Category: GNU/Linux

Suppose we have created a ‘BlogPost’ Model in Rails and it have the following fields in a blog post:

title – title of the blog post
posted_on – date posted
permalink – a permanent link of each blog post (act as a primary key)
publish – a boolean field which decides the post need to show or not

Lets write a method in ‘BlogPost’ Model to get a recent list of posts.
Pass a ‘months_old’ parameter to determine how much months old posts we wanted to list.
Just select the required columns to show the details of the post (by ‘:select => ‘). And Group each post by posted month.

  def self.get_recent_months_post(months_old)
    @blog_posts = where("publish = ? AND posted_on > ?", true, Date.today - months_old.months).all(:select => "title, posted_on, permalink", :order => "posted_on DESC")
    (@blog_posts.group_by { |t| t.posted_on.beginning_of_month }).sort.reverse
  end

We successfully written the method above. Now lets write a method to get the archives (old posts).

  def self.get_archives(old)
    @blog_posts = where("publish = ? AND posted_on  "title, posted_on, permalink", :order => "posted_on DESC")
    (@blog_posts.group_by { |t| t.posted_on.beginning_of_month }).sort.reverse
  end

If we have some keys and values and we just need to create a url with this data just pass the url and hash as a parameter to the following method.

def generate_url_with_params(url, params = {})
    uri = URI(url)
    uri.query = params.to_query
    uri.to_s
end

If you want to get rid of the parameters from a url use the following method.

  def generate_url_without_params(url, params = {})
    uri = URI(url)
    full_params = Rack::Utils.parse_query uri.query
    params.each do |key, val|
      full_params.delete key
    end
    uri.query = full_params.to_param
    uri.to_s
  end

When I was working with rails and paperclip I got this error.

Paperclip::AdapterRegistry::NoHandlerError

 = form_tag my_path, :method => :post do
  -------
  = file_field_tag "attachment" 
  -----
 

I submitted a form and it was not saving. There I found that the form sending a file too. I missed

:multipart => true 

option in the ‘form_tag’ when submitting the form. The form really not sening a file and paperclip not getting an attachment. So it throws this error.

 = form_tag my_path, :method => :post, :multipart => true do
  -------
  = file_field_tag "attachment" 
  -----