How to intercept and modify network requests in WebView?

Network request interception in WebView can be implemented in the following ways:

1. Android implementation:

   shouldInterceptRequest method:

   java
   webView.setWebViewClient(new WebViewClient() {
       @Override
       public WebResourceResponse shouldInterceptRequest(WebView view, String url) {
           // Intercept request, return custom response
           return new WebResourceResponse("text/html", "utf-8", inputStream);
       }
       
       @Override
       public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceRequest request) {
           // More detailed request information
           String url = request.getUrl().toString();
           String method = request.getMethod();
           Map<String, String> headers = request.getRequestHeaders();
           // Process request...
       }
   });

2. iOS implementation:

   WKNavigationDelegate:

   swift
   func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
       // Intercept navigation request
       if let url = navigationAction.request.url {
           // Process URL...
       }
       decisionHandler(.allow)
   }

   URLProtocol (deprecated):

   • Can intercept all network requests
   • Need to register custom URLProtocol
   • Note: WKWebView does not support URLProtocol

3. Application scenarios:

   • Resource replacement: Replace local resources, reduce network requests
   • Request modification: Modify request headers, request parameters
   • Response modification: Modify response content
   • Cache control: Implement custom caching strategies
   • Security filtering: Intercept malicious requests
   • Data statistics: Count network requests
   • Mock data: Use mock data during development

4. Points to note:

   • Performance impact: Interception increases request processing time
   • Memory management: Release resources in time
   • Thread safety: Process requests on correct thread
   • Error handling: Properly handle exceptions
   • HTTPS certificates: Handle self-signed certificates and other issues

5. Advanced usage:

   • Use OkHttp interceptor (Android)
   • Implement request retry mechanism
   • Implement request priority control
   • Implement request deduplication
   • Implement request rate limiting