to value.
@@ -372,6 +403,30 @@ Injects a CSS file into the `InAppBrowser` window. (Only available when the targ
 inAppBrowser.injectStyleFile(String urlFile);
 ```
 
+#### int InAppBrowser.addJavaScriptHandler
+
+Adds/Appends a JavaScript message handler `callback` (`JavaScriptHandlerCallback`) that listen to post messages sent from JavaScript by the handler with name `handlerName`.
+Returns the position `index` of the handler that can be used to remove it with the `removeJavaScriptHandler()` method.
+
+The Android implementation uses [addJavascriptInterface](https://developer.android.com/reference/android/webkit/WebView#addJavascriptInterface(java.lang.Object,%20java.lang.String)).
+The iOS implementation uses [addScriptMessageHandler](https://developer.apple.com/documentation/webkit/wkusercontentcontroller/1537172-addscriptmessagehandler?language=objc)
+
+The JavaScript function that can be used to call the handler is `window.flutter_inappbrowser.callHandler(handlerName <String>, ...args);`, where `args` are [rest parameters](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters).
+The `args` will be stringified automatically using `JSON.stringify(args)` method and then they will be decoded on the Dart side.
+
+```dart
+inAppBrowser.addJavaScriptHandler(String handlerName, JavaScriptHandlerCallback callback);
+```
+
+#### bool InAppBrowser.removeJavaScriptHandler
+
+Removes a JavaScript message handler previously added with the `addJavaScriptHandler()` method in the `handlerName` list by its position `index`.
+Returns `true` if the callback is removed, otherwise `false`.
+```dart
+inAppBrowser.removeJavaScriptHandler(String handlerName, int index);
+```
+
+
 ### `ChromeSafariBrowser` class
 Create a Class that extends the `ChromeSafariBrowser` Class in order to override the callbacks to manage the browser events. Example:
 ```dart

android/src/main/java/com/pichillilorenzo/flutter_inappbrowser/InAppBrowserOptions.java

@@ -5,6 +5,7 @@ public class InAppBrowserOptions extends Options {
     final static String LOG_TAG = "InAppBrowserOptions";
 
     public boolean useShouldOverrideUrlLoading = false;
+    public boolean useOnLoadResource = false;
     public boolean clearCache = false;
     public String userAgent = "";
     public boolean javaScriptEnabled = true;

android/src/main/java/com/pichillilorenzo/flutter_inappbrowser/InAppBrowserWebViewClient.java

@@ -31,6 +31,7 @@ public class InAppBrowserWebViewClient extends WebViewClient {
     protected static final String LOG_TAG = "IABWebViewClient";
     private WebViewActivity activity;
     Map<Integer, String> statusCodeMapping = new HashMap<Integer, String>();
+    long startPageTime = 0;
 
     public InAppBrowserWebViewClient(WebViewActivity activity) {
         super();
@@ -164,6 +165,8 @@ public class InAppBrowserWebViewClient extends WebViewClient {
     public void onPageStarted(WebView view, String url, Bitmap favicon) {
         super.onPageStarted(view, url, favicon);
 
+        startPageTime = System.currentTimeMillis();
+
         activity.isLoading = true;
 
         if (activity.searchView != null && !url.equals(activity.searchView.getQuery().toString())) {
@@ -195,7 +198,8 @@ public class InAppBrowserWebViewClient extends WebViewClient {
         view.requestFocus();
 
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
-            view.evaluateJavascript(activity.jsConsoleLogScript, null);
+            view.evaluateJavascript(WebViewActivity.consoleLogJS, null);
+            view.evaluateJavascript(JavaScriptBridgeInterface.flutterInAppBroserJSClass, null);
         }
 
         Map<String, Object> obj = new HashMap<>();
@@ -264,14 +268,24 @@ public class InAppBrowserWebViewClient extends WebViewClient {
     @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
     @Override
     public WebResourceResponse shouldInterceptRequest (WebView view, WebResourceRequest request){
+
+        if (!request.getMethod().toLowerCase().equals("get") || !activity.options.useOnLoadResource) {
+            return null;
+        }
+
         final String url = request.getUrl().toString();
 
+        try {
             Request mRequest = new Request.Builder().url(url).build();
 
