add stats page

Gemfile

@@ -39,6 +39,7 @@ gem "oauth" # for twitter-posting bot
 gem "mail" # for parsing incoming mail
 gem "ruumba" # tests views
 gem "sitemap_generator" # for better search engine indexing
+gem "svg-graph", require: 'SVG/Graph/TimeSeries' # for charting, note workaround in lib/time_series.rb
 gem 'transaction_retry' # mitigate https://github.com/lobsters/lobsters-ansible/issues/39
 
 group :test, :development do

Gemfile.lock

@@ -231,6 +231,7 @@ GEM
       actionpack (>= 3.0)
       activesupport (>= 3.0)
       sprockets (>= 2.8, < 4.0)
+    svg-graph (2.2.0)
     thor (1.0.1)
     thread_safe (0.3.6)
     transaction_isolation (1.0.5)
@@ -296,6 +297,7 @@ DEPENDENCIES
   scenic-mysql_adapter
   sitemap_generator
   sprockets-rails (= 2.3.3)
+  svg-graph
   transaction_retry
   uglifier (>= 1.3.0)
   vcr

app/controllers/stats_controller.rb

@@ -0,0 +1,77 @@
+class StatsController < ApplicationController
+  FIRST_MONTH = Time.new(2012, 7, 3).utc.freeze
+  TIMESCALE_DIVISIONS = "1 year".freeze
+
+  def index
+    @title = "Stats"
+
+    @users_graph = monthly_graph("users_graph", {
+      :graph_title => "Users joining by month",
+      :scale_y_divisions => 50,
+    }) {
+      User.group("date_format(created_at, '%Y-%m')")
+    }
+
+    @stories_graph = monthly_graph("stories_graph", {
+      :graph_title => "Stories submitted by month",
+      :scale_y_divisions => 100,
+    }) {
+      Story.group("date_format(created_at, '%Y-%m')")
+    }
+
+    @comments_graph = monthly_graph("comments_graph", {
+      :graph_title => "Comments posted by month",
+      :scale_y_divisions => 1_000,
+    }) {
+      Comment.group("date_format(created_at, '%Y-%m')")
+    }
+
+    @votes_graph = monthly_graph("votes_graph", {
+      :graph_title => "Votes cast by month",
+      :scale_y_divisions => 10_000,
+    }) {
+      Vote.group("date_format(updated_at, '%Y-%m')")
+    }
+  end
+
+private
+
+  def monthly_graph(cache_key, opts)
+    Rails.cache.fetch(cache_key, expires_in: 1.day) {
+      defaults = {
+        :width => 800,
+        :height => 300,
+        :graph_title => "Graph",
+        :show_graph_title => false,
+        :no_css => false,
+        :key => false,
+        :scale_x_integers => true,
+        :scale_y_integers => false,
+        :show_data_values => false,
+        :show_x_guidelines => false,
+        :show_x_title => false,
+        :x_title => "Time",
+        :show_y_title => false,
+        :y_title => "Users",
+        :y_title_text_direction => :bt,
+        :stagger_x_labels => false,
+        :x_label_format => "%Y-%m",
+        :y_label_format => "%Y-%m",
+        :min_x_value => FIRST_MONTH,
+        :timescale_divisions => TIMESCALE_DIVISIONS,
+        :add_popups => true,
+        :popup_format => "%Y-%m",
+        :area_fill => false,
+        :min_y_value => 0,
+        :number_format => "%d",
+        :show_lines => false,
+      }
+      graph = TimeSeries.new(defaults.merge(opts))
+      graph.add_data(
+        data: yield.count.to_a.flatten,
+        template: "%Y-%m",
+      )
+      graph.burn_svg_only
+    }
+  end
+end

app/views/home/about.html.erb

@@ -148,7 +148,8 @@
 
   <p id="queries">
   The Lobsters community is in a sweet spot that it's large enough to be worth asking questions about and small enough the answers make sense.
-  If you're curious about stats, Peter is happy to run queries against the <a href="https://github.com/lobsters/lobsters/blob/master/db/schema.rb">database</a> and Rails/MySQL/nginx logs (but not write them for you),
+  We have <a href="/stats">some basic stats</a> available,
+  and Peter is happy to run queries against the <a href="https://github.com/lobsters/lobsters/blob/master/db/schema.rb">database</a> and Rails/MySQL/nginx logs (but not write them for you),
   as long as they don't reveal personal info like IPs, browsing, and voting or create “worst-of” leaderboards celebrating most-downvoted users/comments/stories.
   If you're an academic researcher, please <a href="https://lobste.rs/s/cqnzl5/lobste_rs_access_pattern_statistics_for">be like MIT</a>, not like <a href="https://github.com/lobsters/lobsters/issues/517">UChicago</a> secretly experimenting on maintainers without IRB review.
   </p>

app/views/stats/index.html.erb

@@ -0,0 +1,28 @@
+<div class="box wide">
+
+<h2>New users by month</h2>
+<%= raw @users_graph %>
+
+<h2>Stories submitted by month</h2>
+<%= raw @stories_graph %>
+
+<h2>Comments posted by month</h2>
+<%= raw @comments_graph %>
+
+<h2>Votes cast by month</h2>
+<%= raw @votes_graph %>
+
+<p>
+Want more info?
+<a href="/about#queries">Write a query</a>.
+</p>
+
+<style type="text/css">
+.graphBackground { fill: #ffffff; }
+.axis { stroke: #cccccc; }
+.dataPoint1 { color: #ac130d; }
+.line1 { color: #ac130d; }
+.guideLines { stroke: #ffffff; stroke-dasharray: none; }
+</style>
+
+</div>

config/application.rb

@@ -58,6 +58,7 @@ module Lobsters
 
     config.after_initialize do
       require "#{Rails.root}/lib/monkey.rb"
+      require "#{Rails.root}/lib/time_series.rb"
     end
 
     config.generators do |g|

config/routes.rb

@@ -209,5 +209,7 @@ Rails.application.routes.draw do
   get "/about" => "home#about"
   get "/chat" => "home#chat"
 
+  get "/stats" => "stats#index"
+
   post '/csp-violation-report' => 'csp#violation_report'
 end

lib/time_series.rb

@@ -0,0 +1,21 @@
+class TimeSeries < SVG::Graph::TimeSeries
+  include ActionView::Helpers::NumberHelper
+
+  # these two methods are a patch on the gem's lack of time zone awareness
+  def format x, y, description
+    [
+      Time.at(x).utc.strftime(popup_format),
+      number_with_delimiter(y),
+      description,
+    ].compact.join(', ')
+  end
+
+  def get_x_labels
+    get_x_values.collect {|v| Time.at(v).utc.strftime(x_label_format) }
+  end
+
+  # improves y axis labels with commas
+  def get_y_labels
+    get_y_values.collect {|v| number_with_delimiter(v.to_i) }
+  end
+end