How to keep json config file for custom node and access in HTML

General
1

Hello All,

I want to have one config file json with key:value pairs for my custom nodes. I want to access config values in my multiple custom node. so want to keep it in one file.
node_config.json:

{
   key1: value1, 
   key2: value2
}

I want to access this content in my HTML file during oneditprepare of my custom node.

Is there any way or can I put my json content in node settings.js and access it in my custom node onediprepare() funtion.

2

Trying to understand your demands, this sounds like a typical use case for Configuration nodes.

In short, this is a special type of node used to store (config) data that is shared between a number of nodes. Thus it eliminates the need to access settings.js or store data (manually) in the file system.

3

@ralphwetzel
I checked configuration node.
It seems to be too explicit. where I have to create special node for config.
I have query:

  • Will it be able to access those configs in HTML file if i go with this approach ?
  • Will it be a new node created on palatte under category config ?
4

Depends on your definition of "access". Check the chapter "Using a config node" in the linked documentation for how this looks like in the editor.

No. Config nodes don't appear in the palette. They are created on demand via the property editor of a node that uses this config data. Again: Check the linked documentation for how this looks like; picture borrowed from there:

image

Config nodes that carry data (e.g. have been created) show up at the right hand panel labeled "Configuration nodes".

5

Are you wanting to persist the file so the data survives between restarts of Node-RED or the server?

If not, all you need is a shared module accessible to all instances of your nodes.

To persist the data, you could use node-red's context store but that requires users of your node to set up a retained context store in settings.js. Or you could simply write to the filing system of the node-red server, though that will limit your node to only be used on servers with filing systems (FlowForge does not have one).

Otherwise, a config node will work. If you only ever want a single config node, you could automatically create it in code and wouldn't need to show it to users.

6

Hi @TotallyInformation,
Yes I want to have that file persistent even on multiple restarts.

I thought to read content of config.json file in custom node's js file and store it in flow context.

But, Can we access that flow context store in oneditprepare() of my custom node's HTML file?

7

You would probably want the node context store. However, content stores are not persisted by default. You have to configure Node-RED with a persistent store, for example the file store or redis store. That is done in each Node-RED instance in settings.js. So it really depends on you having some control over that - which may be fine for you but if you are providing for multiple customers, it might be tricky.

No, you cannot do that directly. The standard method is for your custom node to provide an admin API to get access.

Again though, unless you want other nodes to have access to the data - which obviously can be dangerous - use the node context (confusingly just called "context") if you can because only instances of your custom node will have access and each node instance will have its own copy of the data.

8

Hello @TotallyInformation
As you suggested, I have tried mix of context store (in js file) and in for HTML used RED admin endpoint
It solved the issue..
Thank you for your help.

1 Like
9

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