MessageNode

JSONPathNode

JSONPathNode parses JSON payload of JMS messages and retrieves data from the payload according to the predifined JSONPath expressions. It then sets them into message's properties. The original JSON payload should be always stored in the message body. JSONPathNode will not modify the JSON payload. There are three outlinks, done for all parsed messages, nohit for those messages not belonging to any predefined rulesets, failure for those messages failed in the JSONPath evaluations. JSONPath is the path with dot as the delimiter, similar with those for dust.js.

JSONPathNode contains a number of predefined rulesets. These rulesets categorize messages into non-overlapping groups. Therefore, each rule defines a unique message group. The ruleset also defines the JSONPath expressions. The original JSON payload should be always stored in the message body. Due to JMS specifications, you have to clear user properties before resetting them on a readonly message. You can specify ResetOption in a ruleset so that the message header will be reset for modifications. Its value is 0 for no reset, 1 for optional reset and 2 for guaranteed reset.

JSONPathNode supports dynamic setting of jsonpath expressions. It means you can reference properties of the message in your jsonpath expressions. JSONPathNode will retrieve the data from the incoming message and compile the expressions before the evaluation.

JSONPathNode always adds an extra ruleset for the nohit messages. This nohit ruleset is always the first ruleset with the id of 0. On the node level, DisplayMask and StringProperty control the display result of outgoing messages.

You are free to choose any names for the three fixed outlinks. But JSONPathNode always assumes the first outlink for done, the second for failure and the last for nohit.

The JSONPath evaluation is executed via the pre-defined rulesets. Therefore, the configuration of the rulesets is critical to the operations of JSONPathNode. Here are complete properties of rulesets for JSONPathNode.

Property Name Data Type Requirement Description Examples

Name alphanumeric with no spaces mandatory name of the ruleset event

ResetOption integer optional option to reset properties 2 (default: 0)

JSONPath map mandatory for JSONPath only for resetting properties of messages see example

PreferredOutLink alphanumeric with no spaces mandatory for bypass only name of the preferred outlink bypass

FormatterArgument list optional list of post format operations see example

JMSPropertyGroup list optional list of pattern groups on properties to select messages see example

XJMSPropertyGroup list optional list of pattern groups on properties to exclude messages see example

PatternGroup list optional list of pattern groups on body to select messages see example

XPatternGroup list optional list of pattern groups on body to exclude messages see example

StringProperty map optional for setting the user properties on the messages see example

where JSONPath specifies the details of the JSONPath expressions. PreferredOutLink can be defined for bypass rulesets only. In this case, the messages of the group will not be parsed. Here is an example for the bypass ruleset:

Property Name	Data Type	Requirement	Description	Examples
Name	alphanumeric with no spaces	mandatory	name of the ruleset	event
ResetOption	integer	optional	option to reset properties	2 (default: 0)
JSONPath	map	mandatory for JSONPath only	for resetting properties of messages	see example
PreferredOutLink	alphanumeric with no spaces	mandatory for bypass only	name of the preferred outlink	bypass
FormatterArgument	list	optional	list of post format operations	see example
JMSPropertyGroup	list	optional	list of pattern groups on properties to select messages	see example
XJMSPropertyGroup	list	optional	list of pattern groups on properties to exclude messages	see example
PatternGroup	list	optional	list of pattern groups on body to select messages	see example
XPatternGroup	list	optional	list of pattern groups on body to exclude messages	see example
StringProperty	map	optional	for setting the user properties on the messages	see example

{
  ...
  "Ruleset": [{
    "Name": "bypass",
    "PreferredOutLink": "BYPASS",
    "JMSPropertyGroup": [{
      "JMSType": "^score$"
    }]
  }],
  ...
}

where it routes the messages to the outlink of BYPASS.

Here is an example of the JSONPath ruleset.

{
  ...
  "Ruleset": [{
    "Name": "script",
    "JMSPropertyGroup": [{
      "operation": "^start$"
    }],
    "ResetOption": "1",
    "JSONPath": {
      "ActionScript": ".Component[#{Name}=='##name##'].StartScript"
    }
  }],
  ...
}

where it extracts the content from the JSON payload and sets the value on the property of ActionScript. It expects the JSON payload contains a list of maps under the name of Component. In the expression, #{Name} is a variable referencing the value of Name in each of the maps. ##name## is the place holder referencing the value of message property of name. This expression will select one map from the list and extracts the value of StartScript from the map.

Here is an example of JSONPathNode:

{
  "Name": "node_jsonpath",
  "ClassName": "org.qbroker.node.JSONPathNode",
  "Description": "parse json messages",
  "Operation": "evaluate",
  "LinkName": "root",
  "Capacity": "6",
  "DisplayMask": "0",
  "Debug": "19",
  "Ruleset": [{
    "Name": "test",
    "ResetOption": "1",
    "JMSPropertyGroup": [{
      "JMSType": "."
    }],
    "JSONPath": {
      "FileName": ".store.book[0].path"
    }
  }],
  "OutLink": ["parsed", {
    "Name": "failure",
    "Capacity": "24",
    "Partition": "0,6"
  },{
    "Name": "nohit",
    "Capacity": "24",
    "Partition": "0,6"
  }]
}