index.js

#!/usr/bin/env node

const express = require("express");
const { loadConfig } = require("./lib/config");
const { createCorsMiddleware, errorHandler } = require("./lib/middleware");
const { healthCheck } = require("./lib/routes");
const {
  handleDocumentUpload,
  handleDocumentStatus,
  handleDocumentDownload,
  createDeeplProxy,
  upload,
} = require("./lib/proxy");

const config = loadConfig();
const baseUrl = config.deepl.base_url;
const app = express();

app.use(createCorsMiddleware());
app.use(express.urlencoded({ extended: true }));

app.get("/health", (req, res) =>
  healthCheck(req, res, config.deepl.api_key, baseUrl)
);

app.post(
  "/v2/document",
  upload.single("file"),
  (req, res, next) =>
    handleDocumentUpload(req, res, config.deepl.api_key, baseUrl, next),
);

app.post("/v2/document/:documentId", (req, res, next) =>
  handleDocumentStatus(req, res, config.deepl.api_key, baseUrl, next),
);

app.post("/v2/document/:documentId/result", (req, res, next) =>
  handleDocumentDownload(req, res, config.deepl.api_key, baseUrl, next),
);

// Proxy all other DeepL API requests
const deeplProxy = createDeeplProxy(config.deepl.api_key, baseUrl);
app.use(deeplProxy);

// Error handling middleware (must be last)
app.use(errorHandler);

// Use 0.0.0.0 in Docker, 127.0.0.1 locally for security
const host = process.env.HOST || "127.0.0.1";
const port = config.server.port;

const server = app.listen(port, host, () => {
  console.log("===================================");
  console.log("DeepL API Proxy");
  console.log("===================================\n");
  console.log(`Proxy: http://${host}:${port}`);
  console.log("\nPress Ctrl+C to stop\n");
});

server.on("error", (err) => {
  if (err.code === "EADDRINUSE") {
    console.error(`\nERROR: Port ${port} is already in use`);
    console.error(`\nTo fix this:`);
    console.error(`  1. Stop the process using port ${port}`);
    console.error(`  2. Or edit config.json and change the port number`);
    console.error(`  3. Then restart the proxy\n`);
    process.exit(1);
  } else {
    console.error("Server error:", err);
    process.exit(1);
  }
});