Merge pull request #264 from jeremyjung/master

Add Email Statistics helper example

USE_CASES.md

@@ -237,3 +237,51 @@ Find more information about all of SendGrid's whitelabeling related documentatio
 You can find documentation for how to view your email statistics via the UI [here](https://app.sendgrid.com/statistics) and via API [here](https://github.com/sendgrid/sendgrid-ruby/blob/master/USAGE.md#stats).
 
 Alternatively, we can post events to a URL of your choice via our [Event Webhook](https://sendgrid.com/docs/API_Reference/Webhooks/event.html) about events that occur as SendGrid processes your email.
+
+You can also use the email statistics helper to make it easier to interact with the API.
+
+```ruby
+require 'sendgrid-ruby'
+require 'date'
+
+include SendGrid
+
+sg_client = SendGrid::API.new(api_key: ENV['SENDGRID_API_KEY']).client
+stats = SendGrid::EmailStats.new(sendgrid_client: sg_client)
+
+# Fetch stats by day, between 2 dates
+from = Date.new(2017, 10, 01)
+to = Date.new(2017, 10, 12)
+
+email_stats = stats.by_day(from, to)
+
+email_stats.metrics
+
+if !email_stats.error?
+  email_stats.metrics.each do |metric|
+    puts "Date - #{metric.date}"
+    puts "Number of Requests - #{metric.requests}"
+    puts "Bounces - #{metric.bounces}"
+    puts "Opens - #{metric.opens}"
+    puts "Clicks - #{metric.clicks}"
+  end
+end
+
+# Fetch stats by week, between 2 dates for a category
+from = Date.new(2017, 10, 01)
+to = Date.new(2017, 10, 12)
+category = 'abcd'
+
+email_stats = stats.by_week(from, to, category)
+
+if !email_stats.error?
+  email_stats.metrics.each do |metric|
+    puts "Date - #{metric.date}"
+    puts "Number of Requests - #{metric.requests}"
+    puts "Bounces - #{metric.bounces}"
+    puts "Opens - #{metric.opens}"
+    puts "Clicks - #{metric.clicks}"
+  end
+end
+
+```