Shopify app frontends 

Gadget provides a rich set of tools for quickly building frontends for Shopify Apps. Each Gadget app connected to Shopify gets a basic, hosted frontend powered by Vite out of the box that already supports OAuth, Shopify's Polaris design system, multi-tenant data security, and Shopify's App Bridge for embedded applications. You can customize this frontend to your liking, or you can build your own external frontend from scratch using Gadget's React packages.

Frontends for Shopify apps communicate with Gadget backends using your Gadget app's GraphQL API and the associated JS client for your application. There are a few different npm packages necessary for working with Gadget from a Shopify app frontend:

Gadget installs these packages into your Gadget-hosted frontend automatically, but if you're building an external frontend you must install them yourself.

Building Shopify apps 

Once you've set up your Shopify Connection, your Gadget app will have a built-in frontend ready for construction in your app's frontend folder. This frontend can access data from your backend, including both models synced from Shopify and models created within your application. By default, your app uses React and Shopify's standard @shopify/app-bridge-react library, so Shopify's normal helpers for navigation and data fetching are ready for use as well.

Gadget frontends for Shopify include Shopify's design system Polaris via the @shopify/polaris package as well, so your app is compliant with Shopify's App Store guidelines out of the box.

If you'd like to build your frontend outside of Gadget, refer to the External Frontends guide.

Reading data from your backend 

Data from your Gadget application, including the non-rate-limited copies of Shopify models and your own created models, can be accessed easily from the frontend using the @gadgetinc/react hooks library. This library provides hooks like useFindOne, useFindMany, useFindFirst for fetching data from your Gadget app.

Each of these hooks returns an object with the requested data, the fetching state, and an error if one was encountered, as well as a refetch function for refreshing the data if need be.

For example, if you have the Shopify Product model enabled in your Connection, we can fetch product records in a variety of ways:

jsx
Copy
1// fetch one product by id
2const [{ data, fetching, error }, refetch] = useFindOne(api.shopifyProduct, 10);
3
4// fetch the first 10 products
5const [{ data, fetching, error }, refetch] = useFindMany(api.shopifyProduct, { first: 10 });
6
7// fetch the first product with the title field equal to "Socks", throw if it isn't found
8const [{ data, fetching, error }, refetch] = useFindFirst(api.shopifyProduct, { where: { title: "Socks" } });
9
10// fetch the first product with the title field equal to "Socks", return null if it isn't found
11const [{ data, fetching, error }, refetch] = useMaybeFindFirst(api.shopifyProduct, { where: { title: "Socks" } });

Data from other models that you've created in your application is accessed the same way. For example, if we're building a free shipping banner app, you might create a Banner model that stores details about each shipping banner created. We can fetch banner records with the same React hooks:

jsx
Copy
// fetch one banner by id
const [{ data, fetching, error }, refetch] = useFindOne(api.banner, 10);

// fetch the first 10 banners
const [{ data, fetching, error }, refetch] = useFindMany(api.banner, { first: 10 });

Each of these hooks must be wrapped in a React component to render. For example, we can use useFindMany to display a list of products in a component:

jsx
Copy
1import { useFindMany } from "@gadgetinc/react";
2import { api } from "../api";
3
4export const ProductsList = (props) => {
5  const [{ data, fetching, error }, _refetch] = useFindMany(api.shopifyProduct, { first: 10 });
6
7  if (fetching) {
8    return <div>Loading...</div>;
9  }
10
11  if (error) {
12    return <div>Error: {error.message}</div>;
13  }
14
15  return <ul>
16    {data.map((product) => <li key={product.id}>{product.title}</li>)}
17  </li>
18}

For more on reading data in the frontend, see the Building Frontends guide and the@gadgetinc/react Readme.

Shopify permissions 

By default, Gadget implements multi-tenant data permissions for your application. An app loaded for one Shopify shop is only able to access data from within that shop, and is not permitted to access data for other shops. This is the default setup that uses the Shopify App User role, and can be customized by editing the permissions for this role on the Roles & Permissions page.

Gadget enforces multi-tenant data permissions for the Shopify models by default, and does not grant automatic access to your own models. To grant the frontend access to your models, add permissions to the Shopify App User role for each model you'd like to access. For example, if you'd like to access a model named Banner, check the Read permission checkbox in the Roles & Permissions screen.

For more information, see the Access Control guide.

Writing data back to your backend 

Shopify app frontends can use the useAction and useGlobalAction hooks from the @gadgetinc/react hooks library to write data back to your database.

To write data back to your database for models you've created, or fields you've added to Shopify Models, use the useAction or useGlobalAction hook in a React component.