-        try {
-            long loadingTime = System.currentTimeMillis();
+            long startResourceTime = System.currentTimeMillis();
             Response response = activity.httpClient.newCall(mRequest).execute();
-            loadingTime = System.currentTimeMillis() - loadingTime;
+            long startTime = startResourceTime - startPageTime;
+            long duration = System.currentTimeMillis() - startResourceTime;
+
+            if (response.cacheResponse() != null) {
+                duration = 0;
+            }
 
             String reasonPhrase = response.message();
             if (reasonPhrase.equals("")) {
@@ -281,20 +295,20 @@ public class InAppBrowserWebViewClient extends WebViewClient {
 
             Map<String, String> headersResponse = new HashMap<String, String>();
             for (Map.Entry<String, List<String>> entry : response.headers().toMultimap().entrySet()) {
-                String value = "";
+                StringBuilder value = new StringBuilder();
                 for (String val: entry.getValue()) {
-                    value += (value == "") ? val : "; " + val;
+                    value.append( (value.toString().isEmpty()) ? val : "; " + val );
                 }
-                headersResponse.put(entry.getKey().toLowerCase(), value);
+                headersResponse.put(entry.getKey().toLowerCase(), value.toString());
             }
 
             Map<String, String> headersRequest = new HashMap<String, String>();
             for (Map.Entry<String, List<String>> entry : mRequest.headers().toMultimap().entrySet()) {
-                String value = "";
+                StringBuilder value = new StringBuilder();
                 for (String val: entry.getValue()) {
-                    value += (value == "") ? val : "; " + val;
+                    value.append( (value.toString().isEmpty()) ? val : "; " + val );
                 }
-                headersRequest.put(entry.getKey().toLowerCase(), value);
+                headersRequest.put(entry.getKey().toLowerCase(), value.toString());
             }
 
             Map<String, Object> obj = new HashMap<>();
@@ -309,7 +323,8 @@ public class InAppBrowserWebViewClient extends WebViewClient {
             res.put("url", url);
             res.put("statusCode", response.code());
             res.put("headers", headersResponse);
-            res.put("loadingTime", loadingTime);
+            res.put("startTime", startTime);
+            res.put("duration", duration);
             res.put("data", dataBytes);
 
             req.put("url", url);
@@ -332,7 +347,11 @@ public class InAppBrowserWebViewClient extends WebViewClient {
         } catch (IOException e) {
             e.printStackTrace();
             Log.d(LOG_TAG, e.getMessage());
+        } catch (Exception e) {
+            e.printStackTrace();
+            Log.d(LOG_TAG, e.getMessage());
         }
+
         return null;
     }
 

android/src/main/java/com/pichillilorenzo/flutter_inappbrowser/JavaScriptBridgeInterface.java

+package com.pichillilorenzo.flutter_inappbrowser;
+
+import android.webkit.JavascriptInterface;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class JavaScriptBridgeInterface {
+  private static final String LOG_TAG = "JSBridgeInterface";
+  static final String name = "flutter_inappbrowser";
+  WebViewActivity activity;
+
+  static final String flutterInAppBroserJSClass = "window." + name + ".callHandler = function(handlerName, ...args) {\n" +
+    "window." + name + "._callHandler(handlerName, JSON.stringify(args));\n" +
+  "}\n";
+
+  JavaScriptBridgeInterface(WebViewActivity a) {
+    activity = a;
+  }
+
+  @JavascriptInterface
+  public void _callHandler(String handlerName, String args) {
+    Map<String, Object> obj = new HashMap<>();
+    obj.put("uuid", activity.uuid);
+    obj.put("handlerName", handlerName);
+    obj.put("args", args);
+    InAppBrowserFlutterPlugin.channel.invokeMethod("onCallJsHandler", obj);
+  }
+}

android/src/main/java/com/pichillilorenzo/flutter_inappbrowser/WebViewActivity.java

@@ -23,6 +23,7 @@ import java.util.HashMap;
 import java.util.Map;
 
 import io.flutter.plugin.common.MethodChannel;
+import okhttp3.Cache;
 import okhttp3.OkHttpClient;
 
 public class WebViewActivity extends AppCompatActivity {
@@ -40,7 +41,7 @@ public class WebViewActivity extends AppCompatActivity {
     public boolean isHidden = false;
     OkHttpClient httpClient;
 
