Securing GraphQL API

Overview

At the moment, all car manufacturers-related queries and mutations that we’ve added to our GraphQL API are publicly exposed.

For example, if were to perform a simple listCarManufacturers GraphQL query, we would receive a list of all car manufacturers:

Exposed GraphQL Queries

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Even more important, anybody can create new car manufacturers, with the createCarManufacturer GraphQL mutation:

Exposed GraphQL Mutations

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In most cases, this is not the desirable behavior, and you’ll certainly want to have control over who can perform these GraphQL operations, and who cannot.

Securing GraphQL API Resolvers

All of the GraphQL resolver functions are located in the api/code/graphql/src/plugins/scaffolds/carManufacturers/resolvers folder:

.
├── __tests__
├── entities
├── index.ts
├── resolvers
│   ├── CarManufacturersMutation.ts
│   ├── CarManufacturersQuery.ts
│   ├── CarManufacturersResolver.ts
│   └── index.ts
├── typeDefs.ts
└── types.ts

For purposes of this tutorial, let’s open the simplest resolver function, which is the getCarManufacturer , and add the following lines of code (parts removed for brevity):

import { CarManufacturerEntity, CarManufacturersPermission } from "../types";
import { CarManufacturer } from "../entities";
import CarManufacturersResolver from "./CarManufacturersResolver";

// We use this when specifying the return types of the getPermission function call (below).
import { FullAccessPermission } from "@webiny/api-security/types";

(...)

/**
 * To define our GraphQL resolvers, we are using the "class method resolvers" approach.
 * https://www.graphql-tools.com/docs/resolvers#class-method-resolvers
 */
export default class CarManufacturersQueryResolver extends CarManufacturersResolver
    implements CarManufacturersQuery {
    /**
     * Returns a single CarManufacturer entry from the database.
     * @param id
     */
     async getCarManufacturer({ id }: GetCarManufacturerParams) {
        // First, check if the current identity can perform the "getCarManufacturer" query,
        // within the detected locale. An error will be thrown if access is not allowed.
        const hasLocaleAccess = await this.context.i18nContent.hasI18NContentPermission();
        if (!hasLocaleAccess) {
            throw new Error("Not authorized.");
        }

        // Next, check if the current identity possesses the "car-manufacturers" permission.
        // Note that, if the identity has full access, "FullAccessPermission" permission
        // will be returned instead, which is equal to: { name: "*"}.
        const permission = await this.context.security.getPermission<
            CarManufacturersPermission | FullAccessPermission
        >("car-manufacturers");

        if (!permission) {
            throw new Error("Not authorized.");
        }

        // Note that the received permission object can also be `{ name: "*" }`. If so, that
        // means we are dealing with the super admin, who has unlimited access.
        let hasAccess = permission.name === "*";
        if (!hasAccess) {
            // If not super admin, let's check if we have the "r" in the `rwd` property.
            hasAccess =
                permission.name === "car-manufacturers" &&
                permission.rwd &&
                permission.rwd.includes("r");
        }

        // Finally, if current identity doesn't have access, we immediately exit.
        if (!hasAccess) {
            throw new Error("Not authorized.");
        }

        // Query the database and return the entry. If entry was not found, an error is thrown.
        const { Item: carManufacturer } = await CarManufacturer.get({ PK: this.getPK(), SK: id });
        if (!carManufacturer) {
            throw new Error(`CarManufacturer "${id}" not found.`);
        }

        return carManufacturer;
    }

    (...)
}

yarn webiny watch api/code/graphql --env dev

Now, to see this new piece of authorization logic in action, we can use a GraphQL client, for example the GraphQL Playground , point it to our GraphQL API’s URL, and try executing the following query:

{
  carManufacturers {
    # Replace the `id` with the value that exists in your system.
    getCarManufacturer(id: "60ed25da4a608300054b46b5") {
      id
      title
    }
  }
}

Without including the appropriate Authorization request header, we should receive the following error response:

GraphQL Authorization Error

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If you’ve received the Not authorized. error, that means authorization was successful.

On the other hand, if a valid Authorization request header is included, or in other words, the current identity actually has access to the Car Manufacturers module, the data should be returned.

To manually test that, we can simply create a new user via the Webiny Security application, and either place it into the default Full Access security group, or even better, into the newly created Car Manufacturers security group. Which is what the following screenshot is showing:

Create a Test User

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Once we’ve created the user, we can log in into the Admin Area application with it (using its username and password), and execute the same GraphQL query, this time using the built-in API Playground. We will use this client simply because of the fact that, upon issuing GraphQL operations, it will automatically attach the correct Authorization request header for us. In other words, it will perform GraphQL operations as the currently logged-in user.

So, as we can see in the following screenshot, the GraphQL query was successful, as we’ve successfully received the car manufacturer data in the response:

GraphQL Authorization Success

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This means that the user we’re currently logged-in with has the appropriate security permissions, and that the newly added authorization code works as expected.

Final Notes

Before we wrap this up, note that this is just a single resolver we secured, and that you should implement the same logic into others as well.

Also, in case you start seeing yourself copying some of the authorization related code, it’s certainly recommended that you extract it into one or more separate utility functions. This way we’re not repeating our selves (DRY ) and our code will be easier to maintain.

FAQ

I'm Not Building a Multi-Locale Admin Area Application Module.

If you’re not building a multi-locale Admin Area application module, feel free to skip the await context.i18nContent.hasI18NContentPermission(); checks in your GraphQL resolvers and simply start with your own authorization checks.

But of course, be aware that if your project ends up being multi-locale, then users will be able to execute GraphQL operations in every created locale. At that point, you will most probably want to bring back the removed locale-related authorization checks.