Description
Describe the bug
I have a ASP.NET middleware which temporarily replaces the HTTP response body stream with a memory stream so that it can perform work involving seek operations on the response stream before the response is sent to the client. The code works properly when running locally using Kestrel or the integration tests server, but when running on AWS, all response bodies are duplicated (i.e. {"foo":"bar"} becomes {"foo":"bar"}{"foo":"bar"}).
Expected Behavior
The response should be a valid JSON result on all hosting environments (e.g. {"foo":"bar"}).
Current Behavior
The response is invalid when running on AWS Lambda only (duplicated JSON, e.g. {"foo":"bar"}{"foo":"bar"}).
Reproduction Steps
Simplified middleware code looks like this:
public async Task InvokeAsync(HttpContext context)
{
Stream originalResponseBodyStream = context.Response.Body;
using var buffer = new MemoryStream();
context.Response.Body = buffer;
try
{
await this._next(context);
// Do work involving seek on body stream
}
finally
{
context.Response.Body.Seek(0, SeekOrigin.Begin);
await context.Response.Body.CopyToAsync(originalResponseBodyStream);
context.Response.Body = originalResponseBodyStream;
}
}Possible Solution
No response
Additional Information/Context
My ASP.NET application is using the Minimal API hosting pattern. The AWS Lambda hosting mode is set to LambdaEventSource.RestApi.
AWS .NET SDK and/or Package version used
- Amazon.Lambda.AspNetCoreServer 7.1.0
- Amazon.Lambda.AspNetCoreServer.Hosting 1.1.0
Targeted .NET Platform
.NET 6
Operating System and version
AmazonLinux