WIP: resuming

api/server/routes/agents/index.js

@@ -1,5 +1,6 @@
 const express = require('express');
-const { isEnabled } = require('@librechat/api');
+const { isEnabled, GenerationJobManager } = require('@librechat/api');
+const { logger } = require('@librechat/data-schemas');
 const {
   uaParser,
   checkBan,
@@ -22,6 +23,108 @@ router.use(uaParser);
 
 router.use('/', v1);
 
+/**
+ * Stream endpoints - mounted before chatRouter to bypass rate limiters
+ * These are GET requests and don't need message body validation or rate limiting
+ */
+
+/**
+ * @route GET /chat/stream/:streamId
+ * @desc Subscribe to an ongoing generation job's SSE stream with replay support
+ * @access Private
+ * @description Replays any chunks missed during disconnect, then streams live
+ */
+router.get('/chat/stream/:streamId', (req, res) => {
+  const { streamId } = req.params;
+
+  const job = GenerationJobManager.getJob(streamId);
+  if (!job) {
+    return res.status(404).json({
+      error: 'Stream not found',
+      message: 'The generation job does not exist or has expired.',
+    });
+  }
+
+  res.setHeader('Content-Encoding', 'identity');
+  res.setHeader('Content-Type', 'text/event-stream');
+  res.setHeader('Cache-Control', 'no-cache, no-transform');
+  res.setHeader('Connection', 'keep-alive');
+  res.setHeader('X-Accel-Buffering', 'no');
+  res.flushHeaders();
+
+  logger.debug(`[AgentStream] Client subscribed to ${streamId}`);
+
+  const result = GenerationJobManager.subscribe(
+    streamId,
+    (event) => {
+      if (!res.writableEnded) {
+        res.write(`event: message\ndata: ${JSON.stringify(event)}\n\n`);
+        if (typeof res.flush === 'function') {
+          res.flush();
+        }
+      }
+    },
+    (event) => {
+      if (!res.writableEnded) {
+        res.write(`event: message\ndata: ${JSON.stringify(event)}\n\n`);
+        if (typeof res.flush === 'function') {
+          res.flush();
+        }
+        res.end();
+      }
+    },
+    (error) => {
+      if (!res.writableEnded) {
+        res.write(`event: error\ndata: ${JSON.stringify({ error })}\n\n`);
+        if (typeof res.flush === 'function') {
+          res.flush();
+        }
+        res.end();
+      }
+    },
+  );
+
+  if (!result) {
+    return res.status(404).json({ error: 'Failed to subscribe to stream' });
+  }
+
+  req.on('close', () => {
+    logger.debug(`[AgentStream] Client disconnected from ${streamId}`);
+    result.unsubscribe();
+  });
+});
+
+/**
+ * @route GET /chat/status/:conversationId
+ * @desc Check if there's an active generation job for a conversation
+ * @access Private
+ * @returns { active, streamId, status, chunkCount, aggregatedContent, createdAt }
+ */
+router.get('/chat/status/:conversationId', (req, res) => {
+  const { conversationId } = req.params;
+
+  const job = GenerationJobManager.getJobByConversation(conversationId);
+
+  if (!job) {
+    return res.json({ active: false });
+  }
+
+  if (job.metadata.userId !== req.user.id) {
+    return res.status(403).json({ error: 'Unauthorized' });
+  }
+
+  const info = GenerationJobManager.getStreamInfo(job.streamId);
+
+  res.json({
+    active: info?.active ?? false,
+    streamId: job.streamId,
+    status: info?.status ?? job.status,
+    chunkCount: info?.chunkCount ?? 0,
+    aggregatedContent: info?.aggregatedContent,
+    createdAt: info?.createdAt ?? job.createdAt,
+  });
+});
+
 const chatRouter = express.Router();
 chatRouter.use(configMiddleware);