For example, if we create a new model within our app called Banner, we can use the useAction hook to create a new banner record:

jsx
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1import { useAction } from "@gadgetinc/react";
2import { api } from "../api";
3
4export const CreateBannerForm = (props) => {
5  const [message, setMessage] = useState("");
6  const [{ data, fetching, error }, act] = useAction(api.banner.create);
7
8  if (fetching) {
9    return <div>Saving...</div>;
10  }
11
12  if (error) {
13    return <div>Error: {error.message}</div>;
14  }
15
16  return (
17    <form
18      onSubmit={() => {
19        // run the action function when the form is submitted
20        // the component will re-render with `fetching: true` initially, and then when the response arrives, render again with the result in `data`.
21        void act({ message });
22      }}
23    >
24      <label>Message</label>
25      <textarea onChange={(e) => setMessage(e.target.value)}>{message}</textarea>
26      <input type="submit" />
27    </form>
28  );
29};

For more details on the useAction hook, see the @gadgetinc/react Readme, and see the Building Frontends guide for more examples.

Calling Global Actions 

Shopify app frontends can call your backend's Global Actions with the useGlobalAction hook. See the Building Frontends guide for more information.

Calling HTTP routes 

Shopify app frontends can call your backend's HTTP Routes with api.fetch, or any other HTTP client for React. See the Building Frontends guide for more information.

Calling the Shopify API 

Gadget generally recommends reading data through Gadget, as Gadget's API doesn't restrict access to data in the same way that Shopify's API does. Your app's Gadget API is not rate-limited, so you don't have to carefully manage requests like you might with Shopify. However, if you need to access data that your app doesn't sync, or if you need to access data that Gadget doesn't have access to, you can use Shopify's API directly.

Shopify supports making requests to the Admin API from the backend of your API best. So, to call Shopify, you make a call from your frontend application to your Gadget backend, and then your Gadget backend calls the Shopify API, and returns results to your frontend.

There's two easy ways to set this up in Gadget: Actions if you want to write data, or HTTP routes if you just want to read data.

Calling Shopify within Actions 

Effect code within Actions or Global Actions can make API calls to Shopify using the connections.shopify.current Shopify API client Gadget provides.

For example, if we want to create a product from the frontend of our Gadget application, we can create an Global Action that calls the Shopify API:

First, we create a new Global Action called createProduct within the Global Actions section of the Gadget editor.

Then, we can add the following code to the Global Action's effect:

global/createProduct/onCreateProduct.js
JavaScript
Copy
1module.exports = async ({ scope, logger, params, connections }) => {
2  const shopify = connections.shopify.current;
3  const product = await shopify.product.create({
4    title: "test 123",
5  });
6  logger.info({ product }, "created new product in shopify");
7  scope.result = product;
8};

This effect uses Gadget's connections object to access the Shopify API client, and then calls the product.create method to create a new product in Shopify.

We can then call this global action from our Shopify frontend with the useGlobalAction React hook. For example, we can call this action when a button is clicked in the app:

frontend/components/CreateProductButton.js
jsx
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1import { useGlobalAction } from "@gadgetinc/react";
2import { api } from "../api";
3
4export const CreateProductButton = (props) => {
5  const [{ data, fetching, error }, act] = useGlobalAction(api.createProduct);
6
7  return (
8    <button disabled={fetching} onClick={() => void act()}>
9      Create Product
10    </button>
11  );
12};

Calling Shopify in HTTP Routes 

Route code within HTTP Routes can access the Shopify API using request.connections.shopify to create a Shopify API client object, similarly to Actions or Global Actions.

For example, an HTTP route could return an up-to-date list of products from the Shopify API:

JavaScript
Copy
1module.exports = async (request, reply) => {
2  const shopify = request.connections.shopify.current;
3  const products = await shopify.product.list();
4  reply.send({
5    products,
6  });
7};

Standalone Shopify Apps 

If your Shopify app is not an embedded app, you can still use the Gadget frontends to build your app. To do so, you will need to set the type prop on GadgetProvider to AppType.Standalone.

<GadgetProvider type={AppType.Standalone} shopifyApiKey={window.gadgetConfig.apiKeys.shopify} api={api} router={appBridgeRouter}>
  <AuthenticatedApp />
</GadgetProvider>

Next is to update your routes/shopify/GET-install.js route file to redirect users back to your frontend instead of the Shopify admin.

1// replace the following
2// if (embedded) {
3//   return await reply.redirect("/?" + new URLSearchParams(query).toString());
4// } else {
5//   const host = Buffer.from(base64Host, 'base64').toString('ascii');
6//   return await reply.redirect(`https://${host}/apps/${apiKey}`);
7// }
8
9return await reply.redirect("/");

This will ensure that once a shop install has completed users will be redirected to your frontend.

Shopify frontend security requirements 

Shopify requires app developers to meet a set of important security requirements when building embedded apps. Gadget meets each security requirement out of the box:

• Gadget apps are always served over HTTPS
• Gadget apps run behind a production-grade firewall and only expose the necessary services
• Gadget apps use robust, multi-tenant authentication that limits access to data to the current shop (see the Access Control guide)
• Gadget sets up GDPR webhook listeners automatically for Shopify apps (see the GDPR docs)
• Gadget uses Shopfiy's Session Token authentication mechanism for authenticating the frontend to the backend.
• Gadget automatically sets the Content-Security-Policy header necessary for Shopify's IFrame protection when serving Shopify apps (see Shopify's security docs)

If you have any questions about the security posture of Gadget applications for Shopify, please join us in our Discord to discuss!

