How to validate the whole input object?

[AhmedBHameed]

Hi

Reading about graphql validation and want to build custom directive to validate input types in apollo server. The reason behind is to use joi library as a validation since it is more flexible and rich with validations.

I've done the following:

auth.directive.ts (Ignore the implementation since it is not the issue here)

import { mapSchema, MapperKind } from "@graphql-tools/utils";
import { GraphQLSchema } from "graphql";

const validateDirective = (directiveName: string) => {
  return {
    validateDirectiveTypeDefs: `directive @${directiveName} on INPUT_OBJECT_FIELD`,
    validateDirectiveTransformer: (schema: GraphQLSchema) =>
      mapSchema(schema, {
        [MapperKind.INPUT_OBJECT_FIELD]: (
          fieldConfig,
          _fieldName,
          typeName
        ) => {
          console.log(fieldConfig, _fieldName, typeName);
          return fieldConfig;
        },
      }),
  };
};

export const { validateDirectiveTypeDefs, validateDirectiveTransformer } =
  validateDirective("validateAuthInput");

auth.typedef.ts

import { gql } from "apollo-server-core";
import { validateDirectiveTypeDefs } from "./auth.directive";

const AUTH_TYPE = gql`
  ${validateDirectiveTypeDefs}

  """
  Authentication input model
  """
  input AuthInput @validateAuthInput {
    email: String
    password: String
  }

  """
  Authentication data model
  """
  type Auth {
    accessToken: String!
    refreshToken: String!
    userRole: String
  }
`;

export default AUTH_TYPE;

Schema

import { gql } from "apollo-server-express";
import {
  AuthResolvers,
  AUTH_TYPE,
  UserResolvers,
  USER_TYPE,
} from "./resolvers";
import { validateDirectiveTransformer } from "./resolvers/auth/auth.directive";
import { makeExecutableSchema } from "@graphql-tools/schema";

const typeDefs = gql`
  """
  \`ISO 8601\` date format. E.g: 2021-08-09T09:45:16.696Z
  """
  scalar Date

  ${USER_TYPE}

  ${AUTH_TYPE}

  type Message {
    message: String
    string: String @deprecated(reason: "Use message field instead.")
    date: Date
  }

  type Query {
    """
    Generate tokens.
    """
    tokens(userData: AuthInput!): Auth

    """
    Simple query for demonstration purposes.
    """
    sayHi: Message

    """
    Fetch all articles
    """
    getAllUsers: [User]
  }

  # MUTATIONS
  # type Mutation {}
`;

const executableSchema = makeExecutableSchema({
  typeDefs,
  resolvers: [UserResolvers, AuthResolvers],
});

const schemaWithAuthValidation = validateDirectiveTransformer(executableSchema);

export default schemaWithAuthValidation;

I'm getting the following error

error: GraphQLError [Object]: Syntax Error: Unexpected Name "INPUT_OBJECT_FIELD

Any idea if this is possbile?

[ardatan]

It seems you are using directive validateAuthInput for input types not fields. So it should be something like INPUT_OBJECT. And this error seems related to GraphQLJS parser that says there is no identifier like INPUT_OBJECT_FIELD.

Other than that, I'd use scalars for this kind of validation instead of directives which would be waay easier to implement and maintain.

[AhmedBHameed]

@ardatan thank you for the rapid support.

INPUT_OBJECT resolved the error, however, I'm not sure if my implementation is right because when the server start, it runs the directive immediately!! Any future query bypass the validation :(

I'm sure the issue is lack of information so hopefully you can lighten me.

[ardatan]

Because you need the validation inside resolver and you need to wrap the field of the object type that uses your input type as one of the arguments :)
That's why I suggested you to use scalars not directives.

[AhmedBHameed]

Fair enough!
Dropping down my implementation.

@ardatan Thank you for your kind support.
Feel free closing this issue.

[yaacovCR]

See also #3337 (reply in thread)