DZone Snippets: Moneypenny's Code Snippets

using Event.observe for when a page loads

moneypenny () — Mon, 20 Nov 2006 20:47:53 GMT

I just prefer this implementation as opposed to window.onload.

Event.observe( window, 'load', function() {

  // Put the Javascript that needs to happen when the page

  // loads here

} );

For example, here's a way to make most of your input fields and all of your textareas have a different class when they're selected. Useful if you want to style them differently with CSS.

Event.observe( window, 'load', function() {

  var inputs = document.getElementsByTagName( 'input' );

  var textareas = document.getElementsByTagName( 'textarea' );



  for ( var i=0; i    type = inputs[i].type;



    if (

      ( type == 'button' || type == 'reset' ||

      type == 'password' || type == 'text' ||

      type == 'submit' ) &&

      ( inputs[i].onfocus == '' ||

      !inputs[i].onfocus )

    ) {

      inputs[i].onfocus = function() {

        this.className = 'selected';

      }



      inputs[i].onblur = function() {

        this.className = '';

      }

    }

  }



  for ( var i=0; i    if ( textareas[i].onfocus == '' || !textareas[i].onfocus ) {

      textareas[i].onclick = function() {

        this.className = 'selected';

      }

      textareas[i].onblur = function() {

        this.className = '';

      }

    }

  }

} );

#post method in tests with a different controller

moneypenny () — Tue, 24 Oct 2006 18:54:12 GMT

I wanted a #login method in test_helper that would allow me to easily login from any of my functional tests. However, the #post method won't allow you to set a different controller than the one in the @controller instance variable that's defined in your test's #setup. Well, by looking at how the #process method works, you can see that it just grabs the controller from @controller. Redefine that, and you're good to go:

old_controller = @controller

@controller = LoginController.new

post(

  :attempt_login,

  {:user => {:name => 'joe', :password => 'password'}}

)

@controller = old_controller

If you have several login methods, such as a #login_admin and #login_regular, you could make a wrapper to reduce duplication:

def wrap_with_controller( new_controller = LoginController )

  old_controller = @controller

  @controller = new_controller.new

  yield

  @controller = old_controller

end



def login_admin

  wrap_with_controller do

    post(

      :attempt_login,

      {:user => {:name => 'root', :password => 'password'}}

    )

  end

end



def login_regular

  wrap_with_controller do

    post(

      :attempt_login,

      {:user => {:name => 'joe', :password => 'password'}}

    )

  end

end

classify() for alternating rows, columns, etc.

moneypenny () — Fri, 08 Sep 2006 21:00:13 GMT

I often want different rows in a table to alternate in color, and I do this by assigning each row a class name and styling it with CSS. This is a simple helper method designed to return a class name based on the given row count.

It is also convenient for me to assign a class to table cells based on the type of content they hold. For example, if I have a cell with a float value in it, I want to display it with a monospace font, whereas if I have a cell with a string in it, I want to display it in a serif font.

# Determines the CSS class based on either the count given

# (returns 'even' or 'odd' as the CSS class name) or the class

# given (returns the string version of the class, lowercased,

# as the CSS class name)

def classify( count_or_class, include_class_text = true )

  if count_or_class.class == Fixnum

    value = ( count_or_class % 2 == 0 ? 'even' : 'odd' )

  else

    value = count_or_class.to_s.downcase

  end



  if include_class_text

    'class="' << value << '"'

  else

    value

  end

end

Example usage with alternating 'even'/'odd' row class names:


<% count = 0 %>

<% @collection.each do |value| %>

>



  <% count += 1 %>

<% end %>


      <%=h value %>

Example usage with data type class names:



<% @columns.each do |column| %>

  <% data = row.send( column.name ) %>

  >

    <%=h data %>

  

<% end %>

helper to determine if radio/checkbox needs to be checked

moneypenny () — Thu, 07 Sep 2006 16:25:27 GMT

I frequently have to use methods such as 'radio_button' and 'check_box_tag' when I don't have an object with a method that will automatically determine the value of the input field. Therefore, I have to check to see if a certain parameter has been passed, and if so, if the parameter's value matches that of the input's value. This method does that.

