Intermittent C1 WebResource.axd failure on Azure App Service

Intermittent C1 WebResource.axd failure on Azure App Service

Posted by: thanhthuyeths on 30 January 2026, 3:13 am EST

• 

  thanhthuyeths

  • Post Options:
  • Link
    Copy

  Posted 30 January 2026, 3:13 am EST - Updated 30 January 2026, 3:22 am EST

  Dear Mescius Support Team,
  
  We are currently using ComponentOne ASP.NET Core MVC with the following environment:
  
  Product: ComponentOne for ASPNET Core (MVC)
  
  Version: 6,0,20233,352
  
  Hosting: Azure App Service (Windows)
  
  Runtime: ASPNET Core (NET 9)
  
  Issue Description:
  
  We are experiencing an intermittent production issue when using C1 controls (FlexGrid, etc.) that rely on C1 WebResources (/C1Resource.axd).

  Client-side error (Chrome):
  
  Uncaught SyntaxError: Unexpected end of input
  
  Server-side log:
  
  System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values. (Parameter ‘bytes’)
  
  at System.IO.Pipelines.Pipe.Advance(Int32 bytes)
  
  at Microsoft.AspNetCore.Server.IIS.Core.OutputProducer.WriteAsync(…)
  
  at C1.Web.Mvc.WebResourceInfo.WriteContent(Stream stream)
  
  at C1.Web.Mvc.WebResourcesResult.ExecuteResult(ActionContext context)

  Observations
  
  The error seems to happen when C1Resource.axd JS/CSS is partially written to the response stream
  
  This results in truncated JavaScript, causing Unexpected end of input

  The problem:
  
  -Does not occur locally
  
  -Is not reproducible consistently
  
  -Appears to be related to streaming responses under Azure IIS / HTTP2
  
  The layout uses:

  <c1-scripts>
      <c1-basic-scripts culture="ja" />
  </c1-scripts>

  Could you please help confirm:

  1. Whether this is a known issue/limitation of C1 WebResource streaming on Azure App Service
  2. If there is an official recommendation to use static Wijmo files for cloud hosting
  3. Whether a fix or improvement is planned for WebResource handling in future versions
  4. The recommended way to obtain static Wijmo JS/CSS that matches the installed C1 version

  Thank you very much for your support.
  
  We look forward to your guidance.

  Best regards,
  
  Thuyet Phan

• 

  uttkarsh.matiyal

  

  • Post Options:
  • Link
    Copy

  Posted 2 February 2026, 2:56 am EST

  Hello Thuyet,

  We created a simple sample with FlexGrid and 'c1-basic-scripts culture=“ja” ’ but could not observe the behavior at our end while publishing the app on Azure App Service (Windows).
  
  Since, we did not find the version you mentioned “6,0,20233,352”, we used the following for testing:

  • 6,0,20233,351
  • 6,0,20233,354

  But still could not replicate the behavior.

  Sample: AspNetCore_Sample.zip

  Could you please update the sample or share a stripped-down version of your application that replicates the behavior for us to investigate further?
  
  If the information is confidential, please open a ticket on our private portal at https://developer.mescius.com/my-account/my-support for sharing the sample and further discussion.

  Also, please test the behavior with the latest version (6.0.20252.413) available and share the results with us.

  Regards,
  
  Uttkarsh.

• 

  thanhthuyeths

  • Post Options:
  • Link
    Copy

  Posted 2 February 2026, 10:15 pm EST - Updated 2 February 2026, 10:20 pm EST

  Thank you for your reply.

  Regarding this issue (Uncaught SyntaxError: Unexpected end of input), it occurs only in the Production environment, and usually only once or twice per day.
  
  We believe this may be related to the Production environment handling multiple concurrent users, while in the Test environment the issue has not been reproducible so far.

  We are currently using C1.AspNetCore.Mvc.ja version 6,0,20233,352
  
  

  

  1574×270 59.4 KB

  The layout uses the following code to load C1 scripts:

  <c1-scripts>
      <c1-basic-scripts culture="ja" />
  </c1-scripts>

  I suspect that an error occurs while loading the above code in the layout. As a result, when the page-level JavaScript tries to access C1 objects (as shown below), the error occurs because the C1 objects are not available or not fully loaded.

  Page JavaScript code:

  c1.documentReady(function () {
      var fgId = new wijmo.Control.getControl("#tbBoardLog");
      ...
  });

  In other words, if the C1 scripts fail to load correctly in the layout, the page script that depends on C1 may throw errors due to missing C1 objects.

  If you have any additional information, findings, or recommendations regarding this issue, we would appreciate it if you could share them with us.

  Thank you for your continued support.
  
  Best regards,
  
  Thuyet Phan

• 

  uttkarsh.matiyal

  

  • Post Options:
  • Link
    Copy

  Posted 3 February 2026, 7:08 am EST

  Hello Thuyet,

  We still could not reproduce the behavior. However, we have shared your concerns with the development team for further insights. [Internal Tracking ID: C1WEB-30324]
  
  We’ll update you once we have more information.

  In the meantime, we request you to test the behavior with the latest version C1.AspNetCore.Mvc.ja 6.0.20252.415 as well and share your observations with us.

  Regards,
  
  Uttkarsh.

• 

  uttkarsh.matiyal

  

  • Post Options:
  • Link
    Copy

  Posted 9 March 2026, 1:21 am EST

  Hello Thuyet,

  As per the team, the sample project shared in the query was built and tested locally with no issues observed. It was also deployed to Azure App Service (student subscription) to simulate production, and the issue could not be reproduced. The same result was observed when testing with the release JP frozen sample.
  
  If you are using a higher-tier or member subscription with a specific setup, a similar environment may be required to reliably reproduce the issue.

  We’re sorry but development team could not reproduce the behavior at their end as well. Could you please share the information on your production setup that is different from a default/standard one?

  Regards,
  
  Uttkarsh.