What is ETag in SAP BC-ESI-RAP - RESTful ABAP Programming Model?

SAP Term: ETag

• Component: BC-ESI-RAP

• Component Name: RESTful ABAP Programming Model

• Description: A field that is used to determine changes to the requested resource Usually, fields like last changed timestamp, hash values, or version counters are used as ETags. An ETag can be used for optimistic locks in the OData protocol to help prevent simultaneous updates of a resource from overwriting each other. In a draft scenario, the ETag check is used to determine whether two representations of a business entity, such as an active instance and the corresponding draft BO instance, are the same. Whenever the representation of the entity changes, a new and different ETag value is assigned.

Smart SAP Assistant

• Key Concepts: 
  ETag (Entity Tag) is an HTTP response header used in the BC-ESI-RAP RESTful ABAP Programming Model. It is a unique identifier for a specific version of a resource, which is used to determine whether the resource has changed since the last request. The ETag is generated by the server and sent to the client in the response header. 
  
  How to use it: 
  The ETag can be used to determine if a resource has changed since the last request. When making a request, the client can include an If-None-Match header with the ETag value from the previous response. If the resource has not changed, then the server will respond with a 304 Not Modified status code. If the resource has changed, then the server will respond with a 200 OK status code and include an updated ETag in the response header. 
  
  Tips & Tricks: 
  When using ETags, it is important to remember that they are only valid for a single version of a resource. If the resource is modified, then a new ETag will be generated and sent in the response header. 
  
  Related Information: 
  For more information about ETags and how they are used in the BC-ESI-RAP RESTful ABAP Programming Model, please refer to SAP Help Portal documentation.