CefSharp过滤图片RequestHandler问题

May ·
更新时间:2024-11-10
· 1642 次阅读

目录

C# CefSharp 过滤 RequestHandler 图片

1、方式一

2、方式二

总结

C# CefSharp 过滤 RequestHandler 图片 1、方式一

ChromiumWebBrowser 实现 IRequestHandler

具体内同参照 附录;将 OnBeforeResourceLoad方法替换成2中的内容,很简单;

2、方式二

继承集成默认的抽象类 DefaultRequestHandler

 internal class RequestHandler : DefaultRequestHandler      {         public  override CefReturnValue  OnBeforeResourceLoad(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IRequestCallback callback)         {             if (request.ResourceType == ResourceType.Image)                 return CefReturnValue.Cancel;             return CefReturnValue.Continue;         } }

对比实现接口方式和继承集成默认的抽象类,发现抽象类可以只实现相关的处理方法更加灵活。而若采用IRequestHandler需要实现RequestHandler接口中的所有方法,否则抛出未实现异常;

和其他网上从Response环节过滤资源图片的方法不同,这里谈到的方法在请求图片资源之前,可以节省流量,加快页面访问速度等。

附录:

using System; using CefSharp.Example.Filters; using System.Security.Cryptography.X509Certificates; using System.Collections.Generic; using System.Text; using CefSharp.Handler; namespace CefSharp.Example.Handlers { /// <summary> /// DefaultRequestHandler provides a base class for you to inherit from /// you only need to implement the methods that are relevant to you. /// If you implement the IRequestHandler interface you will need to /// implement every method /// </summary> public class RequestHandler : IRequsetHandler { public static readonly string VersionNumberString = String.Format("Chromium: {0}, CEF: {1}, CefSharp: {2}", Cef.ChromiumVersion, Cef.CefVersion, Cef.CefSharpVersion); private Dictionary<UInt64, MemoryStreamResponseFilter> responseDictionary = new Dictionary<UInt64, MemoryStreamResponseFilter>(); public override bool OnBeforeBrowse(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, bool userGesture, bool isRedirect) { return false; } public override bool OnOpenUrlFromTab(IWebBrowser browserControl, IBrowser browser, IFrame frame, string targetUrl, WindowOpenDisposition targetDisposition, bool userGesture) { return false; } public override bool OnCertificateError(IWebBrowser browserControl, IBrowser browser, CefErrorCode errorCode, string requestUrl, ISslInfo sslInfo, IRequestCallback callback) { //NOTE: If you do not wish to implement this method returning false is the default behaviour // We also suggest you explicitly Dispose of the callback as it wraps an unmanaged resource. //callback.Dispose(); //return false; //NOTE: When executing the callback in an async fashion need to check to see if it's disposed if (!callback.IsDisposed) { using (callback) { //To allow certificate //callback.Continue(true); //return true; } } return false; } public override void OnPluginCrashed(IWebBrowser browserControl, IBrowser browser, string pluginPath) { // TODO: Add your own code here for handling scenarios where a plugin crashed, for one reason or another. } public override CefReturnValue OnBeforeResourceLoad(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IRequestCallback callback) { Uri url; if (Uri.TryCreate(request.Url, UriKind.Absolute, out url) == false) { //If we're unable to parse the Uri then cancel the request // avoid throwing any exceptions here as we're being called by unmanaged code return CefReturnValue.Cancel; } //Example of how to set Referer // Same should work when setting any header // For this example only set Referer when using our custom scheme if (url.Scheme == CefSharpSchemeHandlerFactory.SchemeName) { //Referrer is now set using it's own method (was previously set in headers before) request.SetReferrer("http://google.com", ReferrerPolicy.Default); } //Example of setting User-Agent in every request. //var headers = request.Headers; //var userAgent = headers["User-Agent"]; //headers["User-Agent"] = userAgent + " CefSharp"; //request.Headers = headers; //NOTE: If you do not wish to implement this method returning false is the default behaviour // We also suggest you explicitly Dispose of the callback as it wraps an unmanaged resource. //callback.Dispose(); //return false; //NOTE: When executing the callback in an async fashion need to check to see if it's disposed if (!callback.IsDisposed) { using (callback) { if (request.Method == "POST") { using (var postData = request.PostData) { if(postData != null) { var elements = postData.Elements; var charSet = request.GetCharSet(); foreach (var element in elements) { if (element.Type == PostDataElementType.Bytes) { var body = element.GetBody(charSet); } } } } } //Note to Redirect