feat: AI dev stream over HTTPS (SSE read + draft writeback)

Replaces the Redis-over-Tailscale handoff with a far simpler HTTP surface on the existing public API — no Redis client, Tailscale, or firewall changes needed on the dev side. - GET /ai/stream — SSE feed of every ingested message, reads the internal Redis stream; resumes from Last-Event-ID on reconnect (no missed messages); heartbeats keep the connection warm through proxies - POST /ai/drafts — writeback: creates a ContentDraft (PENDING_REVIEW) that shows up in the admin /admin/drafts review UI - AiStreamGuard — static bearer token auth (AI_STREAM_TOKEN), accepts header or ?token= query for browser EventSource - Remove Tailscale sidecar + public Redis port; Redis stays internal-only Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-06-20 13:06:17 +05:30
parent 7cafbc8ba6
commit 530f81416a
8 changed files with 270 additions and 23 deletions
@@ -0,0 +1,40 @@
+import { Controller, Get, Post, Body, Query, Headers, Sse, UseGuards, MessageEvent } from '@nestjs/common';
+import { Observable } from 'rxjs';
+import { Public } from '../auth/public.decorator';
+import { AiStreamGuard } from './ai-stream.guard';
+import { AiStreamService } from './ai-stream.service';
+import { CreateDraftDto } from './dto';
+
+/**
+ * External AI-developer integration surface.
+ *
+ *   GET  /ai/stream   — SSE feed of every ingested message (read)
+ *   POST /ai/drafts   — write back extracted content drafts (write)
+ *
+ * All endpoints are @Public() to bypass the global JWT guard, then protected by
+ * AiStreamGuard (static bearer token). Runs over the existing public HTTPS API,
+ * so no Redis client, Tailscale, or firewall changes are needed on the dev side.
+ */
+@Controller('ai')
+@Public()
+@UseGuards(AiStreamGuard)
+export class AiStreamController {
+  constructor(private readonly service: AiStreamService) {}
+
+  @Sse('stream')
+  stream(
+    @Query('after') after?: string,
+    @Headers('last-event-id') lastEventId?: string,
+  ): Observable<MessageEvent> {
+    // Last-Event-ID (set automatically by EventSource on reconnect) wins so the
+    // client resumes exactly where it dropped. Otherwise honour ?after=, default
+    // to '$' = only new messages from now on.
+    const cursor = lastEventId || after || '$';
+    return this.service.streamMessages(cursor);
+  }
+
+  @Post('drafts')
+  createDraft(@Body() dto: CreateDraftDto): Promise<{ draftId: string }> {
+    return this.service.createDraft(dto);
+  }
+}
@@ -0,0 +1,43 @@
+import { CanActivate, ExecutionContext, Injectable, UnauthorizedException } from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
+import { timingSafeEqual } from 'crypto';
+
+/**
+ * Guard for the AI-dev stream + writeback endpoints.
+ *
+ * Authenticates with a single static bearer token (AI_STREAM_TOKEN), accepted
+ * either as `Authorization: Bearer <token>` (POST / header-capable clients) or
+ * as a `?token=<token>` query param (browser EventSource cannot set headers).
+ *
+ * This is a separate auth realm from the admin/member JWT — the AI dev never
+ * gets a login, just one long-lived token you rotate by changing the env var.
+ */
+@Injectable()
+export class AiStreamGuard implements CanActivate {
+  constructor(private readonly config: ConfigService) {}
+
+  canActivate(context: ExecutionContext): boolean {
+    const expected = this.config.get<string>('AI_STREAM_TOKEN');
+    if (!expected) {
+      throw new UnauthorizedException('AI stream is not configured');
+    }
+
+    const req = context.switchToHttp().getRequest();
+    const header: string | undefined = req.headers?.authorization;
+    const fromHeader = header?.startsWith('Bearer ') ? header.slice(7) : undefined;
+    const fromQuery: string | undefined = req.query?.token;
+    const provided = fromHeader ?? fromQuery;
+
+    if (!provided || !safeEqual(provided, expected)) {
+      throw new UnauthorizedException('Invalid AI stream token');
+    }
+    return true;
+  }
+}
+
+function safeEqual(a: string, b: string): boolean {
+  const ab = Buffer.from(a);
+  const bb = Buffer.from(b);
+  if (ab.length !== bb.length) return false;
+  return timingSafeEqual(ab, bb);
+}
@@ -0,0 +1,9 @@
+import { Module } from '@nestjs/common';
+import { AiStreamController } from './ai-stream.controller';
+import { AiStreamService } from './ai-stream.service';
+
+@Module({
+  controllers: [AiStreamController],
+  providers: [AiStreamService],
+})
+export class AiStreamModule {}
@@ -0,0 +1,150 @@
+import { Injectable, NotFoundException, BadRequestException, Logger } from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
+import { MessageEvent } from '@nestjs/common';
+import { Observable } from 'rxjs';
+import Redis from 'ioredis';
+import { PrismaService } from '../../prisma/prisma.service';
+import { CreateDraftDto } from './dto';
+
+const STREAM_KEY = 'tower:stream:messages';
+// Block this long per XREAD; on timeout we emit a heartbeat to keep the
+// connection warm through proxies, then loop again.
