如何从 XMLHttpRequest 中读取 JSON 响应内容？

Question

注意：我为此使用CefSharp 浏览器。

目标

我正在尝试从 XMLHttpRequest 读取每个 JSON 响应。

我尝试过的

public class RequestHandler : IRequestHandler
{
    public void OnResourceLoadComplete(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request,
        IResponse response, UrlRequestStatus status, long receivedContentLength)
    {
        if (request.Headers["X-Requested-With"] == "XMLHttpRequest" &&
            response.ResponseHeaders["Content-Type"] == "application/json")
        {
            var resourceHandler = new ResourceHandler();
            long responseLength;
            string redirectUrl;
            var stream = resourceHandler.GetResponse(response, out responseLength, out redirectUrl);
            using (var streamReader = new StreamReader(stream))
            {
                var responseContent = streamReader.ReadToEnd();
                Console.WriteLine(responseContent);
            }
        }
    }

    public IResponseFilter GetResourceResponseFilter(IWebBrowser browserControl, IBrowser browser, IFrame frame,
        IRequest request, IResponse response)
    {
        return null;
    }

    public bool OnBeforeBrowse(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request,
        bool isRedirect)
    {
        return false;
    }

    public bool OnOpenUrlFromTab(IWebBrowser browserControl, IBrowser browser, IFrame frame, string targetUrl,
        WindowOpenDisposition targetDisposition, bool userGesture)
    {
        return false;
    }

    public bool OnCertificateError(IWebBrowser browserControl, IBrowser browser, CefErrorCode errorCode,
        string requestUrl,
        ISslInfo sslInfo, IRequestCallback callback)
    {
        return false;
    }

    public void OnPluginCrashed(IWebBrowser browserControl, IBrowser browser, string pluginPath)
    {
    }

    public CefReturnValue OnBeforeResourceLoad(IWebBrowser browserControl, IBrowser browser, IFrame frame,
        IRequest request,
        IRequestCallback callback)
    {
        return CefReturnValue.Continue;
    }

    public bool GetAuthCredentials(IWebBrowser browserControl, IBrowser browser, IFrame frame, bool isProxy,
        string host, int port,
        string realm, string scheme, IAuthCallback callback)
    {
        return false;
    }

    public void OnRenderProcessTerminated(IWebBrowser browserControl, IBrowser browser, CefTerminationStatus status)
    {
    }

    public bool OnQuotaRequest(IWebBrowser browserControl, IBrowser browser, string originUrl, long newSize,
        IRequestCallback callback)
    {
        return false;
    }

    public void OnResourceRedirect(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request,
        ref string newUrl)
    {
    }

    public bool OnProtocolExecution(IWebBrowser browserControl, IBrowser browser, string url)
    {
        return false;
    }

    public void OnRenderViewReady(IWebBrowser browserControl, IBrowser browser)
    {
    }

    public bool OnResourceResponse(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request,
        IResponse response)
    {
        return false;
    }
}

问题

我无法读取 JSON 响应，因为 stream 为空。

问题

如何从 XMLHttpRequest 读取 JSON 响应内容？

我在这方面非常缺乏经验。所以，如果我遗漏了任何有用的信息：请告诉我，我会提供。

Answer 1

我有一个解决方案。
我正在使用 cefsharp 49。

我们在过滤器中读取它：

public class TestJsonFilter:IResponseFilter
{
    public List<byte> DataAll = new List<byte>();

    public FilterStatus Filter(System.IO.Stream dataIn, out long dataInRead, System.IO.Stream dataOut, out long dataOutWritten)
    {
        try
        {
            if (dataIn == null || dataIn.Length == 0)
            {
                dataInRead = 0;
                dataOutWritten = 0;

                return FilterStatus.Done;
            }

            dataInRead = dataIn.Length;
            dataOutWritten = Math.Min(dataInRead, dataOut.Length);

            dataIn.CopyTo(dataOut);
            dataIn.Seek(0, SeekOrigin.Begin);
            byte[] bs = new byte[dataIn.Length];
            dataIn.Read(bs, 0, bs.Length);
            DataAll.AddRange(bs);

            dataInRead = dataIn.Length;
            dataOutWritten = dataIn.Length;

            return FilterStatus.NeedMoreData;
        }
        catch (Exception ex)
        {
            dataInRead = dataIn.Length;
            dataOutWritten = dataIn.Length;

            return FilterStatus.Done;
        }
    }

    public bool InitFilter()
    {
        return true;
    }

    public void Dispose()
    {

    }
}

public class FilterManager
{
    private static Dictionary<string, IResponseFilter> dataList = new Dictionary<string, IResponseFilter>();

    public static IResponseFilter CreateFilter(string guid)
    {
        lock (dataList)
        {
            var filter = new TestJsonFilter();
            dataList.Add(guid, filter);

            return filter;
        }
    }

    public static IResponseFilter GetFileter(string guid)
    {
        lock (dataList)
        {
            return dataList[guid];
        }
    }
}

在DefaultRequestHandler : IRequestHandler 类中，我们实现了以下方法。

public IResponseFilter GetResourceResponseFilter(IWebBrowser browserControl, IBrowser browser, IFrame frame,
    IRequest request, IResponse response)
{
    /*if (request.Headers["X-Requested-With"] != "XMLHttpRequest" ||
        response.ResponseHeaders["Content-Type"].Contains("application/json")) return null;*/

    if (!response.ResponseHeaders["Content-Type"].Contains("application/json"))
    {
        return null;
    }

    var filter = FilterManager.CreateFilter(request.Identifier.ToString());

    return filter;
}

public void OnResourceLoadComplete(IWebBrowser browserControl, IBrowser browser, IFrame frame, IRequest request,
    IResponse response, UrlRequestStatus status, long receivedContentLength)
{
    if (!response.ResponseHeaders["Content-Type"].Contains("application/json"))
    {
        return;
    }

    var filter = FilterManager.GetFileter(request.Identifier.ToString()) as TestJsonFilter;

    if (filter != null)
        Console.WriteLine(filter.DataAll);
}

filter.dataAll 是我们需要的！ 我们可以使用类似的方式显示字符串：

ASCIIEncoding encoding = new ASCIIEncoding();
string data = encoding.GetString(filter.DataAll.ToArray());
Console.WriteLine(data);

最终在您的表单中使用它。

var wb = new ChromiumWebBrowser("http://www.bilibili.com/video/av8503878/")
         {
            Dock = DockStyle.Fill,
            RequestHandler = new DefaultRequestHandler()
         };