-    static final String jsConsoleLogScript = "(function() {\n"+
+    static final String consoleLogJS = "(function() {\n"+
 "   var oldLogs = {\n"+
 "       'log': console.log,\n"+
 "       'debug': console.debug,\n"+
@@ -89,14 +90,18 @@ public class WebViewActivity extends AppCompatActivity {
 
         prepareWebView();
 
-        httpClient = new OkHttpClient();
+        int cacheSize = 10 * 1024 * 1024; // 10MB
+        httpClient = new OkHttpClient().newBuilder().cache(new Cache(getApplicationContext().getCacheDir(), cacheSize)).build();
 
         webView.loadUrl(url, headers);
+        //webView.loadData("<!DOCTYPE html> <html lang=\"en\"> <head> <meta charset=\"UTF-8\"> <title>Document</title> </head> <body> ciao <img src=\"https://via.placeholder.com/350x150\" /> <img src=\"./images/test\" alt=\"not found\" /></body> </html>", "text/html", "utf8");
 
     }
 
     private void prepareWebView() {
 
+        webView.addJavascriptInterface(new JavaScriptBridgeInterface(this), JavaScriptBridgeInterface.name);
+
         inAppBrowserWebChromeClient = new InAppBrowserWebChromeClient(this);
         webView.setWebChromeClient(inAppBrowserWebChromeClient);
 

example/lib/main.dart

@@ -13,8 +13,9 @@ class MyInAppBrowser extends InAppBrowser {
   Future onLoadStop(String url) async {
     print("\n\nStopped $url\n\n");
 
-//    // javascript error
-//    await this.injectScriptCode("console.log({'testJavaScriptError': 5}));");
+    await this.injectScriptCode("window.flutter_inappbrowser.callHandler('handlerTest', 1, 5,'string', {'key': 5}, [4,6,8]);");
+    await this.injectScriptCode("window.flutter_inappbrowser.callHandler('handlerTest2', false, null, undefined);");
+    await this.injectScriptCode("setTimeout(function(){window.flutter_inappbrowser.callHandler('handlerTest', 'anotherString');}, 1000);");
 //
 //    await this.injectScriptCode("console.log({'testObject': 5});");
 //    await this.injectScriptCode("console.warn('testWarn',null);");
@@ -73,20 +74,21 @@ class MyInAppBrowser extends InAppBrowser {
 
   @override
   void onLoadResource(WebResourceResponse response, WebResourceRequest request) {
-    print(response.loadingTime.toString() + "ms " + response.url);
-    if (response.headers["content-length"] != null)
-      print(response.headers["content-length"] + " length");
+
+    print("Started at: " + response.startTime.toString() + "ms ---> duration: " + response.duration.toString() + "ms " + response.url);
+//    if (response.headers["content-length"] != null)
+//      print(response.headers["content-length"] + " length");
   }
 
   @override
   void onConsoleMessage(ConsoleMessage consoleMessage) {
-    print("""
-    console output: 
-      sourceURL: ${consoleMessage.sourceURL}
-      lineNumber: ${consoleMessage.lineNumber}
-      message: ${consoleMessage.message}
-      messageLevel: ${consoleMessage.messageLevel}
-    """);
+//    print("""
+//    console output:
+//      sourceURL: ${consoleMessage.sourceURL}
+//      lineNumber: ${consoleMessage.lineNumber}
+//      message: ${consoleMessage.message}
+//      messageLevel: ${consoleMessage.messageLevel}
+//    """);
   }
 }
 
@@ -112,9 +114,12 @@ class MyChromeSafariBrowser extends ChromeSafariBrowser {
   }
 }
 
+// adding a webview fallback
 MyChromeSafariBrowser chromeSafariBrowser = new MyChromeSafariBrowser(inAppBrowserFallback);
 
-void main() => runApp(new MyApp());
+void main() {
+  runApp(new MyApp());
+}
 
 class MyApp extends StatefulWidget {
   @override
@@ -126,6 +131,15 @@ class _MyAppState extends State<MyApp> {
   @override
   void initState() {
     super.initState();
+    int indexTest = inAppBrowserFallback.addJavaScriptHandler("handlerTest", (arguments) async {
+      print("handlerTest arguments");
+      print(arguments);
+    });
+    int indexTest2 = inAppBrowserFallback.addJavaScriptHandler("test2", (arguments) async {
+      print("handlerTest2 arguments");
+      print(arguments);
+      inAppBrowserFallback.removeJavaScriptHandler("test", indexTest);
+    });
   }
 
