= Exception Notifier Plugin for Rails

The Exception Notifier plugin provides a mailer object and a default set of
templates for sending email notifications when errors occur in a Rails
application. The plugin is configurable, allowing programmers to specify:

* the sender address of the email
* the recipient addresses
* the text used to prefix the subject line

The email includes information about the current request, session, and
environment, and also gives a backtrace of the exception.

== Usage

First, include the ExceptionNotifiable mixin in whichever controller you want
to generate error emails (typically ApplicationController):

  class ApplicationController < ActionController::Base
    include ExceptionNotification::Notifiable
    ...
  end

Then, specify the email recipients in your environment:

  ExceptionNotification::Notifier.exception_recipients = %w([email protected] [email protected])

And that's it! The defaults take care of the rest.

== Configuration

You can tweak other values to your liking, as well. In your environment file,
just set any or all of the following values:

  # defaults to [email protected]
  ExceptionNotification::Notifier.sender_address =
    %("Application Error" <[email protected]>)

  # defaults to "[ERROR] "
  ExceptionNotification::Notifier.email_prefix = "[APP] "

Even if you have mixed into ApplicationController you can skip notification in
some controllers by
  
  class MyController  < ApplicationController
    skip_exception_notifications
  end
  
== Deprecated local_request? overriding

Email notifications will only occur when the IP address is determined not to
be local. You can specify certain addresses to always be local so that you'll
get a detailed error instead of the generic error page. You do this in your
controller (or even per-controller):

  consider_local "64.72.18.143", "14.17.21.25"

You can specify subnet masks as well, so that all matching addresses are
considered local:

  consider_local "64.72.18.143/24"

The address "127.0.0.1" is always considered local. If you want to completely
reset the list of all addresses (for instance, if you wanted "127.0.0.1" to
NOT be considered local), you can simply do, somewhere in your controller:

  local_addresses.clear

NOTE: The above functionality has has been pulled out to consider_local.rb,
as interfering with rails local determination is orthogonal to notification, 
unnecessarily clutters backtraces, and even occasionally errs on odd ip or 
requests bugs. To return original functionality add an initializer with:
 
  ActionController::Base.send :include, ConsiderLocal

or just include it per controller that wants it

 class MyController  < ApplicationController
   include ExceptionNotification::ConsiderLocal
 end

== Customization

By default, the notification email includes four parts: request, session,
environment, and backtrace (in that order). You can customize how each of those
sections are rendered by placing a partial named for that part in your
app/views/exception_notifier directory (e.g., _session.rhtml). Each partial has
access to the following variables:

* @controller: the controller that caused the error
* @request: the current request object
* @exception: the exception that was raised
* @host: the name of the host that made the request
* @backtrace: a sanitized version of the exception's backtrace
* @rails_root: a sanitized version of RAILS_ROOT
* @data: a hash of optional data values that were passed to the notifier
* @sections: the array of sections to include in the email

You can reorder the sections, or exclude sections completely, by altering the
ExceptionNotification::Notifier.sections variable. You can even add new sections that
describe application-specific data--just add the section's name to the list
(whereever you'd like), and define the corresponding partial. Then, if your
new section requires information that isn't available by default, make sure
it is made available to the email using the exception_data macro:

  class ApplicationController < ActionController::Base
    ...
    protected
      exception_data :additional_data

      def additional_data
        { :document => @document,
          :person => @person }
      end
    ...
  end

In the above case, @document and @person would be made available to the email
renderer, allowing your new section(s) to access and display them. See the
existing sections defined by the plugin for examples of how to write your own.

== 404s errors

Notification is skipped if you return a 404 status, which happens by default 
for an ActiveRecord::RecordNotFound or ActionController::UnknownAction error.

== Manually notifying of error in a rescue block

If your controller action manually handles an error, the notifier will never be
run.  To manually notify of an error call notify_about_exception from within the
rescue block

  def index
    #risky operation here
  rescue StandardError => error
    #custom error handling here
    notify_about_exception(error)
  end

== Support and tickets

https://rails.lighthouseapp.com/projects/8995-rails-plugins

Copyright (c) 2005 Jamis Buck, released under the MIT license