node-red-contrib-map 1.0.4

Map property values based on configurable mapping

npm install node-red-contrib-map

This is a Node-RED plugin that provides a new mappings category with the following nodes:

• map: Allows for mapping a configurable property from an input message to a configurable property on the output message, based on the configured mappings. For example, given an input message containing topic:deviceId, this node can add add a message property topicName:deviceName.
• set: Allows for adding a configurable property based on a specific mapping in the configured mappings. For example, this allows for adding a property topic:deviceId for a given device to any input message.
• switch: Allows for switching between one or more outputs based on configured mappings. For example, given an input message containing topic:deviceId, you can define separate outputs for device id deviceId1 and deviceId2.

All mappings are configured through a configuration node, meaning that each of the nodes listed above can re-use a pre-configured mapping. For example, you can have one configuration that maps input device id's to device names, and another configuration that maps device names to output device id's.

Configuration node

The following screenshots show example settings for the configuration node:

The configuration on the left shows input device mappings, which can be used to map incoming device id's to corresponding device names. Likewise, the configuration on the right shows output device mappings, which can be used to map device names to corresponding device id's.

Note that all nodes allow for selecting whether to use the left or right column from the mappings. As such, even though the primary purpose of the input device mappings configuration is to map input device id's to names, you can also map input device names to id's.

Map node

The following screenshot shows an example configuration for the map node:

In this example:

• We use the mappings provided by the ExampleInputDevices configuration
• We look up the device id, contained in the msg.topic property of the incoming message, in the list of mappings provided by ExampleInputDevices
• If a matching mapping is found, we set the msg.inputDeviceName property on the outgoing message to the corresponding device name
• We will do a case-insensitive look-up; for example myDeviceId will match MYDEVICEID
• If no mapping is found, we will still forward the message and set msg.inputDeviceName to Unknown: [topic from incoming message]

Set node

The following screenshot shows an example configuration for the set node:

In this example:

• We use the mappings provided by the ExampleOutputDevices configuration
• We set the msg.topic property on the outgoing message to the device id for Output device 3

Switch node

The following screenshot shows an example configuration for the switch node:

In this example:

• We use the mappings provided by the ExampleInputDevices configuration
• If the msg.topic property from the incoming message matches the device id for Input device 1, the message will be routed to output 1
• Likewise, if the msg.topic property from the incoming message matches the device id for Input device 2, the message will be routed to output 2
• In the flow editor, the outputs will be labeled with the device name, i.e. Input Device 1 and Input Device 2 in this example

Simple flow examples

The following sections show some example flows with the various nodes provided by this plugin.

Add Device Names

This flow demonstrates the map node.

If a mapping exists for the input device id, this flow adds the input device name to the message if a mapping exists. If no mapping exists, this flow will add Unknown: [device id] as the input device name.

If the given input device is mapped to a corresponding output device (i.e. if a motion sensor directly controls some output device), this flow will also add the output device name to the message. If no output device is known for the given input device, this flow will add None as the output device name.

The JSON configuration for this flow can be found here: addDeviceNames-flow.json.

Select Output Device

This flow demonstrates the set node.

Given some input trigger, this flow will send a message to an output device configured through the output device mapping configuration.

The JSON configuration for this flow can be found here: selectOutputDevice-flow.json.

Switch on Input Device

This flow demonstrates the switch node.

Given some input message, this flow will select between switch outputs based on the configured device mapping configuration.

The JSON configuration for this flow can be found here: switchOnInputDevice-flow.json.

Screenshots of more elaborate examples

The following screenshots show more eleborate examples on how to use the nodes provided by this plugin. These screenshots are taken from my own Node-RED configuration. To avoid potentially leaking sensitive information, only screenshots and generic descriptions are provided; no JSON flows are available.

RFXCom In

For every input provided by node-red-contrib-rfxcom, this flow does the following:

• Add a msg.deviceType property using the standard Node-RED change node. For example, msg.deviceType can be set to lights or blinds.
• Add a msg.inputDeviceName property using the map node provided by this plugin, configured with mappings between input device id's and input device names.
• Add a msg.outputDeviceName property using the map node provided by this plugin, configured with mappings between output device names and output device id's.
• The resulting message is sent to the debug output, a Telegram message, and to a link out node to which other flows can connect.

RFXCom Out

This flow provides the two link in nodes named OUT_RFX and OUT_RFX_DEVICE_NAME.

OUT_RFX:

• Expects msg.topic to contain the output device id, and msg.payload to contain the output device action.
• Sends the message as-is to the rfx-lights node.
• Retrieves the device name for the device id given in msg.topic, using the map node provided by this plugin configured with mappings between output device names and device id's, and then logs the message and sends a Telegram message containing the output device name and action.

OUT_RFX_DEVICE_NAME:

• Expects msg.outputDeviceName to contain the output device name, and msg.payload to contain the output device action.
• Add the msg.topic property containing the device id corresponding to the given output device name, using the map node provided by this plugin, configured with mappings between output device names and output device id's.
• Invokes the OUT_RFX link with the updated message.

HTTP Control

This flow takes incoming HTTP GET requests to /device, extracts the device name and action from the request parameters, and then invokes OUT_RFX_DEVICE_NAME (see above). Note that this flow doesn't use any of the nodes provided by this plugin, but it utilizes the device name to device id mapping provided by the OUT_RFX_DEVICE_NAME link.

Night Light

This flow is triggered around sunset to turn on a night light, and triggered at a specific time to turn the night light off again. It utilizes the set node provided by this plugin to set msg.topic to the output device id to be controlled.

Version history

• 1.0.4: Fixed missing configuration elements in recent Node-RED versions
• 1.0.3: Fixed handling of empty output values
• 1.0.2: Fixed handling of input values that are null or not a string
• 1.0.1: Some documentation updates & fixes
• 1.0.0: Initial version