support ann as announce url

Author: TheBeastLT

lib/client/http-tracker.js

@@ -11,7 +11,7 @@ import Tracker from './tracker.js'
 import compact2string from 'compact2string'
 
 const debug = Debug('bittorrent-tracker:http-tracker')
-const HTTP_SCRAPE_SUPPORT = /\/(announce)[^/]*$/
+const HTTP_SCRAPE_SUPPORT = /(\/ann(?:ounce)?)[^/]*$/
 
 /**
  * HTTP torrent tracker client (for an individual tracker)
@@ -32,7 +32,7 @@ class HTTPTracker extends Tracker {
     const match = this.announceUrl.match(HTTP_SCRAPE_SUPPORT)
     if (match) {
       const pre = this.announceUrl.slice(0, match.index)
-      const post = this.announceUrl.slice(match.index + 9)
+      const post = this.announceUrl.slice(match.index + match[1].length)
       this.scrapeUrl = `${pre}/scrape${post}`
     }