decolua/9router · critical · Error

MITM server.js not found at ${effectiveServerPath}. Reinstal

Error message

MITM server.js not found at ${effectiveServerPath}. Reinstall 9router.

What it means

Before spawning the MITM worker, startServer verifies SERVER_PATH (the runtime-copied mitm server.js) exists. If missing, it re-copies the bundled copy via ensureRuntimeServer(resolveBundledServerPath()) and re-checks; if the recopy also yields nothing it throws 'MITM server.js not found at <path>. Reinstall 9router.' This means the runtime asset could not be located or restored from the installed package.

Source

Thrown at src/mitm/manager.js:581

      try {
        await installCert(password, rootCACertPath);
        log("🔐 Cert: ✅ trusted");
      } catch (e) {
        throw new Error(`Failed to trust certificate: ${e.message}`);
      }
    }
  } else {
    log("🔐 Cert: already trusted ✅");
  }

  // Step 2: Spawn server (Root CA already installed in Step 1.5)
  // Verify server.js exists — recopy if runtime file was deleted (antivirus/cleanup)
  let effectiveServerPath = SERVER_PATH;
  if (!effectiveServerPath || !fs.existsSync(effectiveServerPath)) {
    log(`[MITM] server.js missing at ${effectiveServerPath} → recopying`);
    effectiveServerPath = ensureRuntimeServer(resolveBundledServerPath());
    if (!effectiveServerPath || !fs.existsSync(effectiveServerPath)) {
      throw new Error(`MITM server.js not found at ${effectiveServerPath}. Reinstall 9router.`);
    }
  }
  const mitmRouterBase = await resolveMitmRouterBaseUrl();
  log(`🚀 Starting server... (router: ${mitmRouterBase})`);
  if (IS_WIN) {
    // Check port 443 — ask user before killing
    const winOwner = await getPort443Owner(sudoPassword);
    if (winOwner) {
      if (forceKillPort443) {
        log(`Killing process on port 443 (PID ${winOwner.pid}, name=${winOwner.name})...`);
        await killPort443Owner(winOwner, sudoPassword);
      } else {
        const e = new Error(`Port 443 is already in use by "${winOwner.name}" (PID ${winOwner.pid}).`);
        e.code = "PORT_443_BUSY";
        e.portOwner = { pid: winOwner.pid, name: winOwner.name };
        throw e;
      }
    }

View on GitHub (pinned to 90b52e06ff)

Solutions

Reinstall the package: `npm install -g 9router` (or re-run the CLI installer) so the bundled server asset is restored
Check whether AV quarantined the file and whitelist ~/.9router (and the package install dir) before reinstalling
Verify the runtime dir contents — delete the MITM runtime folder under ~/.9router so the next start recopies everything fresh from the bundle
If developing locally, run the build/bundle step that emits the MITM server asset and confirm resolveBundledServerPath() points at an existing file

Example fix

// after reinstalling, force a clean recopy
rm -rf ~/.9router/mitm && npx 9router start
// or in code, verify before starting
if (!fs.existsSync(serverPath)) await reinstall9router(); // before startServer(apiKey)

Defensive patterns

Strategy: validation

Validate before calling

const fs = require('fs');
const path = require('path');
function assertMitmRuntimePresent() {
  const mitmDir = require('os').homedir() + '/.9router/mitm';
  const serverPath = path.join(mitmDir, 'server.js');
  if (!fs.existsSync(serverPath)) {
    throw new Error(`MITM runtime missing at ${serverPath} — reinstall 9router before starting the proxy.`);
  }
  return serverPath;
}

Try / catch

try {
  await startServer(apiKey);
} catch (e) {
  if (/MITM server\.js not found/.test(e.message)) {
    console.error('Runtime files missing — reinstalling 9router is required:', e.message);
    // do NOT retry; surface an actionable reinstall step to the user
  } else throw e;
}

Prevention

Whitelist ~/.9router and the global npm install dir in antivirus/EDR software
After any version upgrade, verify the runtime server.js exists before starting
Reinstall via npm rather than copying files by hand so bundled assets land correctly
In CI/Docker, bake the runtime copy into the image instead of relying on first-start recopy

When it happens

Trigger: SERVER_PATH unset or the runtime file deleted (antivirus quarantine, disk cleanup) AND resolveBundledServerPath() returns null/empty or a non-existent path — e.g. running from a source checkout without the bundled asset, a broken/partial npm install, or a package layout change where the bundled server.js isn't where expected.

Common situations: Windows Defender or corporate AV quarantining mitm server.js repeatedly (this is exactly the recopy path's reason for existing); installing via a truncated npm cache or partial download; running cli/ from a dev clone where the bundling step that places the asset wasn't run; upgrading versions with a stale half-deleted runtime directory under ~/.9router.

Related errors

AI-assisted analysis of decolua/9router@90b52e06ff (2026-08-30). Data as JSON: /api/errors/0249ea9e235fd6df. Report an issue: GitHub.