working prototype

Author: codergeek121

.gitignore

@@ -8,3 +8,4 @@
 /test/dummy/log/*.log
 /test/dummy/storage/
 /test/dummy/tmp/
+Gemfile.lock

Gemfile

@@ -9,4 +9,4 @@ gem "puma"
 gem "sqlite3"
 
 # Start debugger with binding.b [https://github.com/ruby/debug]
-# gem "debug", ">= 1.0.0"
+gem "debug", ">= 1.0.0"

app/views/email_error_reporter/error_mailer/_frame.html.erb

@@ -0,0 +1 @@
+<li><%= frame %></li>

app/views/email_error_reporter/error_mailer/_no_backtrace.html.erb

@@ -0,0 +1 @@
+<p>No backtrace available</p>

app/views/email_error_reporter/error_mailer/error.html.erb

@@ -0,0 +1,6 @@
+<h1><%= @error.class %></h1>
+<p><%= @error.message %></p>
+
+<div>
+<%= render(partial: "frame", collection: @backtrace) || render("no_backtrace") -%>
+</div>

lib/email_error_reporter.rb

@@ -1,6 +1,10 @@
 require "email_error_reporter/version"
-require "email_error_reporter/railtie"
+require "email_error_reporter/engine"
 
 module EmailErrorReporter
-  # Your code goes here...
+  extend ActiveSupport::Autoload
+
+  autoload :ErrorMailer
+  autoload :Subscriber
+  autoload :ExceptionSerializer
 end

lib/email_error_reporter/engine.rb

@@ -0,0 +1,17 @@
+module EmailErrorReporter
+  class Engine < ::Rails::Engine
+    isolate_namespace EmailErrorReporter
+
+    config.email_error_reporter = ActiveSupport::OrderedOptions.new
+    config.email_error_reporter.to = []
+
+    initializer "email_error_reporter.error_subscribe" do
+      Rails.error.subscribe(Subscriber.new)
+    end
+
+    # ActiveJob cannot (de)-serialize exceptions by default
+    initializer "email_error_reporter.exception_serializer" do |app|
+      app.config.active_job.custom_serializers << ExceptionSerializer
+    end
+  end
+end

lib/email_error_reporter/error_mailer.rb

@@ -0,0 +1,18 @@
+module EmailErrorReporter
+  class ErrorMailer < ActionMailer::Base
+    def error(error, handled:, severity:, context:, source: nil)
+      @error = error
+      @handled = handled
+      @severity = severity
+      @context = context
+      @source = source
+
+      @backtrace = Array.wrap(error.backtrace)
+
+      mail(
+        subject: "#{error.class}",
+        to: Rails.application.config.email_error_reporter.to
+      )
+    end
+  end
+end

lib/email_error_reporter/exception_serializer.rb

@@ -0,0 +1,23 @@
+module EmailErrorReporter
+  class ExceptionSerializer < ActiveJob::Serializers::ObjectSerializer
+    def serialize(exception)
+      super(
+        exception_class: exception.class.to_s,
+        message: exception.message,
+        backtrace: exception.backtrace
+      )
+    end
+
+    def deserialize(hash)
+      hash[:exception_class].constantize.new(hash[:message]).tap do |e|
+        e.set_backtrace(hash[:backtrace])
+      end
+    end
+
+    private
+
+    def klass
+      Exception
+    end
+  end
+end

lib/email_error_reporter/railtie.rb

@@ -0,0 +1,7 @@
+module EmailErrorReporter
+  class Subscriber
+    def report(error, handled:, severity:, context:, source: nil)
+      ErrorMailer.error(error, handled: handled, context: context, source: source).deliver_later
+    end
+  end
+end

lib/email_error_reporter/subscriber.rb

@@ -0,0 +1,6 @@
+<h1>Exception</h1>
+<p>some message</p>
+
+<div>
+<p>No backtrace available</p>
+</div>

test/dummy/test/fixtures/email_error_reporter/error_mailer/error

@@ -0,0 +1,7 @@
+<h1>Exception</h1>
+<p>some message</p>
+
+<div>
+<li>foo</li>
+<li>bar</li>
+</div>

test/dummy/test/fixtures/email_error_reporter/error_mailer/error_with_backtrace

@@ -0,0 +1,30 @@
+require "test_helper"
+
+class EmailErrorReporter::ErrorMailerTest < ActionMailer::TestCase
+  test "renders the template correctly" do
+    exception = Exception.new("some message")
+    email = EmailErrorReporter::ErrorMailer.error(
+      exception,
+      handled: true,
+      severity: :info,
+      context: {}
+    )
+    assert_equal [], email.to
+    assert_equal "Exception", email.subject
+    assert_equal read_fixture("error").join, email.body.to_s
+  end
+
+  test "renders a backtrace" do
+    exception = Exception.new("some message")
+    exception.set_backtrace(["foo", "bar"])
+    email = EmailErrorReporter::ErrorMailer.error(
+      exception,
+      handled: true,
+      severity: :info,
+      context: {}
+    )
+    assert_equal [], email.to
+    assert_equal "Exception", email.subject
+    assert_equal read_fixture("error_with_backtrace").join, email.body.to_s
+  end
+end

test/error_mailer_test.rb

@@ -0,0 +1,23 @@
+require "test_helper"
+
+class SubscriberTest < ActiveSupport::TestCase
+  include ActionMailer::TestHelper
+
+  TestError = Class.new(StandardError)
+
+  test "enqueues a mail with the reported error" do
+    Rails.error.record(TestError) do
+      raise TestError
+    end
+
+  rescue TestError => e
+    assert_enqueued_email_with EmailErrorReporter::ErrorMailer, :error, args: ->(args) {
+      # TODO: find out, why args.first == e is false
+      [
+        args.first.message == e.message,
+        args.first.backtrace == e.backtrace,
+        args.first.class == e.class
+      ].all?
+    }
+  end
+end

test/subscriber_test.rb

@@ -5,6 +5,9 @@
 ActiveRecord::Migrator.migrations_paths = [File.expand_path("../test/dummy/db/migrate", __dir__)]
 require "rails/test_help"
 
+# require debugger for tests
+require "debug"
+
 # Load fixtures from the engine
 if ActiveSupport::TestCase.respond_to?(:fixture_paths=)
   ActiveSupport::TestCase.fixture_paths = [File.expand_path("fixtures", __dir__)]