   @override
@@ -139,6 +153,7 @@ class _MyAppState extends State<MyApp> {
           child: new RaisedButton(onPressed: () {
             //chromeSafariBrowser.open("https://flutter.io/");
             inAppBrowserFallback.open(url: "https://flutter.io/", options: {
+              //"useOnLoadResource": true,
               //"hidden": true,
               //"toolbarTopFixedTitle": "Fixed title",
               //"useShouldOverrideUrlLoading": true

ios/Classes/InAppBrowserOptions.swift

@@ -11,6 +11,7 @@ import Foundation
 public class InAppBrowserOptions: Options {
     
     var useShouldOverrideUrlLoading = false
+    var useOnLoadResource = false
     var clearCache = false
     var userAgent = ""
     var javaScriptEnabled = true

ios/Classes/MyURLProtocol.swift

-//
-//  MyURLProtocol.swift
-//  Pods
-//
-//  Created by Lorenzo on 12/10/18.
-//
-
-import Foundation
-import WebKit
-
-
-func currentTimeInMilliSeconds() -> Int {
-    let currentDate = Date()
-    let since1970 = currentDate.timeIntervalSince1970
-    return Int(since1970 * 1000)
-}
-
-class MyURLProtocol: URLProtocol {
-    
-//    struct Constants {
-//        static let RequestHandledKey = "URLProtocolRequestHandled"
-//    }
-    
-    var wkWebViewUuid: String?
-    var session: URLSession?
-    var sessionTask: URLSessionDataTask?
-    var response: URLResponse?
-    var data: Data?
-    static var wkWebViewDelegateMap: [String: MyURLProtocolDelegate] = [:]
-    var loadingTime: Int = 0
-    
-    override init(request: URLRequest, cachedResponse: CachedURLResponse?, client: URLProtocolClient?) {
-        super.init(request: request, cachedResponse: cachedResponse, client: client)
-        
-        self.wkWebViewUuid = MyURLProtocol.getUuid(request)
-        
-        if session == nil && self.wkWebViewUuid != nil {
-            session = URLSession(configuration: .default, delegate: self, delegateQueue: nil)
-        }
-    }
-    
-    override class func canInit(with request: URLRequest) -> Bool {
-
-        if getUuid(request) == nil {
-            return false
-        }
-//        if MyURLProtocol.property(forKey: Constants.RequestHandledKey, in: request) != nil {
-//            return false
-//        }
-        return true
-    }
-    
-    override class func canonicalRequest(for request: URLRequest) -> URLRequest {
-        return request
-    }
-    
-    override func startLoading() {
-        let newRequest = ((request as NSURLRequest).mutableCopy() as? NSMutableURLRequest)!
-        loadingTime = currentTimeInMilliSeconds()
-        //MyURLProtocol.setProperty(true, forKey: Constants.RequestHandledKey, in: newRequest)
-        sessionTask = session?.dataTask(with: newRequest as URLRequest)
-        sessionTask?.resume()
-    }
-    
-    override func stopLoading() {
-        if let uuid = self.wkWebViewUuid {
-            if MyURLProtocol.wkWebViewDelegateMap[uuid] != nil && self.response != nil {
-                loadingTime = currentTimeInMilliSeconds() - loadingTime
-                if self.data == nil {
-                    self.data = Data()
-                }
-                MyURLProtocol.wkWebViewDelegateMap[uuid]!.didReceiveResponse(self.response!, fromRequest: request, withData: self.data!, loadingTime: loadingTime)
-            }
-        }
-        
-        sessionTask?.cancel()
-    }
-    
-    class func getUuid(_ request: URLRequest?) -> String? {
-        let userAgent: String? = request?.allHTTPHeaderFields?["User-Agent"]
-        var uuid: String? = nil
-        if userAgent != nil {
-            if userAgent!.contains("WKWebView/") {
-                let userAgentSplitted = userAgent!.split(separator: " ")
-                uuid = String(userAgentSplitted[userAgentSplitted.count-1]).replacingOccurrences(of: "WKWebView/", with: "")
-            }
-        }
-        return uuid
-    }
-}
-
-extension MyURLProtocol: URLSessionDataDelegate {
-    func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) {
-        if self.data == nil {
-            self.data = data
-        }
-        else {
-            self.data!.append(data)
-        }
-        client?.urlProtocol(self, didLoad: data)
-    }
-    
-    func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive response: URLResponse, completionHandler: @escaping (URLSession.ResponseDisposition) -> Void) {
-        let policy = URLCache.StoragePolicy(rawValue: request.cachePolicy.rawValue) ?? .notAllowed
-        self.response = response
-        client?.urlProtocol(self, didReceive: response, cacheStoragePolicy: policy)
-        completionHandler(.allow)
-    }
-    
-    func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
-        if let error = error {
-            client?.urlProtocol(self, didFailWithError: error)
-        } else {
-            client?.urlProtocolDidFinishLoading(self)
-        }
-    }
-    
-    func urlSession(_ session: URLSession, task: URLSessionTask, willPerformHTTPRedirection response: HTTPURLResponse, newRequest request: URLRequest, completionHandler: @escaping (URLRequest?) -> Void) {
-        client?.urlProtocol(self, wasRedirectedTo: request, redirectResponse: response)
-        completionHandler(request)
-    }
-    
-    func urlSession(_ session: URLSession, didBecomeInvalidWithError error: Error?) {
-        guard let error = error else { return }
-        client?.urlProtocol(self, didFailWithError: error)
-    }
-    
-    func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
-        let protectionSpace = challenge.protectionSpace
-        let sender = challenge.sender
-        
-        if protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust {
-            if let serverTrust = protectionSpace.serverTrust {
-                let credential = URLCredential(trust: serverTrust)
-                sender?.use(credential, for: challenge)
-                completionHandler(.useCredential, credential)
-                return
-            }
-        }
-    }
-    
-    func urlSessionDidFinishEvents(forBackgroundURLSession session: URLSession) {
-        client?.urlProtocolDidFinishLoading(self)
-    }
-}
-
-protocol MyURLProtocolDelegate {
-    func didReceiveResponse(_ response: URLResponse, fromRequest request: URLRequest?, withData data: Data, loadingTime time: Int)
-}

