node-red-contrib-event-listener

Emit, listen for, and wait on events using nodes in Node-RED

I kept having these massive flows that would get really messy calling all over the place so the idea was to make something to help clean that up and make it much easier to understand what is happening from a glance. I tried using the built-in link nodes but the lack of labels made large flows still quite messy and hard to troubleshoot. This is meant to resolve that issue.

I spend a lot of time making these custom modules, if you use them consider donating:

Usage Example

Above is a quick flow that demonstrates one of the use cases of these nodes.

If you fire an event into the first flow the msg will be held up until you either emit the event from the second flow (and it ends up at Event debug node) or timeout happens and the original msg is sent from the second output to the Timeout debug node.

We turn the debug nodes for the second and third flow off just so we only see messages make it throug the wait for node. You can easily turn these on to verify the whole process.

Note: If you press the inject button on the first flow 4 times then press the emit event button you will get 4 msg outputs to the first node. Currently we do not support changing this but if you need this feel free to open an issue to get it added.

To use this example import the JSON for this flow found here.

Node Information

namespace node

This is the configuration node that every node uses. Events are grouped by a namespace to allow for organization and separation.

emit event node

This node will emit (send) an event. You can choose to send the full msg object as the event payload (default option) or just a specific property.

on event node

This node listens for a specified eventId and outputs all events as msg objects. If the event data is not an object it will be set to a new msg object's payload and sent.

wait for node

Configuration Timeout Handling options:

• By default, when this node receives a msg it starts listening for an event matching the configured eventId. Once that event arrives it will stop listening and output the event details to the first output. If we receive no event by timeout we instead send the original message to the second output.
• If Handling Timeout option is set to Send all events until timeout then all the received events matching the configured eventId will be sent through until the timeout is reached then a timeout msg is sent from the second output.

Configuration Event Data options:

• Set event data to msg property: When an event arrives the event data will be set to the specified msg, flow, or global scope.
• Merge events into original msg: This only works if the event payload is an object. It will be merged into the original message overriding any existing keys in msg with keys from the event data.
• Merge original msg into event: The inverse of the above option. It will be merged into the event object overriding any existing keys in the event data object with keys & values from msg.
  • If event data is not an object the original payload is sent
• Ignore event data: The original waiting msg is let free without manipulation
  • If event data is not an object the original payload is sent

The timeout can be configured statically in configuration or set to be defined from a msg, flow, or global property.

Other Packages

• node-red-contrib-matrix-chat - Matrix chat client for Node-RED
• node-red-contrib-gamedig - Query game/voice servers for information

Developers

So far me (skylord123) is the only person that has contributed towards this package. Feel free to do any pull-requests to get your name here!

License

This project is licensed under the MIT License. Check here for more information.