Node-RED nodes

Overview of standard nodes that are used in standard flows and to create custom flows.

Prerequisites

You need a working cenTaur cluster with the Node-RED manager to access the Node-RED admin console.

Introduction

Node-RED business flows are built from nodes. Nodes can be wired one to another via their input and output ports. Some nodes have two or more output ports.

If two nodes are wired, the first node hands over a message (msg) to the second node. The msg context is also called local context. Messages consist of JavaScript objects that can have a set of properties. The default property is the msg.payload. Other properties can be passed from one node to another.

Payload

In cenTaur, the msg.payload is used to pass data and process it in a flow. The payload can be an object, a string, or an array. So-called parser nodes convert the payload from strings to objects and vice versa, without changing the actual payload. If the output payload of a node is an array, each element of the array is represented as an output port of this node.

JSON schema

Nodes are stored as JSON objects. You can import and export nodes of a flow or all flows in a flows.json file. The file contains the node configurations and the flow configurations.

The generic JSON node schema is as follows:

{
   "id": "NODE_ID",
   "type": "NODE_TYPE",
   "name": "NODE_NAME",
   "x": HORIZINTAL_POSITION,
   "y": VERTICAL_POSITION,
   "z": "TAB_REFERENCE",
   "wires": []
 }

Depending on the node type, other attributes are required in the configuration. For more information, see the documentation of each node type.