Response compression not working

[mip1983]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I'm not sure at what point in time this has started occurring as I'm sure this has worked in the past, but I'm not longer seeing content being compressed with response compression enabled, whether that's trying to test the issue locally or when published.

In my browser tools against my published application, I'm seeing no difference between transferred over the network and resource size, with 'Content-Encoding' column being blank:

I can see in the request that it's sending the right 'Accept-Encoding' request headers:

As a test I've tried publishing my application locally on disk, and in the output I can see *.js.br and *.js.gz files that are well compressed, so it's producing the compressed output, I don't know why it's not being served up.

My Application is a Blazor Web App on .NET 9, built on .NET Aspire, published to Azure Container apps through azd.

Expected Behavior

I would expect to see a reduced size transferred over the network and 'Content-Encoding' column populated.

Steps To Reproduce

I have response compression added to my services, I've added the compression options here to see if it makes a difference but no change:

builder.Services.AddResponseCompression(static options =>
{
	options.EnableForHttps = true;
	options.Providers.Add<BrotliCompressionProvider>();
	options.Providers.Add<GzipCompressionProvider>();

	// For signalR
	options.MimeTypes = [.. ResponseCompressionDefaults.MimeTypes, "application/octet-stream"];
});

builder.Services.Configure<BrotliCompressionProviderOptions>(options => options.Level = CompressionLevel.Optimal);
builder.Services.Configure<GzipCompressionProviderOptions>(options => options.Level = CompressionLevel.Optimal);

and

app.UseResponseCompression();

Early on in my app configuration (in the case of my web app, before 'app.MapStaticAssets(), and 'MapRazorComponents' or anything else).

Exceptions (if any)

None I've seen, it just doesn't work.

.NET Version

9.0.202

Anything else?

.NET 9, Aspire 9.1, published through Azure DevOps with the latest version of azd to Azure container apps.

[javiercn]

@mip1983 thanks for contacting us.

builder.Services.AddResponseCompression(static options =>
{
	options.EnableForHttps = true;
	options.Providers.Add<BrotliCompressionProvider>();
	options.Providers.Add<GzipCompressionProvider>();

	// For signalR
	options.MimeTypes = [.. ResponseCompressionDefaults.MimeTypes, "application/octet-stream"];
});

You do not need this for static files if you are using MapStaticAssets

[mip1983]

@mip1983 thanks for contacting us.

builder.Services.AddResponseCompression(static options =>
{
	options.EnableForHttps = true;
	options.Providers.Add<BrotliCompressionProvider>();
	options.Providers.Add<GzipCompressionProvider>();

	// For signalR
	options.MimeTypes = [.. ResponseCompressionDefaults.MimeTypes, "application/octet-stream"];
});

You do not need this for static files if you are using MapStaticAssets

Hi there,

That's good to know. I've had a look at reproducing it and it does it with a vanilla project template. If I just create a new project in VS2022 Preview (Version 17.14.0 Preview 2.0), and choose the Aspire Starter Template:

That gives you a Blazor Server project, and API and an Aspire AppHost. I've changed just 'App.razor' to include a js file, nothing else, it's otherwise the vanilla template:

And that has 'app.MapStaticAssets();' in Program.cs

Then I just follow the standard instructions to publish to Azure with 'azd init' and 'azd up':

https://learn.microsoft.com/en-us/dotnet/aspire/deployment/azure/aca-deployment

This is what it's deployed:

https://webfrontend.orangemushroom-a0438756.uksouth.azurecontainerapps.io/

And if I look in Firefox developer edition for example, no real diff in transferred vs size, no content-encoding:

[mip1983]

I think I've got to the bottom of it, I believe its a fairly recent anti-virus that my org has adopted, changing the headers. I noticed this additional header:

And it looks like it's something the anti-virus does:

https://stackoverflow.com/questions/58391816/x-content-encoding-over-network-in-response-header-but-not-content-encoding