[FEAT] Check port access in docker before showing a default error (#961)

* [FEAT] Added port checks in updateENV.validDockerizedUrl to prevent docker from assuming it cannot access localhost URLs

* [CHORE] Updated error message to include Linux URL

* Patch port checking for general loopbacks

* typo

---------

Co-authored-by: timothycarambat <rambat1010@gmail.com>

server/utils/helpers/portAvailabilityChecker.js

@@ -0,0 +1,46 @@
+// Get all loopback addresses that are available for use or binding.
+function getLocalHosts() {
+  const os = require("os");
+  const interfaces = os.networkInterfaces();
+  const results = new Set([undefined, "0.0.0.0"]);
+
+  for (const _interface of Object.values(interfaces)) {
+    for (const config of _interface) {
+      results.add(config.address);
+    }
+  }
+
+  return Array.from(results);
+}
+
+function checkPort(options = {}) {
+  const net = require("net");
+  return new Promise((resolve, reject) => {
+    const server = net.createServer();
+    server.unref();
+    server.on("error", reject);
+
+    server.listen(options, () => {
+      server.close(() => {
+        resolve(true);
+      });
+    });
+  });
+}
+
+async function isPortInUse(port, host) {
+  try {
+    await checkPort({ port, host });
+    return true;
+  } catch (error) {
+    if (!["EADDRNOTAVAIL", "EINVAL"].includes(error.code)) {
+      return false;
+    }
+  }
+  return false;
+}
+
+module.exports = {
+  isPortInUse,
+  getLocalHosts,
+};

server/utils/helpers/updateENV.js

@@ -462,14 +462,28 @@ function isDownloadedModel(input = "") {
   return files.includes(input);
 }
 
-function validDockerizedUrl(input = "") {
+async function validDockerizedUrl(input = "") {
   if (process.env.ANYTHING_LLM_RUNTIME !== "docker") return null;
+
   try {
-    const { hostname } = new URL(input);
-    if (["localhost", "127.0.0.1", "0.0.0.0"].includes(hostname.toLowerCase()))
-      return "Localhost, 127.0.0.1, or 0.0.0.0 origins cannot be reached from inside the AnythingLLM container. Please use host.docker.internal, a real machine ip, or domain to connect to your service.";
-    return null;
-  } catch {}
+    const { isPortInUse, getLocalHosts } = require("./portAvailabilityChecker");
+    const localInterfaces = getLocalHosts();
+    const url = new URL(input);
+    const hostname = url.hostname.toLowerCase();
+    const port = parseInt(url.port, 10);
+
+    // If not a loopback, skip this check.
+    if (!localInterfaces.includes(hostname)) return null;
+    if (isNaN(port)) return "Invalid URL: Port is not specified or invalid";
+
+    const isPortAvailableFromDocker = await isPortInUse(port, hostname);
+    if (isPortAvailableFromDocker)
+      return "Port is not running a reachable service on loopback address from inside the AnythingLLM container. Please use host.docker.internal (for linux use 172.17.0.1), a real machine ip, or domain to connect to your service.";
+  } catch (error) {
+    console.error(error.message);
+    return "An error occurred while validating the URL";
+  }
+
   return null;
 }
 
@@ -504,10 +518,8 @@ async function updateENV(newENVs = {}, force = false, userId = null) {
     const { envKey, checks, postUpdate = [] } = KEY_MAPPING[key];
     const prevValue = process.env[envKey];
     const nextValue = newENVs[key];
-    const errors = checks
-      .map((validityCheck) => validityCheck(nextValue, force))
-      .filter((err) => typeof err === "string");
 
+    const errors = await executeValidationChecks(checks, nextValue, force);
     if (errors.length > 0) {
       error += errors.join("\n");
       break;
@@ -524,6 +536,13 @@ async function updateENV(newENVs = {}, force = false, userId = null) {
   return { newValues, error: error?.length > 0 ? error : false };
 }
 
+async function executeValidationChecks(checks, value, force) {
+  const results = await Promise.all(
+    checks.map((validator) => validator(value, force))
+  );
+  return results.filter((err) => typeof err === "string");
+}
+
 async function logChangesToEventLog(newValues = {}, userId = null) {
   const { EventLogs } = require("../../models/eventLogs");
   const eventMapping = {