version 0.1.0

.gitignore

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+doc
+pkg
+*.gem
+.idea
+

MIT-LICENSE

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+Copyright (c) 2009 Henning Koch
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.rdoc

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+= query_diet
+
+query_diet counts the number of database queries for the last request and *subtly* displays it in the upper right corner of your screen.
+The display turns red if too many queries are run, or if they take too long.
+This is useful to prevent {N + 1 queries}[http://guides.rubyonrails.org/active_record_querying.html#eager-loading-associations] from creeping into your code.
+
+== Installation
+
+Install the gem with
+    sudo gem install query_diet
+
+There is no further setup necessary after you add the <tt>query_diet</tt> dependency to your Rails application.
+
+We recommend you only use the gem with the development environment.
+
+== Changing warning thresholds
+
+You can define when the counter turns into a red warning. The default threshold is 8 queries and 5000 miliseconds.
+To change the default, add the following to <tt>config/initializers/query_diet.rb</tt>:
+
+    if defined?(QueryDiet)
+      QueryDiet::Logger.bad_count = 8
+      QueryDiet::Logger.bad_time = 5000
+    end
+
+== Rails 3 compatibility
+
+We cannot guarantee Rails 3 compatibility at this point, but we will upgrade the gem when Rails 3 is released.
+
+=== Credits
+
+Henning Koch
+
+{www.makandra.de}[http://www.makandra.de/]

Rakefile

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+require 'rake'
+# require 'rake/testtask'
+require 'rake/rdoctask'
+require 'spec/rake/spectask'
+
+desc 'Default: Run all specs.'
+task :default => :spec
+
+desc "Run all specs"
+Spec::Rake::SpecTask.new() do |t|
+  t.spec_opts = ['--options', "\"spec/support/spec.opts\""]
+  t.spec_files = FileList['spec/**/*_spec.rb']
+end
+
+desc 'Generate documentation for the query_diet gem.'
+Rake::RDocTask.new(:rdoc) do |rdoc|
+  rdoc.rdoc_dir = 'rdoc'
+  rdoc.title    = 'query_diet'
+  rdoc.options << '--line-numbers' << '--inline-source'
+  rdoc.rdoc_files.include('README')
+  rdoc.rdoc_files.include('lib/**/*.rb')
+end
+
+begin
+  require 'jeweler'
+  Jeweler::Tasks.new do |gemspec|
+    gemspec.name = "query_diet"
+    gemspec.summary = "Rails database query counter that stays out of your way"
+    gemspec.email = "github@makandra.de"
+    gemspec.homepage = "http://github.com/makandra/query_diet"
+    gemspec.description = "Rails database query counter that stays out of your way"
+    gemspec.authors = ["Henning Koch"]
+  end
+rescue LoadError
+  puts "Jeweler not available. Install it with: sudo gem install jeweler"
+end
+

VERSION

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+0.1.0

lib/query_diet.rb

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+require 'query_diet/logger'
+require 'query_diet/widget'
+require 'query_diet/active_record_ext'
+require 'query_diet/action_controller_ext'
+

lib/query_diet/action_controller_ext.rb

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+require_dependency 'application_controller'
+
+ApplicationController.class_eval do
+
+  around_filter :query_diet_logging
+
+  private
+
+  def query_diet_logging
+    QueryDiet::Logger.reset
+    yield
+    QueryDiet::Widget.render(response)
+  end
+
+end

lib/query_diet/active_record_ext.rb

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+ActiveRecord::Base.connection.class.class_eval do
+
+  def execute_with_query_diet(query, name = nil)
+    QueryDiet::Logger.log(query) do
+      execute_without_query_diet(query, name)
+    end
+  end
+
+  alias_method_chain :execute, :query_diet
+
+end

lib/query_diet/logger.rb

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+module QueryDiet
+  class Logger
+    class << self
+
+      attr_accessor :count, :time, :bad_count, :bad_time
+
+      def reset
+        self.count = 0
+        self.time = 0
+      end
+
+      def log(query, &execution)
+        result = nil
+        seconds = Benchmark.realtime do
+          result = execution.call
+        end
+        if log_query?(query)
+          self.time += (seconds * 1000).to_i
+          self.count += 1
+        end
+        result
+      end
+
+      def bad?
+        count >= bad_count or time >= bad_time
+      end
+
+      private
+
+      def log_query?(query)
+        query =~ /^(select|create|update|delete|insert)\b/i
+      end
+
+    end
+
+    reset
+    self.bad_count = 8
+    self.bad_time = 5000
+
+  end
+end

lib/query_diet/widget.rb

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+module QueryDiet
+  class Widget
+    class << self
+
+      def render(response)
+        body = response.body
+        if response.content_type == "text/html" && position = body.index('</body>')
+          body.insert(position, css)
+          body.insert(position, html)
+        end
+      end
+
+      private
+
+      def css
+        <<-EOF
+        <style type="text/css"><!--
+          div#query_diet {
+            position: absolute;
+            top: 0px;
+            right: 0px;
+            background-color: black;
+            color: white;
+            z-index: 999;
+            padding: 4px 6px;
+            font-family; arial, sans-serif;
+            font-size: 12px;
+            line-height: 12px;
+            font-weight: bold;
+            cursor: pointer;
+          }
+          div#query_diet.good {
+            xbackground-color: #160;
+            filter:alpha(opacity=30);
+            -moz-opacity:0.3;
+            -khtml-opacity: 0.3;
+            opacity: 0.3;
+          }
+          div#query_diet.bad {
+            background-color: red;
+            font-size: 16px;
+            line-height: 16px;
+          }
+        --></style>
+        EOF
+      end
+
+      def html
+        <<-EOF
+        <div id="query_diet" class="#{QueryDiet::Logger.bad? ? 'bad' : 'good' }" onclick="this.parentNode.removeChild(this);">
+          #{QueryDiet::Logger.count} / #{QueryDiet::Logger.time}ms
+        </div>
+        EOF
+      end
+
+    end
+  end
+end