Merb and Chronic: Natural Language Date Parsing

This assumes you’ve already got started with merb, and that you are using datamapper as your orm.

NOTE: This DOESN’T validate the chronicfied date yet so strange words like gobblygoob will still get passed, and the form will get saved.

0.Install chronic gem

sudo gem install chronic

1. In init.rb make sure you include the chronic gem as well as the following gems.

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dependencies "merb-more", "merb_helpers", "merb-assets", "dm-timestamps", "dm-validations", "chronic"

2. In your model.rb chronicfy the date with the datamapper before_valid? hook

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  class Post
  include DataMapper::Resource
 
  property :id, Integer, :serial => true # A :serial property is an auto-incrementing key
  property :date, Date
  property :title, :String
  property :description, String
  property :created_at, DateTime
  property :updated_at, DateTime
 
  # see http://datamapper.org/docs/validations.html though there must be a way to refactor this cleaner
  validates_with_method :must_be_chronic
  def must_be_chronic
    if Chronic.parse(self.date).nil?
      [false, "is not a valid date. Try removing any commas."]
    else
      return true
    end
  end
 
  before :valid?, :chronicfy
  def chronicfy 
    self.date = Chronic.parse(self.date)
  end
 
end

3. In your view, change the date field to a text_field.

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<h1>Posts controller, new action</h1>
 
<p>Edit this file in <tt>app/views/posts/new.html.erb</tt></p>
 
<%= form_for @post, :class => "post_form", :action => url(:posts) do %>
	<%= partial("posts/form") %>
<% end =%>
 
 
# here's the _form.rhtml partial
<%= error_messages_for @post %>
 
<p>
<%= text_field :date, :label => "Date<br />" %>
</p>
 
<p>
<%= text_field :title, :label => "Title<br />" %>
</p>
 
<p>
<%= text_field :description, :label => "Description<br />" %>
</p>

No Comments | September 11, 2008

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