graphql-auth.guard.ts

import { CanActivate, ExecutionContext, Injectable } from "@nestjs/common";
import { GqlExecutionContext } from "@nestjs/graphql";
import { Request } from "express";
import { Observable } from "rxjs";
import { PrismaService } from "src/prisma/prisma.service";

@Injectable()
export class GraphQLAuthGuard implements CanActivate {

    constructor(private prismaService: PrismaService) {}
    
    async canActivate(context: ExecutionContext): Promise<boolean> {
        const ctx = GqlExecutionContext.create(context);

        const req: Request = ctx.getContext().req;

        const token = req.headers.authorization;

        if (!token)
            return false;

        const group = await this.prismaService.group.findFirst({
            where: { code: token },
        });

        if (!group)
            return false;

        req.group = group;

        return true;
    }

}