simply set the request Url //if (request.Url.StartsWith("https://www.google.com", StringComparison.OrdinalIgnoreCase)) //{ // request.Url = "https://github.com/"; //} //Callback in async fashion //callback.Continue(true); //return CefReturnValue.ContinueAsync; } } return CefReturnValue.Continue; } public override bool GetAuthCredentials(IWebBrowser browserControl, IBrowser browser, IFrame frame, bool isProxy, string host, int port, string realm, string scheme, IAuthCallback callback) { //NOTE: If you do not wish to implement this method returning false is the default behaviour // We also suggest you explicitly Dispose of the callback as it wraps an unmanaged resource. callback.Dispose(); return false; } public override bool OnSelectClientCertificate(IWebBrowser browserControl, IBrowser browser, bool isProxy, string host, int port, X509Certificate2Collection certificates, ISelectClientCertificateCallback callback) { //NOTE: If you do not wish to implement this method returning false is the default behaviour // We also suggest you explicitly Dispose of the callback as it wraps an unmanaged resource. callback.Dispose(); return false; } public override void OnRenderProcessTerminated(IWebBrowser browserControl, IBrowser browser, CefTerminationStatus status) { // TODO: Add your own code here for handling scenarios where the Render Process terminated for one reason or another. browserControl.Load(CefExample.RenderProcessCrashedUrl); } public override bool OnQuotaRequest(IWebBrowser browserControl, IBrowser browser, string originUrl, long newSize, IRequestCallback callback) { //NOTE: If you do not wish to implement this method returning false is the default behaviour // We also suggest you explicitly Dispose of the callback as it wraps an unmanaged resource. //callback.Dispose(); //return false; //NOTE: When executing the callback in an async fashion need to check to see if it's disposed if (!callback.IsDisposed) { using (callback) { //Accept Request to raise Quota //callback.Continue(true); //return true; } } return false; } public override void OnResourceRedirect(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IResponse response, ref string newUrl) { //Example of how to redirect - need to check `newUrl` in the second pass //if (request.Url.StartsWith("https://www.google.com", StringComparison.OrdinalIgnoreCase) && !newUrl.Contains("github")) //{ // newUrl = "https://github.com"; //} } public override bool OnProtocolExecution(IWebBrowser browserControl, IBrowser browser, string url) { return url.StartsWith("mailto"); } public override void OnRenderViewReady(IWebBrowser browserControl, IBrowser browser) { } public override bool OnResourceResponse(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IResponse response) { //NOTE: You cannot modify the response, only the request // You can now access the headers //var headers = response.Headers; return false; } public override IResponseFilter GetResourceResponseFilter(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IResponse response) { var url = new Uri(request.Url); if (url.Scheme == CefSharpSchemeHandlerFactory.SchemeName) { if(request.Url.Equals(CefExample.ResponseFilterTestUrl, StringComparison.OrdinalIgnoreCase)) { return new FindReplaceResponseFilter("REPLACE_THIS_STRING", "This is the replaced string!"); } if (request.Url.Equals("custom://cefsharp/assets/js/jquery.js", StringComparison.OrdinalIgnoreCase)) { return new AppendResponseFilter(System.Environment.NewLine + "//CefSharp Appended this comment."); } //Only called for our customScheme var dataFilter = new MemoryStreamResponseFilter(); responseDictionary.Add(request.Identifier, dataFilter); return dataFilter; } //return new PassThruResponseFilter(); return null; } public override void OnResourceLoadComplete(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request, IResponse response, UrlRequestStatus status, long receivedContentLength) { var url = new Uri(request.Url); if (url.Scheme == CefSharpSchemeHandlerFactory.SchemeName) { MemoryStreamResponseFilter filter; if(responseDictionary.TryGetValue(request.Identifier, out filter)) { //TODO: Do something with the data here var data = filter.Data; var dataLength = filter.Data.Length; //NOTE: You may need to use a different encoding depending on the request var dataAsUtf8String = Encoding.UTF8.GetString(data); } } } } } 总结

以上为个人经验,希望能给大家一个参考,也希望大家多多支持软件开发网。



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