JSONP support in the JSON domain

JSONP (JavaScript Object Notation with Padding) is an extension of the JavaScript Object Notation (JSON) format.

IBM® App Connect Enterprise provides support for JSONP services. A JSONP service, or Remote JSON Service, is a web service that returns JSON data padded with a user-defined JavaScript function call. The JSONP response message can be interpreted as an executable script, so this functionality can be used to create cross-domain function calls.

For example:

http://brokerhost:7080/flowUrlPathSuffix?jsonp=scriptFn

This URL includes a query string, where:

jsonp tells the JSONP service that any response from the URL must be returned as a JSONP message
scriptFn is the name of a client-side executable function

Responses to the URL would therefore be in the JSONP format:

scriptFn(response)

The JSON message tree provides a top level Padding element, into which the JSON parser places the name of the client-side JSONP function. Similarly, the JSON serializer pads a JSON message if the top-level element Padding is present in the tree.

For more information about JSON, see JSON parser and domain.

For information about how to use IBM App Connect Enterprise to provide a JSONP service, see Providing a JSONP service.

For information about how to use IBM App Connect Enterprise to consume a JSONP service response, see Consuming a JSONP service response.

Example JSONP message

The following example shows a simple JSONP message:

scriptFn (
    {
        "name" : "John Doe",
        "age" : -1.0,
        "known" : false,
        "address" : { "street" : null,
                      "city" : "unknown" },
        "belongings" : ["item1", "item2", "item3"]
    }
)

This JSONP input produces the following integration node logical message tree:

  (0x01000000:Object):JSON            = ( ['json' : 0xd55fc8]
    (0x03000000:NameValue):Padding = 'scriptFn' (CHARACTER)
    (0x01000000:Object   ):Data    = (
      (0x03000000:NameValue):name       = 'John Doe' (CHARACTER)
      (0x03000000:NameValue):age        = -1E+0 (FLOAT)
      (0x03000000:NameValue):known      = FALSE (BOOLEAN)
      (0x01000000:Object   ):address    = (
        (0x03000000:NameValue):street = NULL
        (0x03000000:NameValue):city   = 'unknown' (CHARACTER)
      )
      (0x01001000:Array    ):belongings = (
        (0x03000000:NameValue):Item = 'item1' (CHARACTER)
        (0x03000000:NameValue):Item = 'item2' (CHARACTER)
        (0x03000000:NameValue):Item = 'item3' (CHARACTER)
      )
    )
  )