It's designed to be used in a Rails helper. You can either pass it the object, method, and value (the same parameters as, for example, radio_button) or name and value (the same parameters as radio_button_tag).

def checked?( *args )

  if args.length == 3

    object, method, value = args

    if params[object] && params[object][method] && params[object][method] == value

      'checked'

    end

  elsif args.length == 2

    name, value = args

    if params[name] && params[name] == value

      true

    end

  end

end

Here's an example usage:
<%= radio_button 'person', 'age', '12', :checked => checked?( 'person', 'age', '12' ) %>

If params[:person][:age] exists and it equals '12', then 'checked?' returns 'checked'; otherwise, it returns nil.

conditioner for ActiveRecord-friendly conditions from a collection

moneypenny () — Thu, 31 Aug 2006 22:02:52 GMT

I frequently have a collection of values that I want to match in an ActiveRecord query, but it would be nice if I could let ActiveRecord handle checking the data and escaping it properly. So, I wrote this method to return ActiveRecord-friendly conditions, such as: ["user_id=? AND job_id=?", 3, 4] based on the 'raw' conditions you feed to it, such as: [['user_id', 3], ['job_id', 4]]

# Returns ActiveRecord-friendly conditions based on the given

# raw conditions; handles grouping based on like field names;

# allows different boolean operators in raw conditions;

# allows different comparison operators in raw conditions;

# raw conditions setup:

# [[field name, desired value, bool. op., comp. op.], ...]

# name = condition[0]

# value = condition[1]

# bool_type = condition[2]

# comparison = condition[3]

# raw conditions example:

# [['type_id', '4', 'OR'], ['created_on', Date.new, 'AND', '<=']]

def conditioner( raw_conditions )

  return nil if raw_conditions.nil? || raw_conditions.empty?

  

  conditions = ['(']

  count = 0

  prev_name = raw_conditions[0][0]

  raw_conditions.each do |condition|

    name = condition[0]

      

    conditions[0] << ') AND ' if prev_name != name

    conditions[0] << ' ' << ( condition[2] || 'OR' ) << ' ' unless count == 0 || prev_name != name

    conditions[0] << '(' if prev_name != name

    conditions[0] << name + ' ' << ( condition[3] || '=' ) + ' ?'

      

    conditions << condition[1]

      

    prev_name = name

    count += 1

  end

  conditions[0] << ')'



  conditions

end

This way, you can do something like the following:

model_ids = Model.find( :all ).map( &:id )

raw_conditions = model_ids.collect { |id| ['model_id', id] }

conditions = conditioner( raw_conditions )

desired_collection = OtherModel.find( :all, :conditions => conditions )

If your query needs to depend on more than one factor, you might do something like the following:

if test

  raw_conditions = [['user_id', 3]]

else

  raw_conditions = [['user_id', 4], ['groups.name', 'dev']]

end



team_ids.each { |id| raw_conditions << ['team_id', id, 'AND'] }

go from model to associated table name and back

moneypenny () — Sat, 03 Jun 2006 00:50:06 GMT

Given a table object, it returns the related string object; e.g. SubAttribute => 'sub-attribute'. Useful if you want to make a list of all your tables with perhaps their fields listed out to the side.



def stringify_table( table, replace_char = '-', pluralize = false )

  string = table.to_s.gsub( /([A-Za-z])([A-Z])/, '\1' << replace_char.to_s << '\2' )

  string = string.pluralize if pluralize

  string

end

Given a string akin to the name of a table, it returns the related table object; e.g. 'sub_attributes' => SubAttribute.



def tablify_string( string )

  eval( string.to_s.gsub( /_id/, '' ).singularize.split( '_' ).collect { |word| word.capitalize }.join )

end