Add :condition option to dynamically evaluate if an email should be intercepted

Author: bobbus

README.md

@@ -34,6 +34,14 @@ Optionally prefix the subject line:
       subject_prefix: '[STAGING]'
     )
 
+Optionally intercept emails :
+
+    Mail.register_interceptor RecipientInterceptor.new(
+      ENV['EMAIL_RECIPIENTS'],
+      condition: lambda { |message| message.subject =~ /Error/ } # if the condition proc return true the email is intercepted
+    )
+
+
 Credits
 -------
 

lib/recipient_interceptor.rb

@@ -4,9 +4,11 @@ class RecipientInterceptor
   def initialize(recipients, options = {})
     @recipients = normalize_to_array(recipients)
     @subject_prefix = options[:subject_prefix]
+    @condition = options[:condition]
   end
 
   def delivering_email(message)
+    return if @condition && !@condition.call(message)
     add_custom_headers message
     add_subject_prefix message
     message.to = @recipients

spec/recipient_interceptor_spec.rb

@@ -59,6 +59,42 @@
     expect(response.subject).to eq '[STAGING] some subject'
   end
 
+  describe 'with a :condition option' do
+
+    it 'does not intercept if condition proc evaluate to false' do
+      Mail.register_interceptor RecipientInterceptor.new(
+        recipient_string,
+        condition: lambda { |m| false }
+        )
+
+      response = deliver_mail
+
+      expect(response.to).to eq ['[email protected]']
+    end
+
+    it 'does intercept if condition proc evaluate to true' do
+      Mail.register_interceptor RecipientInterceptor.new(
+        recipient_string,
+        condition: lambda { |m| true }
+        )
+
+      response = deliver_mail
+
+      expect(response.to).to eq [recipient_string]
+    end
+
+    it 'pass the message object to the condition proc' do
+      Mail.register_interceptor RecipientInterceptor.new(
+        recipient_string,
+        condition: lambda { |m| m.to == ['[email protected]'] }
+        )
+
+      response = deliver_mail
+
+      expect(response.to).to eq [recipient_string]
+    end
+  end
+
   def recipient_string
     '[email protected]'
   end