Add the ability to specify the host

src/auth/create-top-level-redirect.ts

@@ -3,10 +3,12 @@ import querystring from 'querystring';
 import {Context} from 'koa';
 
 import redirectionPage from './redirection-page';
+import getHost from 'src/lib/get-host';
 
 export default function createTopLevelRedirect(apiKey: string, path: string) {
   return function topLevelRedirect(ctx: Context) {
-    const {host, query} = ctx;
+    const host = getHost(ctx);
+    const {query} = ctx;
     const {shop} = query;
 
     const params = {shop};

src/auth/oauth-query-string.ts

@@ -6,6 +6,7 @@ import nonce from 'nonce';
 import {OAuthStartOptions} from '../types';
 
 import getCookieOptions from './cookie-options';
+import getHost from 'src/lib/get-host';
 
 const createNonce = nonce();
 
@@ -14,7 +15,8 @@ export default function oAuthQueryString(
   options: OAuthStartOptions,
   callbackPath: string,
 ) {
-  const {host, cookies} = ctx;
+  const host = getHost(ctx);
+  const {cookies} = ctx;
   const {scopes = [], apiKey, accessMode} = options;
 
   const requestNonce = createNonce();

src/lib/get-host.ts

+import { Context } from 'koa';
+
+export default function getHost(ctx: Context) {
+    console.log({koaShopifyAuthEnv: process.env});
+    const {
+        SHOPIFY_APP_HOST
+    } = process.env;
+    return SHOPIFY_APP_HOST || ctx.host;
+}
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