PR Feedback

1. Correct typo
2. Change utility name "getHostAppUrl" to "getEmbeddedAppUrl", which is much nicer.
3. Add / to the host in our test.  This matches the format of the host that Shopify provides
4. Flesh out the docs a little more.

docs/usage/utils.md

@@ -1,12 +1,14 @@
 # utils
 
-## Get the HOST application URL using `getHostAppUrl`
+## Get the application URL for embedded apps using `getEmbeddedAppUrl`
 
-If you need to redirect a request to your app inside the user's admin you can use `getHostAppUrl`.
+If you need to redirect a request to your embedded app URL you can use `getEmbeddedAppUrl`
 
 ```ts
-const redirectURL = getHostAppUrl(request);
+const redirectURL = getEmbeddedAppUrl(request);
 res.redirect(redirectURL);
 ```
 
+Using this utility ensures that embedded app URL is properly constructed and brings the merchant to the right place.  It is more reliable than using the shop param.
+
 This utility relies on the host query param being a Base 64 encoded string. All requests from Shopify should include this param in the correct format.

src/utils/__tests__/get-embedded-app-url.test.ts

@@ -0,0 +1,51 @@
+import http from 'http';
+
+import getEmbeddedAppUrl from '../get-embedded-app-url';
+import * as ShopifyErrors from '../../error';
+import {Context} from '../../context';
+
+describe('getEmbeddedAppUrl', () => {
+  beforeEach(() => {
+    Context.API_KEY = 'my-api-key';
+  });
+
+  test('throws an error when no request is passed', () => {
+    // @ts-expect-error: For JS users test it throws when no request is passed
+    expect(() => getEmbeddedAppUrl()).toThrow(
+      ShopifyErrors.MissingRequiredArgument,
+    );
+  });
+
+  test('throws an error when the request has no URL', () => {
+    const req = {
+      url: undefined,
+    } as http.IncomingMessage;
+
+    expect(() => getEmbeddedAppUrl(req)).toThrow(
+      ShopifyErrors.InvalidRequestError,
+    );
+  });
+
+  test('throws an error when the request has no host query param', () => {
+    const req = {
+      url: 'http://www.example.com',
+    } as http.IncomingMessage;
+
+    expect(() => getEmbeddedAppUrl(req)).toThrow(
+      ShopifyErrors.InvalidRequestError,
+    );
+  });
+
+  test('returns the host app url', () => {
+    const host = 'my-store.shopify.com/admin';
+    const base64Host = Buffer.from(host, 'utf-8').toString('base64');
+
+    const req = {
+      url: `http://www.example.com?host=${base64Host}`,
+    } as http.IncomingMessage;
+
+    expect(getEmbeddedAppUrl(req)).toBe(
+      'https://my-store.shopify.com/admin/apps/my-api-key',
+    );
+  });
+});

src/utils/get-host-app-url.ts → src/utils/get-embedded-app-url.ts

@@ -9,10 +9,12 @@ import {Context} from '../context';
  *
  * @param request Current HTTP request
  */
-export default function getHostAppUrl(request: http.IncomingMessage): string {
+export default function getEmbeddedAppUrl(
+  request: http.IncomingMessage,
+): string {
   if (!request) {
     throw new ShopifyErrors.MissingRequiredArgument(
-      'getHostAppUrl requires a request object argument',
+      'getEmbeddedAppUrl requires a request object argument',
     );
   }
 

src/utils/index.ts

@@ -11,7 +11,7 @@ import validateHmac from './hmac-validator';
 import validateShop from './shop-validator';
 import versionCompatible from './version-compatible';
 import withSession from './with-session';
-import getHostAppUrl from './get-host-app-url';
+import getEmbeddedAppUrl from './get-embedded-app-url';
 
 const ShopifyUtils = {
   decodeSessionToken,
@@ -27,7 +27,7 @@ const ShopifyUtils = {
   validateShop,
   versionCompatible,
   withSession,
-  getHostAppUrl,
+  getEmbeddedAppUrl,
 };
 
 export default ShopifyUtils;