node-red-flow-notes

Objectives

• To create a server based web application, to quickly scribble or store notes from any device in the local network.
• The application should be simple with few input fields and buttons to add, update, delete, copy, clear and export notes.
• The notes to be stored in a text file in JSON format.
• The application to run on a Raspberry Pi.
• The application is for Private Use only.

Solution

Node-RED selected as the development tool running on a Raspberry Pi. Two flows are defined, one for mobile use (smartphone) and the other for larger screen, i.e. desktop or tablet. The desktop has some more functions. Functionality

• Form with fields Subject (input), Content (textarea), ID (input readonly, created automatically)
• Note selection list - mobile: dropdown (ui_dropdown), desktop: list (ui_template)
• Buttons to
  • Add the newly created note
  • Update the selected note
  • Delete the selected note
  • Copy the selected note to the clipboard
  • Export all notes to a text file (with extention .exp) located in the notes folder
  • Clear all notes (Desktop only)

The notes are stored in a single text file in JSON format, located by default in the folder: /home/pi/notes.json

Note: pi is the username used.

The JSON format, is an array with note objects:

[{note 1},{note N}].

Each note has three properties:

{"id":NN,"subject":"SUBJECT","content":"CONTENT"}

Hardware

• Raspberry Pi 3B+

Software

• Raspian OS - Raspbian GNU/Linux 10 (buster)
• Node-RED v1.0.6, node-red-dashboard v2.22.1 Note: The software versions are subject to change.

Flows

The flow are stored in the files:

• node-red-flow-notes-mobile.flow
• node-red-flow-notes-desktop.flow

Installation

• Import the flows into Node-RED, either both or mobile / desktop only.
• The Node-RED tabs created are Notes Mobile and/or Notes Desktop.
• Copy the file notes.json to the folder /home/pi
• Depending username used, the path to the notes file has to be adjusted (Function node "Set Flow Context, Set flow.filename). Default is user "pi" with filename /home/pi/notes.json.

Notes

• Instead installing on a Raspberry Pi any other hardware can be used.
• Application error handling is not fully covered.
• If the list is cleared, recommend to clear the browser cache.