Unable to get PostData from IRequest

[aiqinxuancai]

Is there an existing issue for this?

• I have searched both open/closed issues, no issue already exists.

CefSharp Version

123.0.60

Operating System

Windows 10

Architecture

x64

.Net Version

.Net8.0

Implementation

WPF

Reproduction Steps

I have a program embedded with CefSharp, which I use to intercept some POST requests and process them. It has been working well for a long time, but recently it seems that the website has been updated. Without any updates or changes to my program, I am unable to retrieve the data from IRequest's PostData.
This is somewhat strange, as not all PostData cannot be retrieved, only a specific frame request on this website. In the debugging interface, I can see the FormData submitted by the request, but in the code, I cannot retrieve the PostData.

I tried testing with the simplest code possible, and the result was the same.

public class CustomRequestHandler : RequestHandler
{
    protected override IResourceRequestHandler GetResourceRequestHandler(IWebBrowser chromiumWebBrowser, IBrowser browser, IFrame frame, IRequest request, bool isNavigation, bool isDownload, string requestInitiator, ref bool disableDefaultHandling)
    {
        if (request.Method == "POST")
        {
            var postData = request.PostData;
            if (postData != null)
            {
                var elements = postData.Elements;

                foreach (var element in elements)
                {
                    if (element.Type == PostDataElementType.Bytes)
                    {
                        var body = Encoding.UTF8.GetString(element.Bytes);
                        Debug.WriteLine("PostData#2：" + body);
                    }
                }
            }
        }

        return base.GetResourceRequestHandler(chromiumWebBrowser, browser, frame, request, isNavigation, isDownload, requestInitiator, ref disableDefaultHandling);
    }
}

In Debuging.

In Code.

Expected behavior

Correctly obtaining PostData.

Actual behavior

Unable to get PostData

Regression?

Yes, I encountered this issue in version 95 of CefSharp, and I can still reproduce it after upgrading to version 123.

Known Workarounds

No

Does this problem also occur in the CEF Sample Application

Yes using WPF/OffScreen command line args

Other information

No response

[amaitland]

What is the value of https://cefsharp.github.io/api/118.6.x/html/P_CefSharp_IPostData_HasExcludedElements.htm

If the value is true then it's likely what you are seeing is expected. If it's false then you'll need to raise an issues at https://github.com/chromiumembedded/cef/issues

CefSharp is just a wrapper around the Chromium Embedded Framework.

[aiqinxuancai]

What is the value of https://cefsharp.github.io/api/118.6.x/html/P_CefSharp_IPostData_HasExcludedElements.htm

If the value is true then it's likely what you are seeing is expected. If it's false then you'll need to raise an issues at https://github.com/chromiumembedded/cef/issues

CefSharp is just a wrapper around the Chromium Embedded Framework.

I have found the reason. By setting a breakpoint in Chrome's debugging tool and looking at the parameters of window.fetch, I noticed that the data type of PostData is Blob, with an empty type, but it does have data in size. By using the code const text = await body.text(); in JavaScript, you can get the parameters.
It seems that in CEF or CefSharp, it is can't to support this type of data. Currently, I am using injected JavaScript code to get this PostData, and it works well.

[amaitland]

I suspect this is a CEF limitation, you can ask at https://www.magpcss.org/ceforum/index.php for clarification. See if the CEF maintainer thinks this is fixable.