Fix the list of banners we select from.

src/Miscellaneous/Banner.coffee

@@ -1,4 +1,6 @@
 Banner =
+  banners: `<%= JSON.stringify(grunt.file.readJSON('src/Miscellaneous/banners.json')) %>`
+
   init: ->
     $.asap (-> d.body), ->
       $.asap (-> $ 'hr'), Banner.ready
@@ -35,16 +37,9 @@ Banner =
       d.title = title
 
   cb:
-    toggle: do ->
-      types =
-        jpg: 227
-        png: 270
-        gif: 253
-
-      ->
-        type = Object.keys(types)[Math.floor 3 * Math.random()]
-        num = Math.floor types[type] * Math.random()
-        $('img', @parentNode).src = "//s.4cdn.org/image/title/#{num}.#{type}"
+    toggle: ->
+      banner = Banner.banners[Math.floor(Banner.banners.length * Math.random())]
+      $('img', @parentNode).src = "//s.4cdn.org/image/title/#{banner}"
       
     click: (e) ->
       if e.ctrlKey

tools/banners.py

@@ -0,0 +1,17 @@
+#!/usr/bin/env python3
+import urllib.request, urllib.error, json
+banners = []
+for ext in ['jpg', 'png', 'gif']:
+  for i in range(300):
+    banner = str(i) + '.' + ext
+    req = urllib.request.Request('http://s.4cdn.org/image/title/' + banner, method='HEAD')
+    try:
+      status = urllib.request.urlopen(req).status
+    except urllib.error.HTTPError as e:
+      status = e.status
+    print(banner, status)
+    if status == 200:
+      banners.append(banner)
+with open('src/Miscellaneous/banners.json', 'w') as f:
+  f.write(json.dumps(banners))
+