AuthDirective.ts

import { SchemaDirectiveVisitor } from 'graphql-tools';
import { gql, AuthenticationError } from 'apollo-server';
import { GraphQLField, defaultFieldResolver } from 'graphql';
import AccessTokenModel from '../models/AccessTokenModel';
import { ResolverContext } from '../types';

class AuthDirective extends SchemaDirectiveVisitor {
  visitFieldDefinition(field: GraphQLField<any, any>) {
    const { resolve = defaultFieldResolver } = field;

    field.resolve = async function (...args) {
      const context = args[2] as ResolverContext;

      if (!context.token) {
        throw new AuthenticationError("User authorization failed: no token passed.");
      }

      const token = await AccessTokenModel.findOne({
        token: context.headers.token
      });
  
      if (!token) {
        throw new AuthenticationError("Access denied");
      }

      args[2] = {
        ...context,
        user_id: token.user_id,
        token
      };

      return resolve.apply(this, args);
    };

    field.description =
      (field.description ? field.description + '\n ' : '') +
      '`require authorization`';
  }
}

export default {
  declaration: gql`
    directive @auth on FIELD_DEFINITION
  `,
  directive: AuthDirective
};
    
    
/*
  Usage:
    
   type MessagesMutation {
     send(input: MessageSendInput!): Message! @auth
   }
*/