Problem
How to compress responses in ASP.NET Core.
Solution
To an empty project, configure services and middleware for compression in Startup
:
public void ConfigureServices(
IServiceCollection services)
{
services.AddResponseCompression();
services.AddMvc();
}
public void Configure(
IApplicationBuilder app,
IHostingEnvironment env)
{
app.UseResponseCompression();
app.UseMvcWithDefaultRoute();
}
Add a Home
controller with Index
action and write some data to the view:
<h2>ASP.NET Core Response Compression</h2>
@for (int i = 0; i < 10000; i++)
{
<strong>Testing Response Compression: @i</strong>
}
Notice the size and time of response, before and after compression:
Discussion
When you’re unable to use the compression features of web servers (IIS, Apache, Nginx), ASP.NET Core provides an alternate option, Response Compression middleware. It’s performance won’t match server based compression features though.
Client will send Accept-Encoding
header in its request to indicate compression capabilities. The server will response with Content-Encoding
indicating the compression used. Response Compression middleware supports gzip
compression by default.
Compression Level
The default level of compression is Fastest
, i.e., to compress as quickly as possible. You could change to Optimal
for maximum compression:
services.Configure<GzipCompressionProviderOptions>(options =>
{
options.Level = CompressionLevel.Optimal;
});
services.AddResponseCompression(options =>
{
options.Providers.Add<GzipCompressionProvider>();
});
However, notice the size and time! It took more than 1 second (compared to Fastest level) but we didn’t gain a lot in terms of size (0.4kb). You’ll need to test on actual websites to decide the appropriate level.
HTTPS Compression
Compression can be enabled for HTTPS by using EnableForHttps
however, this could lead to security issues:
services.AddResponseCompression(options =>
{
options.EnableForHttps = true;
});