Adding internet check to bitbar version plugin (matryer#387)

* Adding internet check to bitbar version plugin
- prevents showing and error when re-connecting to wifi

* Fixed checkstyle error in bitbar version plugin

* Simplified retry logic on connection error in bitbar version plugin

* Removed obsolete require

Author: oliviernt

BitBar/version.12h.rb

@@ -1,7 +1,7 @@
 #!/usr/bin/env ruby
 #
 # <bitbar.title>BitBar Version</bitbar.title>
-# <bitbar.version>v0.1.0</bitbar.version>
+# <bitbar.version>v0.2.0</bitbar.version>
 # <bitbar.author>Olivier Tille</bitbar.author>
 # <bitbar.author.github>oliviernt</bitbar.author.github>
 # <bitbar.image>http://i.imgur.com/9BrFhSJ.png</bitbar.image>
@@ -26,8 +26,22 @@
 # ?client_id=#{GITHUB_CLIENT_ID}&client_secret=#{GITHUB_CLIENT_SECRET}
 
 def get_json
-  url = "https://api.github.com/repos/matryer/bitbar/releases/latest"
-  json_result = JSON.parse(Net::HTTP.get(URI(url)))
+  url = URI("https://api.github.com/repos/matryer/bitbar/releases/latest")
+  json_result = nil
+  sleep_time = 0.5
+  sleep_until = 16 # sleep 5x (0,5 * 2 ^ 5 == 16)
+  while json_result.nil?
+    begin
+      json_result = JSON.parse(Net::HTTP.get(url))
+    rescue => e
+      sleep_time *= 2
+      if sleep_time < sleep_until
+        sleep sleep_time
+      else
+        throw e
+      end
+    end
+  end
   json_result
 end
 
@@ -48,8 +62,8 @@ def get_current_version(xml)
 end
 
 begin
-  current_version = get_current_version(get_xml)
   json_val = get_json
+  current_version = get_current_version(get_xml)
   latest_version = json_val["tag_name"]
   outdated = Gem::Version.new(current_version) < Gem::Version.new(latest_version.sub!("v", ""))
   color = outdated ? "red" : "green"
@@ -63,5 +77,5 @@ def get_current_version(xml)
 rescue => _
   puts "BitBar Version Error | color=red"
   puts "---"
-  puts "Content is currently unavailable. Please try resetting. | color=red"
+  puts "Content is currently unavailable. Please try resetting or check your internet connection. | color=red"
 end