Duplicate check

Passes a record to Output only the first time its key (the value of FilterProperty) is seen, optionally within a time window; repeats go to Already exists. Use it in front of anything that must not process the same item twice.

Pins

Pin	Kind	Types	Description
Input	input	any	Record to check.
Output	output	same as input	Record whose key was not seen (or whose earlier key expired), with the original metadata.
Already exists	continue	any	Record whose key was already seen within the window, with the original metadata.

Configuration

Field	Type	Default	Description
FilterProperty	dropdown (property of the input type)		Required. Property whose value is the duplicate key. Options appear after the input is connected.
FilterLifetimeInMsec	integer (≥ 0)	0	How long a key is remembered, in milliseconds. 0 = forever (until the flow stops).

Behaviour

• At start the component builds its own key set for FilterProperty (the input type is taken from the Input connection). Without FilterProperty the flow fails to start.
• For each record the key is added atomically: a new key, or a key whose lifetime has passed, goes to Output; a key still remembered goes to Already exists.
• Keys keep the type of the property (a number stays a number, compared by value); a record whose key is null always goes to Already exists.
• Keys are never released by later components: only the lifetime ends them.

Notes

• The key set lives in memory, belongs to this component and is empty after a flow restart. It is not shared with queues; a queue's own FilterProperty gives the same check inside the queue (and can be persisted).
• With FilterLifetimeInMsec = 0 the set grows with every distinct key for as long as the flow runs; set a lifetime for unbounded key spaces.
• Safe for parallel callers: two records with the same new key at the same time pass only once.

Example

{ "FilterProperty": "OrderId", "FilterLifetimeInMsec": 600000 }

Http listener → Duplicate check → Queue ; Already exists → Http response (409)