Add file system cache

package.json

@@ -2,7 +2,7 @@
   "name": "bandwidth-hero-proxy",
   "main": "server.js",
   "private": true,
-  "version": "1.0.2",
+  "version": "1.0.3",
   "description": "Data compression service that converts images to low-res WebP or JPEG on the fly. Used in Bandwidth-Hero browser extension.",
   "author": "Anatoliy Yastreb",
   "license": "MIT",
@@ -11,6 +11,8 @@
   },
   "dependencies": {
     "basic-auth": "^2.0.0",
+    "cache-manager": "^2.6.0",
+    "cache-manager-fs-binary": "^1.0.4",
     "express": "4.16.2",
     "lodash": "^4.17.4",
     "request": "^2.83.0",

src/compress.js

@@ -1,27 +1,42 @@
 const sharp = require('sharp')
 const redirect = require('./redirect')
+const cacheMgr = require('cache-manager')
+const cacheStore = require('cache-manager-fs-binary')
+const cache = cacheMgr.caching({
+    store: cacheStore,
+    options: {
+        ttl: 604800, //7d
+        maxsize: 1073741824, //1GB
+        path: './cache',
+        preventfill: true
+    }
+})
 
 function compress(req, res, input) {
   const format = req.params.webp ? 'webp' : 'jpeg'
+  const key = req.params.url || ''
 
-  sharp(input)
+  cache.wrap(key, (callback) => {
+    sharp(input)
     .grayscale(req.params.grayscale)
     .toFormat(format, {
       quality: req.params.quality,
       progressive: true,
       optimizeScans: true
     })
     .toBuffer((err, output, info) => {
-      if (err || !info || res.headersSent) return redirect(req, res)
-
-      res.setHeader('content-type', `image/${format}`)
-      res.setHeader('content-length', info.size)
-      res.setHeader('x-original-size', req.params.originSize)
-      res.setHeader('x-bytes-saved', req.params.originSize - info.size)
-      res.status(200)
-      res.write(output)
-      res.end()
+      callback(err, {binary: {output: output}, info: info})
     })
+  }, (err, obj) => {
+    if (err || !obj || !obj.info || res.headersSent) return redirect(req, res)
+    res.setHeader('content-type', `image/${format}`)
+    res.setHeader('content-length', obj.info.size)
+    res.setHeader('x-original-size', req.params.originSize)
+    res.setHeader('x-bytes-saved', req.params.originSize - obj.info.size)
+    res.status(200)
+    res.write(obj.binary.output)
+    res.end()
+  })
 }
 
 module.exports = compress