translator: connect to sites only when necessary

Previously the translation services in the plugin would connect to their
respective websites on initialize. Now they will only do this when the first
time they are used. WorldLingo still connects on initialialize in order to list
the supported language pairs, but the Mechanize object is not saved here, so
the connection should be closed after initialize, and only reopened if
translation by WorldLingo is requested later.

Previously the services are assumed to fail if they raise any Exception in
initialize, and in that case the service is disabled, and its command as well
as the help translate [failed] commands state this. Now this exception catch is
done for any do_translate method call.

1 files changed, 45 insertions, 35 deletions

diff --git a/data/rbot/plugins/translator.rb b/data/rbot/plugins/translator.rb
index 6b87476c..9fb74e8a 100644
--- a/data/rbot/plugins/translator.rb
+++ b/data/rbot/plugins/translator.rb
@@ -110,12 +110,12 @@ class NiftyTranslator < Translator
   def initialize(cache={})
    require 'mechanize'
    super(Translator::Direction.all_from_to(%w[ja en zh_CN ko], %w[ja]), cache)
-    @form = WWW::Mechanize.new.
-            get('http://nifty.amikai.com/amitext/indexUTF8.jsp').
-            forms_with(:name => 'translateForm').last
   end
 
   def do_translate(text, from, to)
+    @form ||= WWW::Mechanize.new.
+              get('http://nifty.amikai.com/amitext/indexUTF8.jsp').
+              forms_with(:name => 'translateForm').last
     @radio = @form.radiobuttons_with(:name => 'langpair').first
     @radio.value = "#{from},#{to}".upcase
     @radio.check
@@ -215,16 +215,18 @@ class BabelfishTranslator < Translator
 
   def initialize(cache)
     require 'mechanize'
-
-    @form = WWW::Mechanize.new.get('http://babelfish.altavista.com/babelfish/').
-            forms_with(:name => 'frmTrText').first
-    @lang_list = @form.fields_with(:name => 'lp').first
-    language_pairs = @lang_list.options.map {|o| o.value.split('_')}.
-                                            reject {|p| p.empty?}
+    form = WWW::Mechanize.new.get('http://babelfish.altavista.com/babelfish/').
+           forms_with(:name => 'frmTrText').first
+    lang_list = form.fields_with(:name => 'lp').first
+    language_pairs = lang_list.options.map {|o| o.value.split('_')}.
+                                           reject {|p| p.empty?}
     super(Translator::Direction.pairs(language_pairs), cache)
   end
 
   def do_translate(text, from, to)
+    @form ||= WWW::Mechanize.new.get('http://babelfish.altavista.com/babelfish/').
+              forms_with(:name => 'frmTrText').first
+
     if @form.fields_with(:name => 'trtext').empty?
       @form.add_field!('trtext', text)
     else
@@ -278,17 +280,10 @@ class TranslatorPlugin < Plugin
     @failed_translators = []
     @translators = {}
     TRANSLATORS.each_pair do |name, c|
-      begin
+      watch_for_fail(name) do
         @translators[name] = c.new(@registry.sub_registry(name))
         map "#{name} :from :to *phrase",
           :action => :cmd_translate, :thread => true
-      rescue Exception
-        @failed_translators << { :name => name, :reason => $!.to_s }
-
-        warning _("Translator %{name} cannot be used: %{reason}") %
-               {:name => name, :reason => $!}
-        map "#{name} [*args]", :action => :failed_translator,
-                               :defaults => {:name => name, :reason => $!}
       end
     end
 
@@ -300,6 +295,19 @@ class TranslatorPlugin < Plugin
     update_default
   end
 
+  def watch_for_fail(name, &block)
+    begin
+      yield
+    rescue Exception
+      @failed_translators << { :name => name, :reason => $!.to_s }
+
+      warning _("Translator %{name} cannot be used: %{reason}") %
+             {:name => name, :reason => $!}
+      map "#{name} [*args]", :action => :failed_translator,
+                             :defaults => {:name => name, :reason => $!}
+    end
+  end
+
   def failed_translator(m, params)
     m.reply _("Translator %{name} cannot be used: %{reason}") %
             {:name => params[:name], :reason => params[:reason]}
@@ -385,25 +393,27 @@ class TranslatorPlugin < Plugin
     translator = @translators[tname]
     from, to, phrase = params[:from], params[:to], params[:phrase].to_s
     if translator
-      begin
-        translation = Timeout.timeout(@bot.config['translator.timeout']) do
-          translator.translate(phrase, from, to)
+      watch_for_fail(tname) do
+        begin
+          translation = Timeout.timeout(@bot.config['translator.timeout']) do
+            translator.translate(phrase, from, to)
+          end
+          m.reply(if params[:show_provider]
+                    _('%{translation} (provided by %{translator})') %
+                      {:translation => translation, :translator => tname.gsub("_", " ")}
+                  else
+                    translation
+                  end)
+
+        rescue Translator::UnsupportedDirectionError
+          m.reply _("%{translator} doesn't support translating from %{source} to %{target}") %
+                  {:translator => tname, :source => from, :target => to}
+        rescue Translator::NoTranslationError
+          m.reply _('%{translator} failed to provide a translation') %
+                  {:translator => tname}
+        rescue Timeout::Error
+          m.reply _('The translator timed out')
         end
-        m.reply(if params[:show_provider]
-                  _('%{translation} (provided by %{translator})') %
-                    {:translation => translation, :translator => tname.gsub("_", " ")}
-                else
-                  translation
-                end)
-
-      rescue Translator::UnsupportedDirectionError
-        m.reply _("%{translator} doesn't support translating from %{source} to %{target}") %
-                {:translator => tname, :source => from, :target => to}
-      rescue Translator::NoTranslationError
-        m.reply _('%{translator} failed to provide a translation') %
-                {:translator => tname}
-      rescue Timeout::Error
-        m.reply _('The translator timed out')
       end
     else
       m.reply _('No translator called %{name}') % {:name => tname}