ios/Classes/NSURLProtocol+WKWebVIew.h

-//
-//  NSURLProtocol+WKWebVIew.h
-//  Pods
-//
-//  Created by Lorenzo on 11/10/18.
-//
-
-#ifndef NSURLProtocol_WKWebVIew_h
-#define NSURLProtocol_WKWebVIew_h
-
-
-#endif /* NSURLProtocol_WKWebVIew_h */
-
-#import <Foundation/Foundation.h>
-
-@interface NSURLProtocol (WKWebVIew)
-
-+ (void)wk_registerScheme:(NSString*)scheme;
-
-+ (void)wk_unregisterScheme:(NSString*)scheme;
-
-
-@end

ios/Classes/NSURLProtocol+WKWebVIew.m

-//
-//  NSURLProtocol+WKWebVIew.m
-//  Pods
-//
-//  Created by Lorenzo on 11/10/18.
-//
-
-#import <Foundation/Foundation.h>
-#import "NSURLProtocol+WKWebVIew.h"
-#import <WebKit/WebKit.h>
-//FOUNDATION_STATIC_INLINE 属于属于runtime范畴，你的.m文件需要频繁调用一个函数,可以用static inline来声明。从SDWebImage从get到的。
-FOUNDATION_STATIC_INLINE Class ContextControllerClass() {
-    static Class cls;
-    if (!cls) {
-        cls = [[[WKWebView new] valueForKey:@"browsingContextController"] class];
-    }
-    return cls;
-}
-
-FOUNDATION_STATIC_INLINE SEL RegisterSchemeSelector() {
-    return NSSelectorFromString(@"registerSchemeForCustomProtocol:");
-}
-
-FOUNDATION_STATIC_INLINE SEL UnregisterSchemeSelector() {
-    return NSSelectorFromString(@"unregisterSchemeForCustomProtocol:");
-}
-
-@implementation NSURLProtocol (WebKitSupport)
-
-+ (void)wk_registerScheme:(NSString *)scheme {
-    Class cls = ContextControllerClass();
-    SEL sel = RegisterSchemeSelector();
-    if ([(id)cls respondsToSelector:sel]) {
-        // 放弃编辑器警告
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Warc-performSelector-leaks"
-        [(id)cls performSelector:sel withObject:scheme];
-#pragma clang diagnostic pop
-    }
-}
-
-+ (void)wk_unregisterScheme:(NSString *)scheme {
-    Class cls = ContextControllerClass();
-    SEL sel = UnregisterSchemeSelector();
-    if ([(id)cls respondsToSelector:sel]) {
-        // 放弃编辑器警告
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Warc-performSelector-leaks"
-        [(id)cls performSelector:sel withObject:scheme];
-#pragma clang diagnostic pop
-    }
-}
-
-@end

