node-red-contrib-datamatrix-restore

Node-RED node Code restore. It crops a noisy QR or Data Matrix photo (including industrial DPM), reads the code, and returns the scanned text.

The same node runs on Windows, Linux, and ARM. Install dependencies on the machine that runs Node-RED. Do not copy node_modules between operating systems.

Requirements

• Node.js 18 or later
• Node-RED 3.0 or later
• Internet only during npm install (so sharp can download the native binary for that OS/CPU)

Install

Palette Manager (after the node is in the Node-RED library)

1. Menu → Manage palette → Install
2. Search for datamatrix-restore or Code restore
3. Install node-red-contrib-datamatrix-restore
4. Restart Node-RED if the editor asks you to

npm (recommended)

In your Node-RED user directory:

cd ~/.node-red
npm install node-red-contrib-datamatrix-restore

Windows:

cd %USERPROFILE%\.node-red
npm install node-red-contrib-datamatrix-restore

Restart Node-RED. The node appears in the palette as Code restore.

From GitHub

cd ~/.node-red
npm install rivasrayos/node-red-contrib-datamatrix-restore

From a local clone

git clone https://github.com/rivasrayos/node-red-contrib-datamatrix-restore.git
cd ~/.node-red
npm install /path/to/node-red-contrib-datamatrix-restore

Docker / offline devices

If the Node-RED host has no outbound internet, npm install on that device will fail.

On a PC with internet, install native modules for the target OS, then copy the package (including node_modules) into the Node-RED user directory.

Example for Alpine Linux ARM64:

npm install --omit=dev --cpu=arm64 --os=linux --libc=musl

Copy the folder into node_modules/node-red-contrib-datamatrix-restore inside the Node-RED user directory and restart Node-RED.

zxing-wasm is loaded from the local .wasm file. The node does not download WASM at runtime.

Flow

image URL or Buffer → Code restore → debug

A separate crop node is not required. Send the image in msg.payload and { x, y, width, height } in msg.crop.

Input

| Property | Type | Description | | --- | --- | --- | | msg.payload | string or Buffer | Image URL or image Buffer (configurable) | | msg.crop.x | number | Crop left | | msg.crop.y | number | Crop top | | msg.crop.width | number | Crop width | | msg.crop.height | number | Crop height |

Output

| Property | Type | Description | | --- | --- | --- | | msg.payload | string | Scanned text | | msg.format | string | QR or DataMatrix | | msg.image | Buffer | Clean 200×200 PNG | | msg.original | Buffer | Cropped photo |

If the code cannot be read, the node reports an error and does not send a message.

License

MIT