epess-web-backend/src/Graphql/graphql.service.ts

import { Inject, Injectable, Logger, UnauthorizedException } from '@nestjs/common'

import { PrismaService } from '../Prisma/prisma.service'
import { Request } from 'express'
import { clerkClient } from '@clerk/express'

import { RedisService } from '../Redis/redis.service'

@Injectable()
export class GraphqlService {
  constructor(
    private readonly prisma: PrismaService,
    @Inject('REDIS_CLIENT') private readonly redis: RedisService,
  ) {}

  async acquireContextFromSessionId(sessionId: string) {
    return this.acquireContext({
      headers: { 'x-session-id': sessionId },
    } as unknown as Request)
  }

  async acquireContext(req: Request) {
    // get x-session-id from headers
    let sessionId: string
    const disableAuth = process.env.DISABLE_AUTH === 'true'
    try {
      sessionId = req.headers['x-session-id'] as string
    } catch (_error) {
      return null
    }
    if (disableAuth) {
      return null
    }
    // check if the sessionId is valid
    if (!sessionId) {
      return null
    }
    // redis context cache
    const cachedUser = await this.redis.getUser(sessionId)
    if (cachedUser) {
      // Logger.log(`Found cached user for sessionId: ${sessionId}`)
      return cachedUser
    }
    // check if the token is valid
    const session = await clerkClient.sessions.getSession(sessionId as string)
    if (!session) {
      throw new UnauthorizedException('Invalid session')
    }
    const user = await this.prisma.user.findUnique({
      where: { id: session.userId },
    })
    if (!user) {
      throw new UnauthorizedException('User not found')
    }
    await this.redis.setUser(sessionId, user, session.expireAt)
    return user
  }

  async invalidateCache(sessionId: string) {
    // invalidate redis cache for sessionId
    await this.redis.del(sessionId)
    Logger.log(`Invalidated cache for sessionId: ${sessionId}`)
  }
}