ios/Classes/SwiftFlutterPlugin.swift

@@ -22,6 +22,19 @@ import Foundation
 import AVFoundation
 import SafariServices
 
+//class CustomURLCache: URLCache {
+//    override func cachedResponse(for request: URLRequest) -> CachedURLResponse? {
+//        dump(request.url)
+//        return super.cachedResponse(for: request)
+//    }
+//
+//    override func getCachedResponse(for dataTask: URLSessionDataTask,
+//                                    completionHandler: @escaping (CachedURLResponse?) -> Void) {
+//        dump(dataTask.response)
+//        super.getCachedResponse(for: dataTask, completionHandler: completionHandler)
+//    }
+//}
+
 let WEBVIEW_STORYBOARD = "WebView"
 let WEBVIEW_STORYBOARD_CONTROLLER_ID = "viewController"
 
@@ -46,9 +59,12 @@ public class SwiftFlutterPlugin: NSObject, FlutterPlugin {
     }
     
     public static func register(with registrar: FlutterPluginRegistrar) {
-        URLProtocol.wk_registerScheme("http")
-        URLProtocol.wk_registerScheme("https")
-        URLProtocol.registerClass(MyURLProtocol.self)
+//        URLProtocol.wk_registerScheme("http")
+//        URLProtocol.wk_registerScheme("https")
+//        URLProtocol.registerClass(MyURLProtocol.self)
+
+        //URLCache.shared = CustomURLCache()
+        
         let channel = FlutterMethodChannel(name: "com.pichillilorenzo/flutter_inappbrowser", binaryMessenger: registrar.messenger())
         let instance = SwiftFlutterPlugin(with: registrar)
         registrar.addMethodCallDelegate(instance, channel: channel)
@@ -423,7 +439,8 @@ public class SwiftFlutterPlugin: NSObject, FlutterPlugin {
                     
                     if error != nil {
                         let userInfo = (error! as NSError).userInfo
-                        self.onConsoleMessage(uuid: uuid, sourceURL: (userInfo["WKJavaScriptExceptionSourceURL"] as! URL).absoluteString, lineNumber: userInfo["WKJavaScriptExceptionLineNumber"] as! Int, message: userInfo["WKJavaScriptExceptionMessage"] as! String, messageLevel: "ERROR")
+                        dump(userInfo)
+                        self.onConsoleMessage(uuid: uuid, sourceURL: (userInfo["WKJavaScriptExceptionSourceURL"] as? URL)?.absoluteString ?? "", lineNumber: userInfo["WKJavaScriptExceptionLineNumber"] as! Int, message: userInfo["WKJavaScriptExceptionMessage"] as! String, messageLevel: "ERROR")
                     }
                     
                     if value == nil {
@@ -492,7 +509,7 @@ public class SwiftFlutterPlugin: NSObject, FlutterPlugin {
         }
     }
     
-    func onLoadResource(uuid: String, webView: WKWebView, response: URLResponse, fromRequest request: URLRequest?, withData data: Data, loadingTime time: Int) {
+    func onLoadResource(uuid: String, webView: WKWebView, response: URLResponse, fromRequest request: URLRequest?, withData data: Data, startTime: Int, duration: Int) {
         if self.webViewControllers[uuid] != nil {
             var headersResponse = (response as! HTTPURLResponse).allHeaderFields as! [String: String]
             headersResponse.lowercaseKeys()
@@ -506,7 +523,8 @@ public class SwiftFlutterPlugin: NSObject, FlutterPlugin {
                     "url": response.url!.absoluteString,
                     "statusCode": (response as! HTTPURLResponse).statusCode,
                     "headers": headersResponse,
-                    "loadingTime": time,
+                    "startTime": startTime,
+                    "duration": duration,
                     "data": data
                 ],
                 "request": [
@@ -551,6 +569,10 @@ public class SwiftFlutterPlugin: NSObject, FlutterPlugin {
         channel.invokeMethod("onChromeSafariBrowserClosed", arguments: ["uuid": uuid])
     }
     
