Return value attributes

A RESTful web service function can have return values.

The type of return values is defined by the ATTRIBUTES property. Table 1 lists the return types. Additional parameters can be specified to provide a name or description; and depending on the parameter type, other attributes might identify the parameter as optional or specify a supported data format.

A RESTful web service function must include an explicit RETURNS() clause, even if the function returns no value — use an empty RETURNS() to indicate that; otherwise, you get runtime error -9158

PUBLIC FUNCTION function-name(
    #...
    parameter-name INTEGER ATTRIBUTES(WSParam),
  
    # ...
    )
    ATTRIBUTES(
       # function attributes ...
       )
    RETURNS ( INTEGER ATTRIBUTES(WSHeader),
              STRING ATTRIBUTES (WSDescription = "Greeting")
             )
        # function code
        RETURN 3, "Hello world"
END FUNCTION
Table 1. Return values attributes
Return type Description Other attributes allowed
WSHeader The return value contains a custom header.
WSErrorHeader The return value contains a header with an HTTP error response code.
WSAttachment The return value contains a path to a file for attachment.
Response body (without WSHeader) Denotes the return value is used for transferring data in the response body. Data can be JSON, XML, text, or a file type (like an image).

Data of different MIME types can be sent in multiple parts of the same response. See Multipart requests or responses