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Express integration

dashOtaMiddleware(options) returns a standard (req, res, next) handler. It answers the OTA routes and passes everything else on to the rest of your app.

server.mjs
import express from 'express';
import { dashOtaMiddleware, rawBodySaver } from '@dash-ota/backend';

const app = express();

// Request signatures cover the raw body. With a global JSON parser, keep the raw bytes with
// rawBodySaver, and raise the limit: release manifests can exceed express.json's 100 kB default.
app.use(express.json({ limit: '32mb', verify: rawBodySaver }));

app.use(
  dashOtaMiddleware({
    adminToken: process.env.OTA_ADMIN_TOKEN,
    storageDir: './ota-data/storage',
    dataDir: './ota-data/db',
    verifyEnrollToken: async (token) => <YOUR_SESSION_CHECK>(token),
    onConfirm: (event) => console.log('ota confirm', event.bundleId, event.status),
    logger: console,
  }),
);

app.listen(4455);

<YOUR_SESSION_CHECK> is your own function that returns true for a valid session token. The middleware applies its own size limits on top of the parser's: 64 KiB for device requests, and maxAdminBodyBytes (32 MiB by default) for authenticated admin requests.

Mount it at the root​

The routes are absolute (/ota/v2/*, /admin/*, /health, /ready). The device signs the request path it sends, so the path the server sees has to be the same.

app.use(dashOtaMiddleware(options));        // correct
app.use('/ota', dashOtaMiddleware(options)); // breaks signature verification

The raw body​

The device signs the method, path, install id, nonce, timestamp and the SHA-256 of the body, so the server has to check the exact bytes it received. Either:

  1. mount dashOtaMiddleware before any body parser (it reads the stream itself), or
  2. keep your global express.json() and add verify: rawBodySaver, which keeps the raw bytes on req.rawBody.

A request with an empty or malformed JSON body gets 400 bad_request either way.

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