+    func onCallJsHandler(uuid: String, webView: WKWebView, handlerName: String, args: String) {
+        channel.invokeMethod("onCallJsHandler", arguments: ["uuid": uuid, "handlerName": handlerName, "args": args])
+    }
+    
     func safariExit(uuid: String) {
         if let safariViewController = self.safariViewControllers[uuid] {
             if #available(iOS 9.0, *) {

lib/flutter_inappbrowser.dart

@@ -22,11 +22,13 @@
 import 'dart:async';
 import 'dart:collection';
 import 'dart:typed_data';
+import 'dart:convert';
 
 import 'package:flutter/services.dart';
 import 'package:uuid/uuid.dart';
 
 typedef Future<dynamic> ListenerCallback(MethodCall call);
+typedef Future<void> JavaScriptHandlerCallback(List<dynamic> arguments);
 
 var _uuidGenerator = new Uuid();
 
@@ -35,6 +37,8 @@ enum ConsoleMessageLevel {
   DEBUG, ERROR, LOG, TIP, WARNING
 }
 
+///Public class representing a resource request of the [InAppBrowser] WebView.
+///It is used by the method [InAppBrowser.onLoadResource()].
 class WebResourceRequest {
 
   String url;
@@ -45,15 +49,18 @@ class WebResourceRequest {
 
 }
 
+///Public class representing a resource response of the [InAppBrowser] WebView.
+///It is used by the method [InAppBrowser.onLoadResource()].
 class WebResourceResponse {
 
   String url;
   Map<String, String> headers;
   int statusCode;
-  int loadingTime;
+  int startTime;
+  int duration;
   Uint8List data;
 
-  WebResourceResponse(this.url, this.headers, this.statusCode, this.loadingTime, this.data);
+  WebResourceResponse(this.url, this.headers, this.statusCode, this.startTime, this.duration, this.data);
 
 }
 
@@ -99,6 +106,7 @@ class _ChannelManager {
 class InAppBrowser {
 
   String uuid;
+  Map<String, List<JavaScriptHandlerCallback>> javaScriptHandlersMap = HashMap<String, List<JavaScriptHandlerCallback>>();
 
   ///
   InAppBrowser () {
@@ -139,7 +147,8 @@ class InAppBrowser {
         Map<dynamic, dynamic> headersResponse = rawResponse["headers"];
         headersResponse = headersResponse.cast<String, String>();
         int statusCode = rawResponse["statusCode"];
-        int loadingTime = rawResponse["loadingTime"];
+        int startTime = rawResponse["startTime"];
+        int duration = rawResponse["duration"];
         Uint8List data = rawResponse["data"];
 
         String urlRequest = rawRequest["url"];
@@ -147,7 +156,7 @@ class InAppBrowser {
         headersRequest = headersResponse.cast<String, String>();
         String method = rawRequest["method"];
 
-        var response = new WebResourceResponse(urlResponse, headersResponse, statusCode, loadingTime, data);
+        var response = new WebResourceResponse(urlResponse, headersResponse, statusCode, startTime, duration, data);
         var request = new WebResourceRequest(urlRequest, headersRequest, method);
 
         onLoadResource(response, request);
@@ -165,13 +174,22 @@ class InAppBrowser {
         });
         onConsoleMessage(ConsoleMessage(sourceURL, lineNumber, message, messageLevel));
         break;
+      case "onCallJsHandler":
+        String handlerName = call.arguments["handlerName"];
+        List<dynamic> args = jsonDecode(call.arguments["args"]);
+        if (javaScriptHandlersMap.containsKey(handlerName)) {
+          for (var handler in javaScriptHandlersMap[handlerName]) {
+            handler(args);
+          }
+        }
+        break;
     }
     return new Future.value("");
   }
 
