mqtt-file-transfer

A simple Node.js module for transferring files over MQTT using streams.
Supports multiple concurrent transfers and verifies file integrity with SHA-256 checksums.

Features

• Stream files via MQTT in chunks
• Emit progress events
• Verify checksum and file size
• Support multiple concurrent transfers

Installation

npm install mqtt-file-transfer

Usage

Transmitter

import { createReadStream } from "fs";
import mqtt from "mqtt";
import { MqttTransmitter } from "mqtt-file-transfer";

const client = mqtt.connect("mqtt://localhost:1883");
const stream = createReadStream("path/to/file.txt");

const transmitter = new MqttTransmitter({
  client,
  topic: "file-transfer",
  stream,
  props: {
    pendingAckTimeout: 5000, // ms to wait for a chunk ACK before retrying/failing
    throttling: 50, // ms delay between chunks
    retry: 3, // number of retries per chunk on ACK timeout
  },
});

transmitter.on("progress", (percent) => console.log("progress", percent));
transmitter.on("error", (err) => {
  console.error("error", err);
  transmitter.stop();
});

transmitter.on("done", ({ fileName, checksum }) => {
  console.log("done", fileName, checksum);
  transmitter.stop();
});

transmitter.start();

Transmitter props (optional)

| Option | Default | Description | | ------------------- | ------- | --------------------------------------------------------- | | pendingAckTimeout | 5000 | Milliseconds to wait for a chunk ACK before retry/failure | | throttling | 50 | Milliseconds delay between sending each chunk | | retry | 3 | Number of retry attempts per chunk before giving up |

Receiver

import mqtt from "mqtt";
import { MqttReceiver } from "mqtt-file-transfer";

const client = mqtt.connect("mqtt://localhost:1883");

const receiver = new MqttReceiver({
  client,
  topic: "file-transfer",
  outputDir: "./downloads",
  props: {
    pendingChunkTimeout: 20000, // ms to wait for the next chunk before failing
  },
});

receiver.on("start", (fileName) => console.log("started", fileName));
receiver.on("progress", (percent) => console.log("progress", percent));
receiver.on("done", ({ fileName, checksum }) => {
  console.log("done", fileName, checksum);
  receiver.stop();
});
receiver.on("error", (err) => {
  console.error("error", err);
  receiver.stop();
});

receiver.start();

Receiver props (optional)

| Option | Default | Description | | --------------------- | ------- | ----------------------------------------------------------------------- | | pendingChunkTimeout | 20000 | Milliseconds to wait for the next chunk before emitting a timeout error |

License

MIT