Error with React SPA app and POST requests in Aspnet Core 2.1 rc1 #67

New Issue

fergalmoran · 2025-08-09T17:14:53Z

fergalmoran commented

2025-08-09 17:14:53 +00:00

Originally created by @istupakov on 5/12/2018

Functional impact

Strange error when do post request to react app hosted in aspnet core 2.1 rc1

Minimal repro steps

dotnet new react
dotnet publish
run published version
Post request to localhost

Expected result

Not Found 404
No error on server

Actual result

Bad Request 400
Server Error:

fail: Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware[1]
      An unhandled exception has occurred while executing the request.
System.InvalidOperationException: The SPA default page middleware could not return the default page '/index.html' because it was not found,
and no other middleware handled the request.
Your application is running in Production mode, so make sure it has been published, or that you have built your SPA manually. Alternatively
you may wish to switch to the Development environment.

   at Microsoft.AspNetCore.SpaServices.SpaDefaultPageMiddleware.<>c__DisplayClass0_0.<Attach>b__1(HttpContext context, Func`1 next)
   at Microsoft.AspNetCore.Builder.UseExtensions.<>c__DisplayClass0_1.<Use>b__1(HttpContext context)
   at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Builder.RouterMiddleware.Invoke(HttpContext httpContext)
   at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.Invoke(HttpContext context)

Further technical details

If run in dev mode (dotnet run) - everything work as expected.

dotnet --version
2.1.300-rc1-008673

*Originally created by @istupakov on 5/12/2018* ### Functional impact Strange error when do post request to react app hosted in aspnet core 2.1 rc1 ### Minimal repro steps 1. `dotnet new react` 2. `dotnet publish` 3. run published version 4. Post request to localhost ### Expected result Not Found 404 No error on server ### Actual result Bad Request 400 Server Error: ``` fail: Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware[1] An unhandled exception has occurred while executing the request. System.InvalidOperationException: The SPA default page middleware could not return the default page '/index.html' because it was not found, and no other middleware handled the request. Your application is running in Production mode, so make sure it has been published, or that you have built your SPA manually. Alternatively you may wish to switch to the Development environment. at Microsoft.AspNetCore.SpaServices.SpaDefaultPageMiddleware.<>c__DisplayClass0_0.<Attach>b__1(HttpContext context, Func`1 next) at Microsoft.AspNetCore.Builder.UseExtensions.<>c__DisplayClass0_1.<Use>b__1(HttpContext context) at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context) at Microsoft.AspNetCore.Builder.RouterMiddleware.Invoke(HttpContext httpContext) at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context) at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context) at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.Invoke(HttpContext context) ``` ### Further technical details If run in dev mode (`dotnet run`) - everything work as expected. ``` dotnet --version 2.1.300-rc1-008673 ```

fergalmoran closed this issue

2025-08-09 17:14:53 +00:00

Sign in to join this conversation.

1 Participants

Notifications

Due Date

No due date set.

Dependencies

No dependencies set.

Reference: github/JavaScriptServices#67