How To Fix /IWFND/CM_MGW091 - eTag handling not supported for this function import

SAP Error Message - Details

• Message type: E = Error

• Message class: /IWFND/CM_MGW -

• Message number: 091

• Message text: eTag handling not supported for this function import

Self-Explanatory Message

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Smart SAP Assistant

• What is the cause and solution for SAP error message /IWFND/CM_MGW091 - eTag handling not supported for this function import ?

  The SAP error message /IWFND/CM_MGW091 eTag handling not supported for this function import typically occurs in the context of SAP Gateway services when you are trying to use eTag handling with a function import that does not support it. Here’s a breakdown of the cause, potential solutions, and related information:
  Cause
  
  Function Import Limitation: The function import you are trying to call does not support eTag handling. eTags are used for concurrency control and caching, and not all function imports are designed to handle them.
  Service Configuration: The OData service may not be configured to handle eTags for the specific function import.
  Request Type: The request type (GET, POST, etc.) may not be appropriate for the function import you are trying to execute.
  
  Solution
  
  
  Check Function Import Definition: Review the definition of the function import in the OData service. Ensure that it is designed to support eTag handling. If it is not, you may need to modify the service or use a different approach.
  
  
  Modify Service Implementation: If you have control over the service implementation, consider adding eTag support to the function import if it makes sense for your use case.
  
  
  Use Appropriate Request Type: Ensure that you are using the correct HTTP method for the function import. For example, if the function import is designed to be called with a POST request, ensure that you are not trying to call it with a GET request.
  
  
  Disable eTag Handling: If eTag handling is not necessary for your use case, you can modify the client-side code to avoid sending eTag headers when calling the function import.
  
  
  Check Service Metadata: Use the service metadata (usually accessible via the $metadata endpoint) to verify the capabilities of the function import and see if eTag handling is mentioned.
  
  
  Related Information
  
  SAP Gateway Documentation: Refer to the official SAP Gateway documentation for more details on function imports and eTag handling.
  OData Protocol: Understanding the OData protocol and how it handles concurrency and caching can provide insights into why certain features are supported or not.
  SAP Community: Check the SAP Community forums for similar issues and solutions shared by other users.
  
  Conclusion
  The error /IWFND/CM_MGW091 eTag handling not supported for this function import indicates a limitation in the function import's ability to handle eTags. By reviewing the function import's definition, ensuring the correct request type, and possibly modifying the service implementation, you can resolve this issue.