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CefSharp过滤图片RequestHandler问题

开发者 https://www.devze.com 2023-01-16 10:49 出处:网络 作者: MC-DEV
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
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.SetRefehttp://www.devze.comrrer("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)
                         TvGfFUBAZ       { 
                                    var elements = postData.Elements;
    
          开发者_JAVA                          var charSet = request.GetCharSet();
    
                                    foreach (var elemenpythont 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))
                        //{
                        //    rewww.devze.comquest.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 http://www.devze.comit 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我们。

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