🔉 feat: TTS/STT rate limiters (#2925)

* fix: remove double initialization of speech routes

* refactor(useMessageHelpers): more consistent latestMessage updates based on unique textKey and early returns when setting

* feat: TTS/STT rate limiters

* chore: remove console log

* fix: make modular chat true by default

api/server/middleware/speech/sttLimiters.js

@@ -0,0 +1,68 @@
+const rateLimit = require('express-rate-limit');
+const { ViolationTypes } = require('librechat-data-provider');
+const logViolation = require('~/cache/logViolation');
+
+const getEnvironmentVariables = () => {
+  const STT_IP_MAX = parseInt(process.env.STT_IP_MAX) || 100;
+  const STT_IP_WINDOW = parseInt(process.env.STT_IP_WINDOW) || 1;
+  const STT_USER_MAX = parseInt(process.env.STT_USER_MAX) || 50;
+  const STT_USER_WINDOW = parseInt(process.env.STT_USER_WINDOW) || 1;
+
+  const sttIpWindowMs = STT_IP_WINDOW * 60 * 1000;
+  const sttIpMax = STT_IP_MAX;
+  const sttIpWindowInMinutes = sttIpWindowMs / 60000;
+
+  const sttUserWindowMs = STT_USER_WINDOW * 60 * 1000;
+  const sttUserMax = STT_USER_MAX;
+  const sttUserWindowInMinutes = sttUserWindowMs / 60000;
+
+  return {
+    sttIpWindowMs,
+    sttIpMax,
+    sttIpWindowInMinutes,
+    sttUserWindowMs,
+    sttUserMax,
+    sttUserWindowInMinutes,
+  };
+};
+
+const createSTTHandler = (ip = true) => {
+  const { sttIpMax, sttIpWindowInMinutes, sttUserMax, sttUserWindowInMinutes } =
+    getEnvironmentVariables();
+
+  return async (req, res) => {
+    const type = ViolationTypes.STT_LIMIT;
+    const errorMessage = {
+      type,
+      max: ip ? sttIpMax : sttUserMax,
+      limiter: ip ? 'ip' : 'user',
+      windowInMinutes: ip ? sttIpWindowInMinutes : sttUserWindowInMinutes,
+    };
+
+    await logViolation(req, res, type, errorMessage);
+    res.status(429).json({ message: 'Too many STT requests. Try again later' });
+  };
+};
+
+const createSTTLimiters = () => {
+  const { sttIpWindowMs, sttIpMax, sttUserWindowMs, sttUserMax } = getEnvironmentVariables();
+
+  const sttIpLimiter = rateLimit({
+    windowMs: sttIpWindowMs,
+    max: sttIpMax,
+    handler: createSTTHandler(),
+  });
+
+  const sttUserLimiter = rateLimit({
+    windowMs: sttUserWindowMs,
+    max: sttUserMax,
+    handler: createSTTHandler(false),
+    keyGenerator: function (req) {
+      return req.user?.id; // Use the user ID or NULL if not available
+    },
+  });
+
+  return { sttIpLimiter, sttUserLimiter };
+};
+
+module.exports = createSTTLimiters;