shopify-express-x

A small set of abstractions that will help you quickly build an Express.js app that consumes the Shopify API.

Install

yarn add shopify-express-x

Example

const express = require('express');
const shopifyExpress = require('shopify-express-x');
const session = require('express-session');

const app = express();

const {
  SHOPIFY_APP_KEY,
  SHOPIFY_APP_HOST,
  SHOPIFY_APP_SECRET,
  NODE_ENV,
} = process.env;

// session is necessary for api proxy and auth verification
app.use(session({secret: SHOPIFY_APP_SECRET}));

const {routes, withShop} = shopifyExpress({
  host: SHOPIFY_APP_HOST,
  apiKey: SHOPIFY_APP_KEY,
  secret: SHOPIFY_APP_SECRET,
  scope: ['write_orders, write_products'],
  accessMode: 'offline',
  afterAuth(request, response) {
    const { session: { accessToken, shop } } = request;
    // install webhooks or hook into your own app here
    return response.redirect('/');
  },
});

// mounts '/auth' and '/api' off of '/shopify'
app.use('/shopify', routes);

// shields myAppMiddleware from being accessed without session
app.use('/myApp', withShop({authBaseUrl: '/shopify'}), myAppMiddleware)

Shopify routes

  const {routes} = shopifyExpress(config);
  app.use('/', routes);

Provides mountable routes for authentication and API proxying. The authentication endpoint also handles shop session storage using a configurable storage strategy (defaults to SQLite).

/auth/shopify

Serves a login endpoint so merchants can access your app with a shop session.

/api

Proxies requests to the api for the currently logged in shop. Useful to securely use api endpoints from a client application without having to worry about CORS.

shopStore

shopifyExpress's config takes an optional shopStore key, You can use this to define a strategy for how the module will store your persistent data for user sessions.

Strategies

By default the package comes with MemoryStrategy, RedisStrategy, and SqliteStrategy. If none are specified, the default is MemoryStrategy.

MemoryStrategy

Simple javascript object based memory store for development purposes. Do not use this in production!

const shopifyExpress = require('@shopify/shopify-express');
const {MemoryStrategy} = require('@shopify/shopify-express/strategies');

const shopify = shopifyExpress({
  shopStore: new MemoryStrategy(redisConfig),
  ...restOfConfig,
});

RedisStrategy

Uses redis under the hood, so you can pass it any configuration that's valid for the library.

const shopifyExpress = require('@shopify/shopify-express');
const {RedisStrategy} = require('@shopify/shopify-express/strategies');

const redisConfig = {
  // your config here
};

const shopify = shopifyExpress({
  shopStore: new RedisStrategy(redisConfig),
  ...restOfConfig,
});

SQLStrategy

Uses knex under the hood, so you can pass it any configuration that's valid for the library. By default it uses sqlite3 so you'll need to run yarn add sqlite3 to use it. Knex also supports postgreSQL and mySQL.

const shopifyExpress = require('@shopify/shopify-express');
const {SQLStrategy} = require('@shopify/shopify-express/strategies');

// uses sqlite3 if no settings are specified
const knexConfig = {
  // your config here
};

const shopify = shopifyExpress({
  shopStore: new SQLStrategy(knexConfig),
  ...restOfConfig,
});

SQLStrategy expects a table named shops with a primary key id, and string fields for shopify_domain and access_token. It's recommended you index shopify_domain since it is used to look up tokens.

If you do not have a table already created for your store, you can generate one with new SQLStrategy(myConfig).initialize(). This returns a promise so you can finish setting up your app after it if you like, but we suggest you make a separate db initialization script, or keep track of your schema yourself.

Custom Strategy

shopifyExpress accepts any javascript class matching the following interface:

  class Strategy {
    // shop refers to the shop's domain name
    getShop({ shop }): Promise<{accessToken: string}>
    // shop refers to the shop's domain name
    storeShop({ shop, accessToken }): Promise<{accessToken: string}>
  }

Helper middleware

const {middleware: {withShop, withWebhook}} = shopifyExpress(config);

withShop

app.use('/someProtectedPath', withShop({authBaseUrl: '/shopify'}), someHandler);

Express middleware that validates the presence of your shop session. The parameter you pass to it should match the base URL for where you've mounted the shopify routes.

withWebhook

app.use('/someProtectedPath', withWebhook, someHandler);

Express middleware that validates the presence of a valid HMAC signature to allow webhook requests from shopify to your app.

Gotchas

Install route

For the moment the app expects you to mount your install route at /install. See shopify-node-app for details.

Express Session

This library expects express-session or a compatible library to be installed and set up for much of it's functionality. Api Proxy and auth verification functions won't work without something putting a session key on request.

It is possible to use auth without a session key on your request, but not recommended.

Body Parser

This library handles body parsing on it's own for webhooks. If you're using webhooks you should make sure to follow express best-practices by only adding your body parsing middleware to specific routes that need it.

Good

  app.use('/some-route', bodyParser.json(), myHandler);

  app.use('/webhook', withWebhook(myWebhookHandler));
  app.use('/', shopifyExpress.routes);

Bad

  app.use(bodyParser.json());
  app.use('/some-route', myHandler);

  app.use('/webhook', withWebhook(myWebhookHandler));
  app.use('/', shopifyExpress.routes);

Contributing

Contributions are welcome. Please refer to the contributing guide for more details.