CoreWebView2_WebResourceRequested not providing binary multi-part POST Data in Request.Content

[RickStrahl]

I have an application that captures Web Request data for later playback (WebSurge). This works great for standard text based content be it API requests or captured form data - the data gets captured into the Request stream and I can grab it out of there. Works great.

However, if the data is multi-part form data with binary data, the Request.Content is always null:

In contrast, here is a POST request with standard form data which does work and returns a Request.Content stream:

So for some reason it looks if the data is multi-part or contains binary data the request content is not provided.

AB#38186390

[champnic]

Thanks for the bug report @RickStrahl! I've added this to our backlog.

[RickStrahl]

Is there any word on whether this will be addressed?

Tested today with latest version and found this still doesn't work. Confirmed that:

• as soon as binary content is included in form data, the .Content property is null.
• multi-part forms with text only fields work fine

[RickStrahl]

@champnic Ping! Any progress or at least confirmation that this is a bug and will get addressed in the future? Or a workaround?

[champnic]

Thanks for the ping Rick. @yildirimcagri do you have any info on this issue?

[SharpEnvelope]

I also ran into exactly this issue. Ran into it when using WebView2 from C++ but also reproduced it in C# WinForms.

This can be reproduced with the following JavaScript code:

const obj = { hello: "world" };
const blob = new Blob([JSON.stringify(obj, null, 2)], {
    type: "application/json",
});

const data = new FormData();
data.append("val1", "val1");
data.append("blob", blob);

const req = new XMLHttpRequest();
req.addEventListener("load", () => {
    alert("Received: " + req.responseText);
});
req.open("POST", "https://post.asset/");
req.send(data);

And the following C# code:

this.webView2Control.CoreWebView2.WebResourceRequested += CoreWebView2_WebResourceRequested;
this.webView2Control.CoreWebView2.AddWebResourceRequestedFilter("https://post.asset/", CoreWebView2WebResourceContext.All);

private void CoreWebView2_WebResourceRequested(object sender, CoreWebView2WebResourceRequestedEventArgs eventArgs)
{
    System.IO.Stream content = eventArgs.Request.Content;

    if(content != null)
    {
        byte[] bytes = new byte[content.Length + 10];
        content.Read(bytes, 0, (int)content.Length);

        var stringData = System.Text.Encoding.Default.GetString(bytes);
        MessageBox.Show("Received: " + stringData);
    }
    else
    {
        MessageBox.Show("No content stream :(");
    }

    eventArgs.Response = this.webView2Control.CoreWebView2.Environment.CreateWebResourceResponse(null, 200, "OK", "");
}

The attached solution contains a running sample:
WebView2BinaryResourceIssue.zip

[yildirimcagri-msft]

Thanks for the sample code for this. I missed the earlier ping about this, but I will prioritize this issue now.

[stffabi]

Seeing the same behaviour in a Wails application.

[RickStrahl]

Any update on this @yildirimcagri? @champnic?

[SharpEnvelope]

Are there any plans to address this issue @yildirimcagri-msft?

[visuall]

Same for me. The WebResourceRequested handler is the only way to intercept/filter requests and this bug makes this impossible. @yildirimcagri-msft , you say you will prioritize this issue for the last year or so and still nothing. Will it be possible finally this issue to be solved ?