Add lru cache for live badges

libs/live-fns/npm.js

@@ -1,6 +1,6 @@
 const r2 = require('r2')
 
-module.exports = async function (args) {
+module.exports = async function (...args) {
   const version = await fetchVersion(args.join('%2F'), args[0][0] === '@')
 
   return {
@@ -18,6 +18,7 @@ async function fetchVersion (pkg, scoped) {
     const fullMeta = (await r2(endpoint).json)
     return fullMeta.versions[fullMeta['dist-tags']['latest']].version
   } else {
+    // a smaller response for just latest version
     const endpointLatest = `https://registry.npmjs.org/${pkg}/latest`
     return (await r2(endpointLatest).json).version
   }

libs/setup-live-badge.js

@@ -1,14 +1,20 @@
+const LRU = require('lru-cache')
 const liveFns = require('./live-fns/index.js')
 
+const cache = LRU({
+  max: 5000,
+  maxAge: 3e4,
+  stale: true
+})
+
 module.exports = function (router) {
   Object.entries(liveFns).forEach(([key, fn]) => {
     router.get(`/${key}/*`, async (req, res, params) => {
-      // todo: cache
       const {
         subject = key,
         status = 'unknown',
         color = 'grey'
-      } = await timeout(fn(params['*'].split('/')), 30000).catch(e => ({}))
+      } = await fetchLiveParams(key, params['*'], fn)
 
       res.writeHead(302, {
         Location: `https://badgen.now.sh/badge/${subject}/${status}/${color}`
@@ -16,6 +22,42 @@ module.exports = function (router) {
       res.end()
     })
   })
+
+  router.get('/list-cache-live', (req, res) => {
+    res.writeHead(200)
+    res.end(`Total ${cache.length}\n${cache.keys().join('\n')}`)
+  })
+
+  router.get('/clear-cache-live', (req, res) => {
+    const count = cache.length
+    const keys = cache.keys().join('\n')
+    cache.reset()
+
+    res.writeHead(200)
+    res.end(`Cleaned ${count}\n${keys}`)
+  })
+}
+
+async function fetchLiveParams (key, paramsPath, fn) {
+  const cached = cache.get(paramsPath)
+  if (cached) {
+    return cached
+  } else {
+    const logStamp = `$${key} ${paramsPath}`
+    console.time(logStamp)
+    return timeout(fn(...paramsPath.split('/')), 30000)
+      .then(fetched => {
+        // Update cache if deleted (after got stale)
+        cache.has(paramsPath) || cache.set(paramsPath, fetched)
+        return fetched
+      }, e => {
+        console.error(e)
+        return {}
+      }).then(result => {
+        console.timeEnd(logStamp)
+        return result
+      })
+  }
 }
 
 function timeout (promise, period) {