From 70574220772a3f04f3e8ca1ddb66079201b23a5e Mon Sep 17 00:00:00 2001
From: Alexey Sachkov <sachkov2011@gmail.com>
Date: Sat, 20 Feb 2021 01:58:02 +0300
Subject: [PATCH] Enable caching of static assets (#1217)

* Enable caching of static assets

* Remove dependency on mime package

Since we only care about two file extensions at the moment,
there is no need to grab the whole package just to avoid
calling 'endsWith' twice.
---
 package-lock.json          | 12 ++++++------
 server.js                  |  9 ++-------
 server/static-assets.mv.js | 31 +++++++++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 13 deletions(-)
 create mode 100644 server/static-assets.mv.js

diff --git a/package-lock.json b/package-lock.json
index 0a72720bf..7f60226b6 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -4321,6 +4321,12 @@
             "pify": "^4.0.1",
             "semver": "^5.6.0"
           }
+        },
+        "mime": {
+          "version": "1.6.0",
+          "resolved": "https://registry.npmjs.org/mime/-/mime-1.6.0.tgz",
+          "integrity": "sha512-x0Vn8spI+wuJ1O6S7gnbaQg8Pxh4NNHb7KSINmEWKiPE4RKOplvijn+NkmYmmRgP68mc70j2EbeTFRsrswaQeg==",
+          "optional": true
         }
       }
     },
@@ -4570,12 +4576,6 @@
         }
       }
     },
-    "mime": {
-      "version": "1.6.0",
-      "resolved": "https://registry.npmjs.org/mime/-/mime-1.6.0.tgz",
-      "integrity": "sha512-x0Vn8spI+wuJ1O6S7gnbaQg8Pxh4NNHb7KSINmEWKiPE4RKOplvijn+NkmYmmRgP68mc70j2EbeTFRsrswaQeg==",
-      "optional": true
-    },
     "mime-db": {
       "version": "1.44.0",
       "resolved": "https://registry.npmjs.org/mime-db/-/mime-db-1.44.0.tgz",
diff --git a/server.js b/server.js
index c149e113a..92a17c301 100644
--- a/server.js
+++ b/server.js
@@ -1,18 +1,13 @@
 const _ = require('lodash');
 const jwt = require('jwt-simple');
-const expressStaticGzip = require('express-static-gzip');
 const express = require('express');
 const app = express();
 
 const homebrewApi = require('./server/homebrew.api.js');
 const GoogleActions = require('./server/googleActions.js');
+const serveCompressedStaticAssets = require('./server/static-assets.mv.js');
 
-// Serve brotli-compressed static files if available
-app.use('/', expressStaticGzip(`${__dirname}/build`, {
-	enableBrotli    : true,
-	orderPreference : ['br'],
-	index           : false
-}));
+app.use('/', serveCompressedStaticAssets(`${__dirname}/build`));
 
 process.chdir(__dirname);
 
diff --git a/server/static-assets.mv.js b/server/static-assets.mv.js
new file mode 100644
index 000000000..732420d46
--- /dev/null
+++ b/server/static-assets.mv.js
@@ -0,0 +1,31 @@
+const expressStaticGzip = require('express-static-gzip');
+
+// Serve brotli-compressed static files if available
+const customCacheControlHandler=(response, path)=>{
+	if(path.endsWith('.br')) {
+		// Drop .br suffix to help mime understand the actual type of the file
+		path = path.slice(0, -3);
+	}
+	if(path.endsWith('.js') || path.endsWith('.css')) {
+		// .js and .css files are allowed to be cached up to 12 hours, but then
+		// they must be revalidated to see if there are any updates
+		response.setHeader('Cache-Control', 'public, max-age: 43200, must-revalidate');
+	} else {
+		// Everything else is cached up to a months as we don't update our images
+		// or fonts frequently
+		response.setHeader('Cache-Control', 'public, max-age=2592000, must-revalidate');
+	}
+};
+
+const init=(pathToAssets)=>{
+	return expressStaticGzip(pathToAssets, {
+		enableBrotli    : true,
+		orderPreference : ['br'],
+		index           : false,
+		serveStatic     : {
+			cacheControl : false, // we are going to use custom cache-control
+			setHeaders   : customCacheControlHandler
+		} });
+};
+
+module.exports = init;