Exceptions and HTTP
          In many situations, you may want to use common HTTP status codes to indicate
the success or failure of a user's API request. For example, if a user is
attempting to retrieve an entity which does not exist, you may want to send an
HTTP 404 status code saying No entity with the ID
          
           entity_id
          
          exists.
         
You can send such common HTTP status codes by raising an exception provided by the endpoints library as follows:
message = 'No entity with the id "%s" exists.' % entity_id
raise endpoints.NotFoundException(message)
Exceptions Provided by Endpoints
The endpoints library provides the following exceptions, corresponding to specific HTTP status codes:
| Exception | Corresponding HTTP Status Code | 
|---|---|
| 
              endpoints.BadRequestException
              | HTTP 400 | 
| 
              endpoints.UnauthorizedException
              | HTTP 401 | 
| 
              endpoints.ForbiddenException
              | HTTP 403 | 
| 
              endpoints.NotFoundException
              | HTTP 404 | 
| 
              endpoints.InternalServerErrorException
              | HTTP 500 | 
Supported HTTP Status Codes
Endpoints supports a subset of HTTP status codes in API responses. The following table describes the supported codes.
| HTTP Status Codes | Support | 
|---|---|
| HTTP 2xx | HTTP 200 is typically assumed by Endpoints if the API method returns successfully. |