Deploying Hazel server as sub route (for Electron auto updates) on Firebase Functions & Hosting

Readme.md

Deploy Vercel Hazel on Firebase and access it like: mySoftwareWebsite.com/get

Path "/get" can be replaced with your desired path

Related: https://github.com/vercel/hazel

fetchElectronReleases.js

const functions = require("firebase-functions");
const hazel = require("hazel-server"); // Run "npm i hazel-server" in your functions/ directory first
const express = require("express");
const cors = require("cors");

const app = express();

// Middlewares
app.use(cors());
app.use((req, res, next) => {
  // Remove trailing slash
  if (req.url.slice(-1) === "/") {
    req.url = req.url.slice(0, -1);
  }
  // Redirect "/get" to "/" since Hazel needs root url ie. "/"
  req.url = req.url.replace("/get", "/").replace("//", "/");

  // Forward request to the handler
  next("route");
});

// Internal routes are handled by Hazel
app.get("*", (req, res) => {
  hazel({
    //Git repo where releases are published
    account: YOUR_GITHUB_USERNAME,
    repository: YOUR_GITHUB_REPO_NAME,
  })(req, res);
});

module.exports.fetchElectronReleases = () => {
  return functions.https.onRequest(app);
};

firebase.json

// ++ Existing content

"hosting":[
    {
      "target": "YOUR_FIREBASE_SITE",
      "public": "YOUR_PUBLIC_DIR",
      "rewrites": [
        {
          "source": "/get/**",
          "function": "fetchElectronReleases" //This will execute given firebase function on this hosting route
        },
        {
          "source": "/get",
          "function": "fetchElectronReleases"
        },
        {
          "source": "**",
          "destination": "/index.html"
        }
      ]
    }
  ]