🔉 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/ttsLimiters.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 TTS_IP_MAX = parseInt(process.env.TTS_IP_MAX) || 100;
+  const TTS_IP_WINDOW = parseInt(process.env.TTS_IP_WINDOW) || 1;
+  const TTS_USER_MAX = parseInt(process.env.TTS_USER_MAX) || 50;
+  const TTS_USER_WINDOW = parseInt(process.env.TTS_USER_WINDOW) || 1;
+
+  const ttsIpWindowMs = TTS_IP_WINDOW * 60 * 1000;
+  const ttsIpMax = TTS_IP_MAX;
+  const ttsIpWindowInMinutes = ttsIpWindowMs / 60000;
+
+  const ttsUserWindowMs = TTS_USER_WINDOW * 60 * 1000;
+  const ttsUserMax = TTS_USER_MAX;
+  const ttsUserWindowInMinutes = ttsUserWindowMs / 60000;
+
+  return {
+    ttsIpWindowMs,
+    ttsIpMax,
+    ttsIpWindowInMinutes,
+    ttsUserWindowMs,
+    ttsUserMax,
+    ttsUserWindowInMinutes,
+  };
+};
+
+const createTTSHandler = (ip = true) => {
+  const { ttsIpMax, ttsIpWindowInMinutes, ttsUserMax, ttsUserWindowInMinutes } =
+    getEnvironmentVariables();
+
+  return async (req, res) => {
+    const type = ViolationTypes.TTS_LIMIT;
+    const errorMessage = {
+      type,
+      max: ip ? ttsIpMax : ttsUserMax,
+      limiter: ip ? 'ip' : 'user',
+      windowInMinutes: ip ? ttsIpWindowInMinutes : ttsUserWindowInMinutes,
+    };
+
+    await logViolation(req, res, type, errorMessage);
+    res.status(429).json({ message: 'Too many TTS requests. Try again later' });
+  };
+};
+
+const createTTSLimiters = () => {
+  const { ttsIpWindowMs, ttsIpMax, ttsUserWindowMs, ttsUserMax } = getEnvironmentVariables();
+
+  const ttsIpLimiter = rateLimit({
+    windowMs: ttsIpWindowMs,
+    max: ttsIpMax,
+    handler: createTTSHandler(),
+  });
+
+  const ttsUserLimiter = rateLimit({
+    windowMs: ttsUserWindowMs,
+    max: ttsUserMax,
+    handler: createTTSHandler(false),
+    keyGenerator: function (req) {
+      return req.user?.id; // Use the user ID or NULL if not available
+    },
+  });
+
+  return { ttsIpLimiter, ttsUserLimiter };
+};
+
+module.exports = createTTSLimiters;