   ///Opens an [url] in a new [InAppBrowser] instance or the system browser.
   ///
-  ///- [url]: The [url] to load. Call [encodeUriComponent()] on this if the [url] contains Unicode characters.
+  ///- [url]: The [url] to load. Call [encodeUriComponent()] on this if the [url] contains Unicode characters. The default value is `about:blank`.
   ///
   ///- [headers]: The additional headers to be used in the HTTP request for this URL, specified as a map from name to value.
   ///
@@ -185,6 +203,7 @@ class InAppBrowser {
   ///
   ///  All platforms support:
   ///  - __useShouldOverrideUrlLoading__: Set to `true` to be able to listen at the [shouldOverrideUrlLoading()] event. The default value is `false`.
+  ///  - __useOnLoadResource__: Set to `true` to be able to listen at the [onLoadResource()] event. The default value is `false`.
   ///  - __clearCache__: Set to `true` to have all the browser's cache cleared before the new window is opened. The default value is `false`.
   ///  - __userAgent___: Set the custom WebView's user-agent.
   ///  - __javaScriptEnabled__: Set to `true` to enable JavaScript. The default value is `true`.
@@ -342,6 +361,33 @@ class InAppBrowser {
     return await _ChannelManager.channel.invokeMethod('injectStyleFile', args);
   }
 
+  ///Adds/Appends a JavaScript message handler [callback] ([JavaScriptHandlerCallback]) that listen to post messages sent from JavaScript by the handler with name [handlerName].
+  ///Returns the position `index` of the handler that can be used to remove it with the [removeJavaScriptHandler()] method.
+  ///
+  ///The Android implementation uses [addJavascriptInterface](https://developer.android.com/reference/android/webkit/WebView#addJavascriptInterface(java.lang.Object,%20java.lang.String)).
+  ///The iOS implementation uses [addScriptMessageHandler](https://developer.apple.com/documentation/webkit/wkusercontentcontroller/1537172-addscriptmessagehandler?language=objc)
+  ///
+  ///The JavaScript function that can be used to call the handler is `window.flutter_inappbrowser.callHandler(handlerName <String>, ...args);`, where `args` are [rest parameters](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters).
+  ///The `args` will be stringified automatically using `JSON.stringify(args)` method and then they will be decoded on the Dart side.
+  int addJavaScriptHandler(String handlerName, JavaScriptHandlerCallback callback) {
+    this.javaScriptHandlersMap.putIfAbsent(handlerName, () => List<JavaScriptHandlerCallback>());
+    this.javaScriptHandlersMap[handlerName].add(callback);
+    return this.javaScriptHandlersMap[handlerName].indexOf(callback);
+  }
+
+  ///Removes a JavaScript message handler previously added with the [addJavaScriptHandler()] method in the [handlerName] list by its position [index].
+  ///Returns `true` if the callback is removed, otherwise `false`.
+  bool removeJavaScriptHandler(String handlerName, int index) {
+    try {
+      this.javaScriptHandlersMap[handlerName].removeAt(index);
+      return true;
+    }
+    on RangeError catch(e) {
+      print(e);
+    }
+    return false;
+  }
+
   ///Event fires when the [InAppBrowser] starts to load an [url].
   void onLoadStart(String url) {
 
@@ -363,12 +409,14 @@ class InAppBrowser {
   }
 
   ///Give the host application a chance to take control when a URL is about to be loaded in the current WebView.
-  ///In order to be able to listen this event, you need to set `useShouldOverrideUrlLoading` option to `true`.
+  ///**NOTE**: In order to be able to listen this event, you need to set `useShouldOverrideUrlLoading` option to `true`.
   void shouldOverrideUrlLoading(String url) {
 
   }
 
-  ///Event fires when the [InAppBrowser] webview will load the resource specified by the given [WebResourceRequest].
+  ///Event fires when the [InAppBrowser] webview loads a resource.
+  ///**NOTE**: In order to be able to listen this event, you need to set `useOnLoadResource` option to `true`.
+  ///**NOTE only for iOS**: In some cases, the [response.data] of a [response] with `text/html` encoding could be empty.
   void onLoadResource(WebResourceResponse response, WebResourceRequest request) {
 
   }