Add support for MySQL column positioning via #add_column and #change_column

add_column and change_column in the MySQL adapter now accept some additional options:

:first => true # Put the column in front of all the columns

:after => column_name # Put the column after 'column_name'

clas...

One important thing to remember is that this is NOT hidden in the source code and can be modified by an evil user so all input in a hidden field should be considered as untrustworthy and checked just like a visible field.

Note that save() only returns false on validation errors (when valid? returns false). If other errors occur at the database level, like a database deadlock or trying to insert null into a column that doesn't allow it, that will still raise an exception.

You can use this excellent library to stub Net:HTTP connections in your automatic tests:

http://github.com/bblimke/webmock

One of the common ways of using fragment caching is to cache content that's shared across the site (eg. left navigation, menus, widgets etc.) that looks and works the same regardless of the name of the action or controller calling it. In such cases it's very easy to just use named fragment caching e...

Resources are added after the :path_prefix. However if you use a :path_prefix on a resource, it overrides the namespace path instead of appending to it (as I think it should).

Here is what I wrote to create a versioned API access path.

map.namespace :api3, :path_prefix=>"/api/v3" do |api| api....

If you want to prevent a specific group of tests from being run inside a transaction, just define inside your test class the methods teardown_fixtures and setup_fixtures with empty bodies.

If you want to prevent a specific group of tests from being run inside a transaction, just define inside your test class the methods teardown_fixtures and setup_fixtures with empty bodies.

If you're trying to calculate 2 to the power of 2, the ^ method is not what you want. Try ** instead.

2^2  #=> 0
2^8  #=> 10
2**2 #=> 4
2**8 #=> 256

It's not possible to use Array methods with a scope because it's not an Array but an ActiveRecord::NamedScope::Scope :

this Article.promotion.sum(&:price) doesn't run.

But you can use the to_a method to transform the ActiveRecord::NamedScope::Scope to an Array :

Article.promotion.to_a.sum...

class Hash
def has_keys?(*_keys)
  (_keys - self.keys).empty?
end
end

h = {1=>'a',2=>'b'}

h.has_keys?(1,2) #-> true

h.has_keys?(1,3) #-> false

A warning note (at least for v2.3.4): if you don't use the yielded format object, you will get a cryptic error like this:

NoMethodError (You have a nil object when you didn't expect it! The error occurred while evaluating nil.call): app/controllers/comments_controller.rb:11:in `create'

So...

While it renders to the same rules as render, you need to specify params.

You'd think this would work: render_to_string "users/profile", :layout => false

You need to do this instead render_to_string(:layout => "users/profile", :layout => false)

Be aware that has_and_belongs_to_many saves association to join table immediately after assign. It does NOT wait for my_object.save. Hence if save does not get through validations (or fail for any other reason), associated records will still be in the database.

Here is a nice workaround: http://git...

As pointed out below, you can also have optional parameters. But you will get something like "warning: multiple values for a block parameter (0 for 1)" if you omit them.

You can avoid those warnings by passing *args and picking the parameters yourself:

define_method :tha...

If you have set ActiveRecord::Base.include_root_in_json = true, then when you do .to_json on an object, the output will begin with the class name rather than just a hash of attributes.

==== from the rails docs konata = User.find(1) ActiveRecord::Base.include_root_in_json = true konata.t...

This method changes the object/array the method is called on. For example:

a = ["a", "b", "c"]
b = ["x", "y", "z"]

a.concat(b)  #=> [a", "b", "c", "z", "y", "z"]
a #=> [a", "b", "c", "z", "y", "z"]

In this example the object A is modified, the method modifies the object, then re...

If You're seeing a Net::SMTPFatalError (555 5.5.2 Syntax error ...) than You should check the email's from header ! You probably have brackets while calling the from attribute setter :

=== Works in Rails < 2.3.3

def signup_notification(recipient)
  recipients      recipient.emai...

One can not invoke render twice during an action. Thus if You have a complicated rendering logic but at the end would like to render some default content, or just would like to find out whether render has been called during the current action, use performed?. This also works with "empty" ren...

Remember, format blocks set the response's content type. This can present problems when handling errors.

class MediaController rescue_from ActionController::MissingFile do |e| # User's browser probably wont display this # Content-Type is application/x-shockwave-flash render :f...