Reference 

The Provider 

The @gadgetinc/react-shopify-app-bridge library handles authentication of your embedded app via the Provider component. This provider has two main benefits - it handles authentication and the series of redirects required to complete an embedded app OAuth flow in Shopify, and it handles retrieving a Shopify session token from the App Bridge and passing it along to Gadget for authenticated calls.

The Provider has the following required props:

export interface ProviderProps {
  type: AppType; // 'AppType.Embedded' or 'AppType.Standalone'
  shopifyApiKey: string; // the API key from your Shopify app in the partner dashboard that is used with the Shopify App Bridge
  api: string; // the API client created using your Gadget application
}

The Gadget provider will handle detecting if your app is being rendered in an embedded context and redirect the user through Shopify's OAuth flow if necessary.

The useGadget React hook 

The Provider handles initializing the App Bridge for us. Now we can build our application component and use the initialized instance of App Bridge via the appBridge key returned from the embedded React hook useGadget.

useGadget provides the following properties:

1export interface useGadget {
2  isAuthenticated: boolean; // 'true' if the user has completed a successful OAuth flow
3  isEmbedded: boolean; // 'true' if the app is running in an embedded context
4  isRootFrameRequest: boolean; // 'true' if a user is viewing a "type: AppType.Embedded" app in a non-embedded context, for example, accessing the app at a hosted Vercel domain
5  loading: boolean; // 'true' if the OAuth flow is in process
6  appBridge: AppBridge; // a ready-to-use app bridge from Shopify, you can also use the traditional useAppBridge hook in your components to retrieve it.
7}

useGadget example 

The following example renders a ProductManager component that makes use of Shopify App Bridge components and is ready to be embedded in a Shopify Admin page.

1import { useAction, useFindMany } from "@gadgetinc/react";
2import { useGadget } from "@gadgetinc/react-shopify-app-bridge";
3import { Button, Redirect, TitleBar } from "@shopify/app-bridge/actions";
4import { api } from "./api.ts";
5
6function ProductManager() {
7  const { loading, appBridge, isRootFrameRequest } = useGadget();
8  const [_, deleteProduct] = useAction(api.shopifyProduct.delete);
9  const [{ data, fetching, error }, refresh] = useFindMany(api.shopifyProduct);
10
11  if (error) return <>Error: {error.toString()}</>;
12  if (fetching) return <>Fetching...</>;
13  if (!data) return <>No widgets found</>;
14
15  // Set up a title bar for the embedded app
16  const breadcrumb = Button.create(appBridge, { label: "My breadcrumb" });
17  breadcrumb.subscribe(Button.Action.CLICK, () => {
18    appBridge.dispatch(Redirect.toApp({ path: "/breadcrumb-link" }));
19  });
20
21  const titleBarOptions = {
22    title: "My page title",
23    breadcrumbs: breadcrumb,
24  };
25  TitleBar.create(appBridge, titleBarOptions);
26
27  return (
28    <>
29      {loading && <span>Loading...</span>}
30      {isRootFrameRequest && (
31        <span>App can only be viewed in the Shopify Admin!</span>
32      )}
33      {!loading &&
34        !isRootFrameRequest &&
35        data.map((widget, i) => (
36          <button
37            key={i}
38            onClick={(event) => {
39              event.preventDefault();
40              void deleteProduct({ id: widget.id }).then(() => refresh());
41            }}
42          >
43            Delete {widget.title}
44          </button>
45        ))}
46    </>
47  );
48}

GraphQL queries 

When building embedded Shopify apps, there may be instances where a Shop's installed scopes have not been updated to match the required scopes in your Gadget app's connection. In these situations, it is necessary to re-authenticate with Shopify so that the app can acquire the updated scopes. The following GraphQL query can be run using the app client (passed to the Provider) and provides information related to missing scopes and whether a re-authentication is necessary.

1query {
2  shopifyConnection {
3    requiresReauthentication
4    missingScopes
5  }
6}

Session model management 

The Shopify Connection in Gadget automatically manages records of the backend Session model when using @gadgetinc/react-shopify-app-bridge. When a merchant first loads up the frontend application, the <Provider/> will retrieve a Shopify Session Token from Shopify's API, and pass it to your Gadget backend application. The Gadget Shopify Connection will then validate this token. If valid, the connection will provision a new record of the Session model with the correct shopId field set up. This session is then passed to all your backend application's model filters and is available within Action code snippets.

Embedded app examples 

Want to see an example of an embedded Shopify app built using Gadget?

Check out some of our example apps on GitHub, including:

• an embedded NextJS application
• an embedded app built using the Shopify CLI