From 430e8f18530e3328b116f88c04643308c8156cea Mon Sep 17 00:00:00 2001
From: David Bailey <4248177+davidbailey00@users.noreply.github.com>
Date: Tue, 6 Nov 2018 06:54:05 +0900
Subject: [PATCH] fix(gatsby-plugin-offline): Serve the offline shell for short
 URLs + use no-cors for external resources (#9679)

- Fixes the fallback whitelist regex so that short pages match (e.g. `/`), so that these are served offline correctly
- Uses `no-cors` mode when caching external resources, so that errors don't appear if the target doesn't allow CORS requests
- Allow insecure external resources to be cached for testing on `localhost`

Fixes #8145
---
 .../gatsby-plugin-offline/src/gatsby-node.js  |  4 ++--
 .../gatsby-plugin-offline/src/sw-append.js    | 20 ++++++++++++-------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/packages/gatsby-plugin-offline/src/gatsby-node.js b/packages/gatsby-plugin-offline/src/gatsby-node.js
index 874d1da1da3b7..a9f4419e93d21 100644
--- a/packages/gatsby-plugin-offline/src/gatsby-node.js
+++ b/packages/gatsby-plugin-offline/src/gatsby-node.js
@@ -88,7 +88,7 @@ exports.onPostBuild = (args, pluginOptions) => {
     // URLs and not any files hosted on the site.
     //
     // Regex based on http://stackoverflow.com/a/18017805
-    navigateFallbackWhitelist: [/^[^?]*([^.?]{5}|\.html)(\?.*)?$/],
+    navigateFallbackWhitelist: [/^([^.?]*|[^?]*\.([^.?]{5,}|html))(\?.*)?$/],
     navigateFallbackBlacklist: [/\?(.+&)?no-cache=1$/],
     cacheId: `gatsby-plugin-offline`,
     // Don't cache-bust JS or CSS files, and anything in the static directory
@@ -101,7 +101,7 @@ exports.onPostBuild = (args, pluginOptions) => {
       },
       {
         // Use the Network First handler for external resources
-        urlPattern: /^https:/,
+        urlPattern: /^https?:/,
         handler: `networkFirst`,
       },
     ],
diff --git a/packages/gatsby-plugin-offline/src/sw-append.js b/packages/gatsby-plugin-offline/src/sw-append.js
index e67dd18cb837b..a578d3708a9e9 100644
--- a/packages/gatsby-plugin-offline/src/sw-append.js
+++ b/packages/gatsby-plugin-offline/src/sw-append.js
@@ -9,13 +9,19 @@ self.addEventListener(`message`, event => {
     event.waitUntil(
       caches.open(cacheName).then(cache =>
         Promise.all(
-          resources.map(resource =>
-            cache.add(resource).catch(e => {
-              // ignore TypeErrors - these are usually due to
-              // external resources which don't allow CORS
-              if (!(e instanceof TypeError)) throw e
-            })
-          )
+          resources.map(resource => {
+            let request
+
+            // Some external resources don't allow
+            // CORS so get an opaque response
+            if (resource.match(/^https?:/)) {
+              request = fetch(resource, { mode: `no-cors` })
+            } else {
+              request = fetch(resource)
+            }
+
+            return request.then(response => cache.put(resource, response))
+          })
         )
       )
     )