+const BLOCK_MS = 15000;
+
+interface StreamRecord {
+  messageId: string;
+  tenantId: string;
+  content: string;
+  senderJid: string;
+  senderName: string | null;
+  sourceGroupId: string;
+  tags: string[];
+  effectiveAction: string | null;
+  traceId: string | null;
+  timestamp: string;
+}
+
+@Injectable()
+export class AiStreamService {
+  private readonly logger = new Logger(AiStreamService.name);
+  private readonly redisUrl: string;
+
+  constructor(
+    private readonly config: ConfigService,
+    private readonly prisma: PrismaService,
+  ) {
+    this.redisUrl = this.config.get<string>('REDIS_URL', 'redis://localhost:6379');
+  }
+
+  /**
+   * SSE source. Reads the Redis stream from `afterId` and emits one MessageEvent
+   * per message, with the stream entry id set as the SSE event id so the client's
+   * Last-Event-ID resumes exactly where it dropped off.
+   *
+   * afterId semantics (Redis stream cursor):
+   *   '$'  → only messages that arrive after connect (default for a fresh client)
+   *   '0'  → replay the entire retained stream (~50k messages) then follow live
+   *   '<id>' → resume strictly after that entry (used on reconnect)
+   */
+  streamMessages(afterId: string): Observable<MessageEvent> {
+    return new Observable<MessageEvent>((subscriber) => {
+      const redis = new Redis(this.redisUrl, { maxRetriesPerRequest: null });
+      let active = true;
+      let cursor = afterId;
+
+      const loop = async () => {
+        while (active) {
+          try {
+            const res = (await redis.xread(
+              'COUNT', 100,
+              'BLOCK', BLOCK_MS,
+              'STREAMS', STREAM_KEY, cursor,
+            )) as [string, [string, string[]][]][] | null;
+
+            if (!res) {
+              // Idle timeout — heartbeat keeps the pipe alive. EventSource.onmessage
+              // ignores typed events, so this won't reach the dev's message handler.
+              if (active) subscriber.next({ type: 'heartbeat', data: '' } as MessageEvent);
+              continue;
+            }
+
+            for (const [, entries] of res) {
+              for (const [id, fields] of entries) {
+                cursor = id;
+                subscriber.next({ id, data: parseFields(fields) } as MessageEvent);
+              }
+            }
+          } catch (err) {
+            if (active) subscriber.error(err);
+            break;
+          }
+        }
+      };
+
+      loop();
+
+      return () => {
+        active = false;
+        redis.disconnect();
+      };
+    });
+  }
+
+  /**
+   * Writeback: the AI dev posts an extracted draft. Creates a ContentDraft in
+   * PENDING_REVIEW status — it then shows up in the admin /admin/drafts UI for
+   * approve/reject, which publishes the real Event/SevaOpportunity/KnowledgeItem.
+   */
+  async createDraft(dto: CreateDraftDto): Promise<{ draftId: string }> {
+    const message = await this.prisma.message.findUnique({
+      where: { id: dto.sourceMessageId },
+      select: { id: true, tenantId: true },
+    });
+    if (!message) {
+      throw new NotFoundException('sourceMessageId does not exist');
+    }
+    if (message.tenantId !== dto.tenantId) {
+      throw new BadRequestException('tenantId does not match the source message');
+    }
+
+    const draft = await this.prisma.contentDraft.create({
+      data: {
+        tenantId: dto.tenantId,
+        type: dto.type,
+        status: 'PENDING_REVIEW',
+        sourceMessageId: dto.sourceMessageId,
+        proposedJson: dto.proposedJson as object,
+        confidence: dto.confidence ?? null,
+      },
+      select: { id: true },
+    });
+
+    this.logger.log(`AI draft created: ${draft.id} (${dto.type}) from message ${dto.sourceMessageId}`);
+    return { draftId: draft.id };
+  }
+}
+
+function parseFields(fields: string[]): StreamRecord {
+  const obj: Record<string, string> = {};
+  for (let i = 0; i < fields.length; i += 2) {
+    obj[fields[i]] = fields[i + 1];
+  }
+  let tags: string[] = [];
+  try {
+    tags = obj.tags ? JSON.parse(obj.tags) : [];
+  } catch {
+    tags = [];
+  }
+  return {
+    messageId: obj.messageId ?? '',
+    tenantId: obj.tenantId ?? '',
+    content: obj.content ?? '',
+    senderJid: obj.senderJid ?? '',
+    senderName: obj.senderName || null,
+    sourceGroupId: obj.sourceGroupId ?? '',
+    tags,
+    effectiveAction: obj.effectiveAction || null,
+    traceId: obj.traceId || null,
+    timestamp: obj.timestamp ?? '',
+  };
+}
@@ -0,0 +1,24 @@
+import { IsString, IsIn, IsOptional, IsNumber, IsObject, Min, Max } from 'class-validator';
+import { DraftType } from '@prisma/client';
+
+const DRAFT_TYPES: DraftType[] = ['EVENT', 'SEVA_TASK', 'FAQ_ITEM'];
+
+export class CreateDraftDto {
+  @IsString()
+  tenantId!: string;
+
+  @IsString()
+  sourceMessageId!: string;
+
+  @IsIn(DRAFT_TYPES)
+  type!: DraftType;
+
+  @IsObject()
+  proposedJson!: Record<string, unknown>;
+
+  @IsOptional()
+  @IsNumber()
+  @Min(0)
+  @Max(1)
+  confidence?: number;
+}