node-red-contrib-infocache
** SUPERSEDED: It is likely that this module will not get developed. I'm adding a new node to the uibuilder module instead. That has been added to the uibuilder vNext branch already and will be published with uibuilder v5.**
Cache & replay messages. Optionally by topic and client or user id. Replay the cache or a part of it on request.
Introduction
This is a node for Node-RED. It is designed to provide a temporary cache of input messages so that they can be replayed on request.
It can be used in any flow but it is also designed as a companion to node-red-contrib-uibuilder which provides an easy web app builder for Node-RED. While uibuilder provides a dynamic communications channel between the Node-RED server and each connected client browser, when a client connects (or the user reloads the page), any dynamic data is lost and the client has to wait for future messages to arrive. This node allows that issue to be resolved. uibuilder sends control messages when clients connect, disconnect and when they are ready to receive data. These messages come from port 2 on the uibuilder node and you can feed that port directly into an InfoCache node. By default, the "ready for content" uibuilder control message will trigger the InfoCache node to send the contents of the cache for that client only.
There are a number of settings that you can apply that will control how much data is cached and how/when it is cleared. You may need to use some or all of these if you are passing a large number of messages/topics through the cache. No hard limits are applied other than those settings and it is perfectly possible to crash Node-RED by filling up the memory if you overdo the cache.
Contents
Features
Urm, not a lot so far!
Documentation
The documentation can be found in the docs folder. This is also published to https://totallyinformation.github.io/node-red-contrib-infocache.
Future Features
Please see the design document.
Known Issues
None at this time
To Do
The backlog of ideas and enhancements is in the To Do file
Changes
See the Change Log for details of changes made.
Dependencies
See the package.json file.
Install
Install via the palette manage in the Node-RED admin ui (no restart needed).
Alternatively run the following command in your Node-RED user directory (typically ~/.node-red):
npm install node-red-contrib-infocache
then restart Node-RED and add an instance of the InfoCache node.
You can install a specific published version with (change latest to desired version):
npm install node-red-contrib-infocache@latest
You can also install a specific unpublished branch from GitHub with (change security to desired branch):
npm install node-red-contrib-infocache@security
You can also install a specific unpublished tag (version) from GitHub with (change v0.0.1 to desired release tag):
npm install [email protected]
Node Configuration
See the node configuration document.
Recognised Input Message Structures
See the input messages document.
Examples
See the library examples for examples of use, these are flows that can be imported in Node-RED.
Some additional examples may also appear in the WIKI or the uibuilder WIKI.
Discussions and suggestions
Please use the Node-RED Discourse Forum for general discussion about this node.
Alternatively use the GitHub issues log for raising issues or contributing suggestions and enhancements.
Contributing
If you would like to contribute to this node, you can contact Totally Information via GitHub or raise a request in the GitHub issues log.
If submitting code (preferably via a pull request), please use eslint to adhere to the same standards.
When contributing code, please use the following coding standards:
- Use ESLint:Standard settings plus the following
- Indents must be 4 spaces
- Strings must be single quoted not double
- Semi-colons should not be used unless absolutely necessary (see here for guide)
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