Category: software development

So often in Ruby on Rails I find myself needing to convert a variable to a Boolean, and there is no built in way of doing it. So, how about this:

class Boolean
  def self.parse(obj)
    %w(true t 1 y).include?(obj.to_s.downcase.strip)
  end
end

We use this at work and it’s a nice neat way of ensuring non-repetitive code reuse :)

For a Salesforce.com integration project, I need to create a SOAP server to accept messages from Salesforce. Seeing as there is no way directly import a wsdl into ActionWebService, I instead used wsdl2ruby from the soap4r distribution to generate server stubs. Then, I used ActionWebService to emulate the same service. I had problems with using the default layout, so I changed my structure to use a delegated structure:

class NotificationServiceController < ApplicationController
  web_service_dispatching_mode :delegated
  web_service_scaffold :invoke
  web_service :notifications, NotificationService.new
end

class NotificationServiceApi < ActionWebService::API::Base
  inflect_names false
  require_soap_action_header false
  api_method :notifications,
             :expects => [Notifications],
             :returns => [:bool]
end

class NotificationService < ActionWebService::Base
  web_service_api NotificationServiceApi
  def logger
    RAILS_DEFAULT_LOGGER
  end
  def notifications(organization_id, action_id, session_id, enterprise_url, partner_url, notification)
    my_object_id = notification.sObject.id
    ack = false
    begin
      ack = so_something(my_object_id)
    rescue Exception => e
      logger.error("Error processing payment: #{e.message}")
    end
    ack
  end
end

But STILL SOMETHING WAS WRONG. I was getting "No valid method call - missing method name" with the Salesforce outbound message queue reporting "org.xml.sax.SAXParseException: Content is not allowed in prolog." MMmmmmm helpful. The stack trace was showing that rails was trying to process the request as XMLRPC not SOAP, which was all wrong.

The stack trace looked something like this:

RuntimeError (No valid method call - missing method name!):
    /usr/lib/ruby/1.8/xmlrpc/parser.rb:476:in `parseMethodCall'
    /usr/lib/ruby/1.8/xmlrpc/marshal.rb:63:in `load_call'
    /usr/lib/ruby/1.8/xmlrpc/marshal.rb:32:in `load_call'
    /vendor/rails/actionwebservice/lib/action_web_service/protocol/xmlrpc_protocol.rb:36:in `decode_request'
    /vendor/rails/actionwebservice/lib/action_web_service/protocol/xmlrpc_protocol.rb:32:in `decode_action_pack_request'
    /vendor/rails/actionwebservice/lib/action_web_service/protocol/discovery.rb:20:in `discover_web_service_request'
    /vendor/rails/actionwebservice/lib/action_web_service/protocol/discovery.rb:18:in `discover_web_service_request'
    /vendor/rails/actionwebservice/lib/action_web_service/dispatcher/action_controller_dispatcher.rb:49:in `dispatch_web_service_request'
    (eval):1:in `notifications'
..........

Then, I came across patch 7077 (indirectly via this and then this), so, using my new best friend Piston I checked out Rails 1.2.3 into vendor/rails, and patched with the diff in the change. It was not entirely smooth - the xmlrpc.rb file could not be patched, but I merged the change manually.

All done! Works!

One thing I did discover the hard way though is that you need to have the whole stack of definitions with the same naming scheme for this to work. That is, if you've got a NotificationServiceController, you need to ensure that you have a NotificationService and a NotificationServiceApi defined and in use - no other class names will work. No Reuse of API Definitions, which is a bit of a bugger.

Over the weekend I decided to try (again) to find a Rails plugin for a Dhtml Calendar. The previous one I tried relied on an Engine, and for some totally unreasonable errrrrrrrr reason, I don’t like that. So I came across this: http://dry.4thebusiness.com/info/dhtml_calendar. At first it was all sunshile, lollipops and rainbows, but I soon realised that the plugin did not like Firefox.

This was, of course, a right pain. A quick test in IE determined it worked fine. In Firefox, it popup worked, but when you select a date the select boxes did not get updated. I waded through the javascript that comes with the plugin, and it seemed ok, but it simply WAS NOT firing in Firefox.

After some Javascript mangulation (that’s my word but you can use it if you want) I figured out that it wasn’t picking up the HTML form. So, even though the documentation says:

“Note: :form_name is optional unless your form is named. If it is named then supply the name of the form.”

I included it anyway.

And it worked. Yay.

Also, in the past I have used svn:externals to include external plugin into my project, and at the most inopportune time the external site as either (and I have had both of these happen):

1. The external site is inaccessible at deployment time, meaning that your site is offline, or
2. The external site updates the codebase to suit a new Rails version that you have not upgraded to, meaning that your site is broken and once again, offline

After doing that once or twice, I gave up on svn:externals and just exported the remote source and checked it into my repository, which is a bit shit because it removes the link to the origin of the code. This time I used Piston.

Piston fixes this. It checks out the remote code as an svn export but it stores the synchronization information as svn properties so that it can later be updated, or locked, or even merge the remove changes wth your own changes. Spiffy!