ActiveRecord: Can't Retrieve value of Id after insert

Although there could be many problems (for example the record isn't actually saving), another problem I ran into is that you need to be using naming conventions. I was using 'Id' for my primary field name. That didn't work. Tried it with 'id' and everything began working well again.

Problem subtracting dates minus_without_duration

If you try subtracting dates that are really large (like in the year 2499) you will get the error minus_without_duration. make the dates more reasonable and everything works just fine.

Rails Reserved Words

if you use words from this list as your column names you will get all kinds of grief and heartache. Be careful:

The only list I've found that had all the words I've run into problems with is here:

http://www.yup.com/articles/2007/01/31/no-reservations-about-keywords-in-ruby-on-rails

Custom sql query with Activerecord

LabourEntry.all(:conditions => [sql])

Migrations

Docs for adding and removing columns

http://api.rubyonrails.org/classes/ActiveRecord/Migration.html

Uninitialized Constant error on Controller

If for whatever reason you have screwed up your controller names by having singular where you should have plural or whatever, you can correct this problem through your routes file. here's a quote that helped me fix a problem with restful_authentication plugin.



for those people that used a singular Session and get the "uninitialized constant SessionsController"

So instead of
map.resource :session
use rather
map.resource :session, :controller => 'session'

Adding Restful_Authentication to all controllers (by placing in application controller)

In short add

before_filter :login_required

to ApplicationController. Then throw in an exception in SessionsController that says

before_filter :login_required, :except => [:new, :create, :destroy]

Here's the excerpt from:

http://www.erikjacobs.com/2008/12/03/authenticating-all-controllers-for-your-rails-application-with-restful_authentication/

So while this might seem intuitive, I found it a little tricky. Preliminary Google searching didn’t reveal anything inherently obvious. However, robbrit on Freenode was able to lend me a hand and I got it figured out.

As you might expect, restful_authentication’s before_filter, :login_required, will direct you to the sessions controller if you are not logged in. So, I initially applied this before_filter to the entire application by placing it as the first line in app/controllers/application_controller.rb

class ApplicationController < ActionController::Base
  before_filter :login_required

Unfortunately, this had unintended consequences. Because this requires login for *all* controllers and *all* actions, we find that we are caught in an endless loop. The login route sends us to /sessions/new, but since we are not logged in, this action tries to again send us to login. Oops!

Rails is kind enough to allow for some exceptions and other fun with filters. So, I initially realized that we should probably add an exception for the “new” action, since that is where we are redirected for a login. We add this exception by re-iterating the before_filter in the app/controllers/sessions_controller.rb:

class SessionsController < ApplicationController
  before_filter :login_required, :except => :new

Unfortunately, this did not quite cut it entirely. Do not forget that the new action essentially just renders the login form. The create action is where all of the *real* work is done. But, since we did not except create, we end up in a login loop. We can fill out the form, press the “login” button, but when we reach the create action we are not logged in. This causes the filter to fire off and send us back to… you guessed it… the new action.

Adding an additional exception (and destroy, just in case) provides the results we are looking for:

class SessionsController < ApplicationController
  before_filter :login_required, :except => [:new, :create, :destroy]

Hopefully all of this stuff will work for you, too. This is just one way I found to authenticate all controllers with restful_authentication as I had a particular application that we wanted to lock down. The extra fun with this type of stuff is that you could put a before_filter on the signup actions. This would have the effect of only allowing a user with an existing account to create new users. This is useful for development lockdown to a certain extent.