require 'net/smtp'
require 'tmail'
require 'erb'
module Rack
# Catches all exceptions raised from the app it wraps and
# sends a useful email with the exception, stacktrace, and
# contents of the environment.
class MailExceptions
attr_reader :config
def initialize(app)
@app = app
@config = {
:to => nil,
:from => ENV['USER'] || 'rack',
:subject => '[exception] %s',
:smtp => {
:server => 'localhost',
:domain => 'localhost',
:port => 25,
:authentication => :login,
:user_name => nil,
:password => nil
}
}
@template = ERB.new(TEMPLATE)
yield self if block_given?
end
def call(env)
status, headers, body =
begin
@app.call(env)
rescue => boom
# TODO don't allow exceptions from send_notification to
# propogate
send_notification boom, env
raise
end
send_notification env['mail.exception'], env if env['mail.exception']
[status, headers, body]
end
%w[to from subject].each do |meth|
define_method(meth) { |value| @config[meth.to_sym] = value }
end
def smtp(settings={})
@config[:smtp].merge! settings
end
private
def generate_mail(exception, env)
mail = TMail::Mail.new
mail.to = Array(config[:to])
mail.from = config[:from]
mail.subject = config[:subject] % [exception.to_s]
mail.date = Time.now
mail.set_content_type 'text/plain'
mail.charset = 'UTF-8'
mail.body = @template.result(binding)
mail
end
def send_notification(exception, env)
mail = generate_mail(exception, env)
smtp = config[:smtp]
env['mail.sent'] = true
return if smtp[:server] == 'example.com'
Net::SMTP.start smtp[:server], smtp[:port], smtp[:domain], smtp[:user_name], smtp[:password], smtp[:authentication] do |server|
mail.to.each do |recipient|
server.send_message mail.to_s, mail.from, recipient
end
end
end
def extract_body(env)
if io = env['rack.input']
io.rewind if io.respond_to?(:rewind)
io.read
end
end
TEMPLATE = (<<-'EMAIL').gsub(/^ {4}/, '')
A <%= exception.class.to_s %> occured: <%= exception.to_s %>
<% if body = extract_body(env) %>
===================================================================
Request Body:
===================================================================
<%= body.gsub(/^/, ' ') %>
<% end %>
===================================================================
Rack Environment:
===================================================================
PID: <%= $$ %>
PWD: <%= Dir.getwd %>
<%= env.to_a.
sort{|a,b| a.first <=> b.first}.
map{ |k,v| "%-25s%p" % [k+':', v] }.
join("\n ") %>
<% if exception.respond_to?(:backtrace) %>
===================================================================
Backtrace:
===================================================================
<%= exception.backtrace.join("\n ") %>
<% end %>
EMAIL
end
end
