fix: 404 response is cached when static files not found (#308)

* fix: vercel cached 404 requests

* fix: add static request fallback serverless

api/static-fallback/index.js

@@ -0,0 +1,17 @@
+/**
+ * @file static files not found fallback
+ * According to the config in vercel.json, we cached the
+ * static files with `max-age=X` header, but we may get 404
+ * response durning deploying, the default behavior for vercel
+ * would add the cache header to this 404 response, which caused
+ * the user can not get right resources anymore. so we should
+ * fallback to here and clear the cache header for such 404 requests.
+ * See also: https://github.com/conwnet/github1s/issues/299
+ * @author netcon
+ */
+
+module.exports = async (req, res) => {
+	res.status(404);
+	res.setHeader('Cache-Control', 'no-store');
+	res.send('Not Found');
+};

vercel.json

@@ -1,31 +1,49 @@
 {
-  "routes": [
+  "rewrites": [
     {
-      "src": "/api/sourcegraph",
-      "dest": "https://sourcegraph.com/.api/graphql"
+      "source": "/api/sourcegraph",
+      "destination": "https://sourcegraph.com/.api/graphql"
     },
     {
-      "src": "/static/(.*)",
-      "dest": "/static/$1",
-      "headers": {
-        "Cache-Control": "max-age=604800"
-      }
+      "source": "/api/github-auth-callback",
+      "destination": "/api/github-auth-callback"
     },
     {
-      "src": "/favicon(-dark|-light)?.ico",
-      "dest": "/favicon$1.ico"
+      "source": "/static/(.*)",
+      "destination": "/api/static-fallback"
     },
     {
-      "src": "/manifest.json",
-      "dest": "/manifest.json"
+      "source": "/(.*)",
+      "destination": "/index.html"
+    }
+  ],
+  "headers": [
+    {
+      "source": "/static/(.*)",
+      "headers": [
+        {
+          "key": "Cache-Control",
+          "value": "public, max-age=2592000, immutable"
+        }
+      ]
     },
     {
-      "src": "/api/github-auth-callback",
-      "dest": "/api/github-auth-callback"
+      "source": "/favicon(-dark|-light)?.ico",
+      "headers": [
+        {
+          "key": "Cache-Control",
+          "value": "public, max-age=3600"
+        }
+      ]
     },
     {
-      "src": ".*",
-      "dest": "/index.html"
+      "source": "/manifest.json",
+      "headers": [
+        {
+          "key": "Cache-Control",
+          "value": "public, max-age=3600"
+        }
+      ]
     }
   ]
-}
+}