Android拦截并获取WebView内部POST请求参数

起因:

有些时候自家APP中嵌入的H5页面并不是自家的。但是很多时候又想在H5不知情的情况下获取H5内部请求的参数,这应该怎么做到呢?

带着这个疑问,就有了这篇博客。

实现过程:

方案一:

最开始想到的方案是直接拦截H5中所有的请求:

 1 webView.setWebViewClient(new WebViewClient() {
 2     @Override
 3     public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceRequest request) {
 4         try {
 5             URL url = new URL(request.getUrl());
 6         } catch (MalformedURLException e) {
 7             e.printStackTrace();
 8         }
 9         Log.e("InternetActivity", request + "");
10         return super.shouldInterceptRequest(view, request);
11     }
12 
13 });

但是通过此方法只能获取get请求的参数(因为参数直接拼在了url链接中),对于post请求的参数无可奈何。

方案二:

后来参考了request_data_webviewclient,有了新的实现方式,具体原理为:给H5注入一段js代码,目的是在每次Ajax请求都会调用Android原生的方法,将请求参数传给客户端。

具体流程如下:

 

其中,

js注入代码:

 1 <script language="JavaScript">
 2 
 3     function generateRandom() {
 4       return Math.floor((1 + Math.random()) * 0x10000)
 5         .toString(16)
 6         .substring(1);
 7     }
 8 
 9 
10     // This only works if `open` and `send` are called in a synchronous way
11     // That is, after calling `open`, there must be no other call to `open` or
12     // `send` from another place of the code until the matching `send` is called.
13     requestID = null;
14     XMLHttpRequest.prototype.reallyOpen = XMLHttpRequest.prototype.open;
15     XMLHttpRequest.prototype.open = function(method, url, async, user, password) {
16         requestID = generateRandom()
17         var signed_url = url + "AJAXINTERCEPT" + requestID;
18         this.reallyOpen(method, signed_url , async, user, password);
19     };
20     XMLHttpRequest.prototype.reallySend = XMLHttpRequest.prototype.send;
21     XMLHttpRequest.prototype.send = function(body) {
22         interception.customAjax(requestID, body);
23         this.reallySend(body);
24     };
25 
26 </script>

客户端拦截请求:

 1 @Override
 2 public final WebResourceResponse shouldInterceptRequest(final WebView view, WebResourceRequest request) {
 3     String requestBody = null;
 4     Uri uri = request.getUrl();
 5 
 6     // 判断是否为Ajax请求(只要链接中包含AJAXINTERCEPT即是)
 7     if (isAjaxRequest(request)) {
 8         // 获取post请求参数
 9         requestBody = getRequestBody(request);
10         // 获取原链接
11         uri = getOriginalRequestUri(request, MARKER);
12     }
13 
14     // 重新构造请求,并获取response
15     WebResourceResponse webResourceResponse = shouldInterceptRequest(view, new WriteHandlingWebResourceRequest(request, requestBody, uri));
16     if (webResourceResponse == null) {
17         return webResourceResponse;
18     } else {
19         return injectIntercept(webResourceResponse, view.getContext());
20     }
21 }

客户端注入js代码:

 1 private WebResourceResponse injectIntercept(WebResourceResponse response, Context context) {
 2     String encoding = response.getEncoding();
 3     String mime = response.getMimeType();
 4 
 5     // WebResourceResponse的mime必须为"text/html",不能是"text/html; charset=utf-8"
 6     if (mime.contains("text/html")) {
 7         mime = "text/html";
 8     }
 9 
10     InputStream responseData = response.getData();
11     InputStream injectedResponseData = injectInterceptToStream(
12             context,
13             responseData,
14             mime,
15             encoding
16     );
17     return new WebResourceResponse(mime, encoding, injectedResponseData);
18 }

注:根据谷歌官方文档,mime必须为"text/html"。

反思:

GitHub地址:webview_post_data

 

大家如果有什么疑问或者建议可以通过评论或者邮件的方式联系我,欢迎大家的评论~

Android拦截并获取WebView内部POST请求参数

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