Node-RED 개념

Node-RED - 위키백과, 우리 모두의 백과사전

Node-RED Concepts : Node-RED

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Node

A Node is the basic building block of a flow.

Nodes are triggered by either receiving a message from the previous node in a flow, or by waiting for some external event, such as an incoming HTTP request, a timer or GPIO :다용도 입출력(general-purpose input/output, GPIO) hardware change. They process that message, or event, and then may send a message to the next nodes in the flow.

A node can have at most(많아 봐야[기껏해야]) one input port and as many(같은 수만큼의 (것)) output ports as it requires.

• Working with Nodes

• The Core Nodes

• Creating Nodes

Configuration(1. 배열, 배치; 배열[배치] 형태 2. 환경 설정) node

A Configuration (config) Node is a special type of node that holds reusable(재사용할 수 있는) configuration that can be shared by regular nodes in a flow.

For example, the MQTT In and Out nodes use an MQTT Broker config node to represent a shared connection to an MQTT broker.

Config nodes do not appear in the main workspace, but can be seen by opening the Configuration nodes sidebar.

• Working with Configuration nodes

• Configuration node sidebar

Flow A Flow is represented as a tab within the editor workspace and is the main way to organise [: 1. (어떤 일을) 준비[조직]하다 2. (특정한 순서·구조로) 정리하다, 체계화[구조화]하다] nodes.

The term “flow” is also used to informally describe a single set of connected nodes. So a flow (tab) can contain multiple flows (sets of connected nodes).

• Working with Flows

Context Context is a way to store information that can be shared between nodes without using the messages that pass through a flow.

There are three types of context;

• Node - only visible to the node that set the value

• Flow - visible to all nodes on the same flow (or tab in the editor)

• Global - visible to all nodes

By default, Node-RED uses an in-memory Context store so values do not get saved across restarts. It can be configured to use a file-system based store to make the values persistent. It is also possible to plug-in alternative storage plugins.

• Working with context

• Context Store API

Message Messages are what pass between the nodes in a flow. They are plain JavaScript objects that can have any set of properties. They are often referred to as msg within the editor.

By convention, they have a payload property containing the most useful information.

• Working with messages

Subflow A Subflow is a collection of nodes that are collapsed into a single node in the workspace.

They can be used to reduce some visual complexity of a flow, or to package up a group of nodes as a reusable component used in multiple places.

• Working with Subflows

Wire Wires connect the nodes and represent how messages pass through the flow.

• Working with Wires

Palette The Palette is on the left of the editor and lists of the nodes that are available to use in flows.

Extra nodes can be installed into the palette using either the command-line or the Palette Manager.

• Working with the Palette

• Adding nodes to the palette

• The Palette Manager

Workspace The Workspace is the main area where flows are developed by dragging nodes from the palette and wiring them together.

The workspace has a row of tabs along the top; one for each flow and any subflows that have been opened.

• Working with the Workspace

Sidebar The sidebar contains panels that provide a number of useful tools within the editor. These include panels to view more information and help about a node, to view debug message and to view the flow’s configuration nodes.

• Working with the Sidebar