Ruport, Rails, PDFs and Column Alignment/Justification

I'm currently working on a Rails project that needs to generate Report PDFs. Ruport, of course, is an obvious choice for this task. It took me a little bit to get used to how Ruport does things (read: wants you to do things). I don't want to dive too deep into getting started with Ruport. If you're new to it, check out these two great guides: The Dimwit's Guide and O'Reilly Network Ruport Guide. Please note, however, that the tutorials and guides often mention "Renderers": they are called "Controllers" in the current version of Ruport. Just keep that in mind. So back to my PDF columns problem: I wanted to be able to have all the text in the first column left-aligned and the text in all the other columns right-aligned. This turned out to be a little harder than I thought. Let's do this step by step (I assume you have installed the Ruport Gem and it's dependencies). This will also show you how to use Ruport in your Rails app without acts_as_reportable:

1. Create a "reports" directory inside your app directory.
2. Add it to your Rails load path by adding this inside the Rails::Initializer.run block in your environment.rb:

   config.load_paths += %W( #{RAILS_ROOT}/app/reports )

3. For the next step, we assume to have class that looks something like this:

   class MyReport < ActiveRecord::Base
     validates_presence_of :report_title, :report_subtitle
   
     # ColumnHeader has an attribute "name"
     has_many :column_headers
   
     # We assume they come in the right order, and a row has_many columns.
     # A Column has an attribute "value"
     has_many :rows
   end
   

   So we see our report can have n rows with n columns and two attributes: "report_title" and "report_subtitle".
4. Create a file called "my_report_renderer.rb" in your app/reports directory.
5. Put this in the file:

   require 'ruport'
   
   class MyReportRenderer < Ruport::Controller
     stage :report_header, :report_body
     finalize :report
   
     class PDF < Ruport::Formatter::PDF
       renders :pdf, :for => MyReportRenderer
   
       def build_report_header
         # data is an instance of your MyReport class
         add_text "My Great Report", :font_size => 20,
                 :justification => :center
         add_text data.report_title, :font_size => 18
         add_text data.report_subtitle, :font_size => 16
       end
   
       def build_report_body
         # we have to build the table
         headers = []
   
           
         # gather the column header strings in an array
         data.column_headers.each do |ch|
           headers << ch.name
         end
   
   
         table = Table(headers) do |t|
           data.rows.each do |row|
             columns = []
   
             # gather the actual column values for each row in an array       
             row.columns.each do |col|
               columns << col.value
             end
   
             # add the columns for the current row to the table
             t << columns
           end
         end
   
         # create column option that right justify all columns but the first one
         col_opts = {}
         header_index = 0
         for header_index in (0..(headers.length - 1))
           # we'll skip the first one, since :left is the default
           if header_index != 0
             # the options for each column are indexed by it's name (headers array)
             col_opts[headers[header_index]] = {:justification => :right}
           end
         end
   
         pad (20) { draw_table(table, :column_options => col_opts) }
       end
   
       def finalize_report
         render_pdf
       end
     end
   end

   OK, now we have a renderer (or controller) that renders our report with all columns right-justified except for the first one.
6. Now just add an action to your MyReport Rails controller:

   def download_pdf
     begin
       @report = MyReport.find(params[:id]) 
       send_data(MyReportRenderer.render(:pdf, :data => @report),
             :filename => "report#{params[:id]}.pdf",
             :type => "application/pdf",
             :disposition => 'inline')
     rescue ActiveRecord::RecordNotFound
       flash[:error] = "Report not found."
       redirect_to :action => :index
     end
   end

7. That's it.

I didn't actually try this code: it's modified (simplified) code from the app I'm working on, but it should work. If not, please leave a comment.

If this was useful for you, please take a minute and recommend me: Thank you!