Exception errors cause garbled text

Question

User-195907812 posted

Hi,

I have a live webforms project and I noticed a strange issue today when the database went down.

When an exception occurs, the page is returned as follows:

https://i.imgur.com/VfpzxHd.jpg

I have created a test page to manually invoke an exception, and issue is still there.

I've added the following to my webconfig, but it doesn't work:

<customErrors mode="On" redirectMode="ResponseRewrite" defaultRedirect="/uk/error_deleteme" />

Does anyone know why this is happening?

Answer 1

User753101303 posted

Hi,

The error is supposed to be shown using which language? This character is used when values are not matching a valid unicode characters but even other characters are looking weird.

If you are using a latin language I suspect it could be that you have an exception handler somewhere (when the db fails ?) that uses Response.Write to show binary data when an error happens ???

Answer 2

User-195907812 posted

Hi PatriceSc,

Any errors should be shown in English.

If I view the source it's all garbled too.

Answer 3

User753101303 posted

And in the browser or by using F12 the page encoding is ?

For now it seems really something like rendering binary data as text making mosft of them being randomly invalid ???

Answer 4

User-195907812 posted

I can't see that information anywhere using F12.

The source is as follows:


I can see an error...

It may be unrelated, but this project uses a Master Page and a nested master page though everything works fine until there is an exception.

Answer 5

User753101303 posted

Sorry, more precisely I meant F12 Network, Response headers and looking at the "Content-Type" to see if you have something such as : text/html; charset=utf-8

Edit: I confirm that random bytes are producing a similar result. For some reason it seems binary content is rendered from the server side when an exception happens ???

Answer 6

User-37275327 posted

Check this thread, But not sure your environment is same as facts on the thread.

Answer 7

User-195907812 posted

I've just tried this on a different computer (same source version), and I get the correct error:

Looking at that thread, I think it might have something to do with compression.

I added this a long time ago to Global.asax.cs:

void Application_BeginRequest(object sender, EventArgs e)
{
// Implement HTTP compression
HttpApplication app = (HttpApplication)sender;

// Retrieve accepted encodings
string encodings = app.Request.Headers.Get("Accept-Encoding");
if (encodings != null)
{
// Check the browser accepts deflate or gzip (deflate takes preference)
encodings = encodings.ToLower();
if (encodings.Contains("deflate"))
{
app.Response.Filter = new DeflateStream(app.Response.Filter, CompressionMode.Compress);
app.Response.AppendHeader("Content-Encoding", "deflate");
}
else if (encodings.Contains("gzip"))
{
app.Response.Filter = new GZipStream(app.Response.Filter, CompressionMode.Compress);
app.Response.AppendHeader("Content-Encoding", "gzip");
}
}
}

Answer 8

User-195907812 posted

Ok, so I've had a chance to re-test.

If I comment out the Application_BeginRequest method it works.

Is there another/better way of compressing my (webforms) site?

Answer 9

User-1838255255 posted

Hi RageRiot,

According to your description and error message, I found someone who meet the similar issue as you, please check the solutions: 

Page displays random symbols instead of error message on Firefox: 

https://stackoverflow.com/questions/4143536/page-displays-random-symbols-instead-of-error-message-on-firefox/27123147 

ASP.NET GZip Encoding Caveats: 

https://weblog.west-wind.com/posts/2011/May/02/ASPNET-GZip-Encoding-Caveats?Page=2 

Best Regards,
Eric Du 

Answer 10

User-195907812 posted

Perfect, thanks.

Adding...

protected void Application_Error(object sender, EventArgs e)
{
     Response.Filter = null;
}

To the Global.asax.cs worked :)