add a max duration to key, change a method from get to post

download.html

@@ -34,17 +34,17 @@ var downloadlink = document.getElementById('downloadlink')
 var key = null
 var pollTimer = null
 
-function xhr(url, cb) {
+function xhr(method, url, cb) {
 	var x = new XMLHttpRequest()
 	x.onload = function () {
 		cb(x)
 	}
-	x.open('GET', url, true)
+	x.open(method, url, true)
 	x.send(null)
 }
 
 function pollFile () {
-	xhr('/status/' + key, function (x) {
+	xhr('GET', '/status/' + key, function (x) {
 		var data
 		try {
 			data = JSON.parse(x.responseText)
@@ -67,7 +67,7 @@ function generateKey () {
 	keyOutput.textContent = '- - - -'
 	if (pollTimer) clearInterval(pollTimer)
 	downloads.style.display = 'none'
-	xhr('/generate', function (x) {
+	xhr('POST', '/generate', function (x) {
 		keyOutput.textContent = x.responseText
 		if (x.responseText !== 'error') {
 			key = x.responseText

index.js

@@ -10,8 +10,9 @@ const fs = require('fs')
 const { spawn } = require('child_process')
 
 const port = 3001
-const expireDelay = 20
-const maxFileSize = 1024 * 1024 * 400
+const expireDelay = 30  // 30 seconds
+const maxExpireDuration = 2 * 60 * 60  // 2 hours
+const maxFileSize = 1024 * 1024 * 400  // 400 MB
 
 const keyChars = "123456789ACEFGHKLMNPRSTUVXYZ"
 const keyLength = 4
@@ -37,7 +38,7 @@ function removeKey (key) {
     }
     app.context.keys.delete(key)
   } else {
-    console.log('key dont exist', key)
+    console.log('Tried to remove non-existing key', key)
   }
 }
 
@@ -90,7 +91,7 @@ const upload = multer({
   }
 })
 
-router.get('/generate', async ctx => {
+router.post('/generate', async ctx => {
   const agent = ctx.get('user-agent')
   if (!agent.includes('Kobo')) {
     console.error('Non-Kobo device tried to generate a key: ' + agent)
@@ -98,25 +99,28 @@ router.get('/generate', async ctx => {
   }
   let key = null
   let attempts = 0
+  console.log('There are currently', ctx.keys.size, 'key(s) in use.')
+  console.log('Generating unique key...', agent)
   do {
     key = randomKey()
-    console.log(attempts, ctx.keys.size, key)
     if (attempts > ctx.keys.size) {
-      console.error('Can\'t generate more keys, map is full.')
+      console.error('Can\'t generate more keys, map is full.', attempts, ctx.keys.size)
       ctx.body = 'error'
       return
     }
     attempts++
   } while (ctx.keys.has(key))
 
+  console.log('Generated key ' + key + ', '+attempts+' attempt(s)')
+
   const info = {
     created: new Date(),
     agent: agent,
     file: null
   }
-  console.log(info)
   ctx.keys.set(key, info)
   expireKey(key)
+  setTimeout(removeKey, maxExpireDuration * 1000, key)
 
   ctx.body = key
 })