Example: handling expected application errors

Error handling is supported with the WSThrows and WSError attributes.

In your REST function expected errors, such as application level errors, are listed in the WSThrows attribute defined in the ATTRIBUTES clause of the function.

Example using WSError with WSThrows

In this example the HTTP status code "400" is listed in the WSThrows attribute to trap for an error when a resource is not found. The function also references the "userError" variable (@userError) defined with the WSError attribute for the description of the error at runtime.

Note: In the example, the variable userError is a record but you can define this as any suitable Genero BDL simple type.

If a customer record is not found, the WSError attributed variable is set with a specific description of the HTTP status code, and the SetRestError() method is called to return it.

IMPORT com

PUBLIC DEFINE userError RECORD ATTRIBUTE(WSError="User error")
  message STRING
END RECORD

PUBLIC FUNCTION GetCustomersNameById( id STRING ATTRIBUTE(WSQuery) )
  ATTRIBUTES(WSGet,
             WSPath="/customers",
             WSThrows="400:@userError")
  RETURNS STRING
    DEFINE s STRING
    WHENEVER ERROR CONTINUE
      SELECT lname INTO s FROM customers WHERE @id  = id
    WHENEVER ERROR STOP
    IF sqlca.sqlcode == NOTFOUND THEN
        LET userError.message = SFMT("Could not find customer id :%1",id)
        CALL com.WebServiceEngine.SetRestError(400,userError)
    END IF
    RETURN s
END FUNCTION