Merge ea16f5d into c8bc953

README.md

@@ -89,6 +89,28 @@ const app = new App({
 })
 ```
 
+> **NOTE**: an optional `expiry` parameter is passed to `cache.set`, useful for further automation of your cache mechanism
+> _e.g. auto purge values after expiry is elapsed._
+
+```js
+const app = new App({
+  id: APP_ID,
+  privateKey: PRIVATE_KEY,
+  cache: {
+    get (key) {
+      return CACHE[key]
+    },
+    set (key, value, expiry) {
+      CACHE[key] = value
+
+      const timeout = (new Date(expiry)).getTime() - (new Date()).getTime();
+
+      setTimeout(() => delete CACHE[key], timeout)
+    }
+  }
+})
+```
+
 ## Using with GitHub Enterprise
 
 The `baseUrl` option can be used to override default GitHub's `https://api.github.com`:

lib/get-cache.js

@@ -4,10 +4,12 @@ module.exports = getCache
 const LRU = require('lru-cache')
 
 function getCache () {
-  return new LRU({
+  const lru = new LRU({
     // cache max. 15000 tokens, that will use less than 10mb memory
     max: 15000,
     // Cache for 1 minute less than GitHub expiry
     maxAge: 1000 * 60 * 59
   })
+
+  return { get: (key) => lru.get(key), set: (key, token) => lru.set(key, token) }
 }

lib/get-installation-access-token.js

@@ -19,7 +19,7 @@ function getInstallationAccessToken (state, { installationId }) {
       authorization: `bearer ${getSignedJsonWebToken(state)}`
     }
   }).then(response => {
-    state.cache.set(installationId, response.data.token)
+    state.cache.set(installationId, response.data.token, response.data.expires_at)
     return response.data.token
   })
 }