rename_images.rb

require 'image_size' #imagesize.rubyforge.net

=begin

This is a small test script that I wrote to play around with Ruby's directory
and file handling.

The scenario is this... I have a directory structure as follows:

/rename.rb
/testing
        /merchant1
                  /logo.jpg
                  /logo_homepage.jpg
                  /logo_landing.jpg
        /merchant2
                  /logo.jpg
                  /logo_homepage.jpg
                  /logo_landing.jpg        
        /merchant3
                  /logo.jpg
                 /logo_homepage.jpg
                  /logo_landing.jpg
        /etc..                
        
The goal is to go through each directory (the directory structure is standard,
so there's no need for recursion) and test each JPEG image from the hash 
(files_to_rename) for proper width.  If the width is correct (as defined in 
the hash), then rename it to the new name as defined in the hash.

=end

# Directory we're using
directory = 'C:/ruby_projects/file_rename/testing/'

# Files to exclude from the directory listing
files_to_exclude = ['.','..']

# Files that we're testing and name changing
files_to_rename = { 
  # current filename => [new filename, required img width]
  'logo.jpg' => ['logo_300.jpg',300],
  'logo_homepage.jpg' => ['logo_280x45.jpg',280],
  'logo_landing.jpg' => ['logo_728x90.jpg',728]
}

# Get the directory list
Dir.chdir(directory) # Navigate to directory
directory_listing = Dir.entries('.') # Get directory listing
directory_listing.delete_if {|fn| files_to_exclude.include?(fn) } # Delete excluded files
directory_listing.delete_if {|fn| !File.directory?(fn) } # Delete non-directories

# Process each directory
directory_listing.each do |dir|

  # Navigate to dir
  Dir.chdir(directory + '/' + dir + '/')
  
  # Get all the .jpg files from dir
  images = Dir.glob('*.jpg')
  
  # Begin renaming logic
  images.each do |img|
    
    # Check if we're trying to rename this particular image
    if files_to_rename.include?(img)
      
      # Get the image's dimensions
      raw_img = File.open(img,'rb') {|i| i.read } # Open image
      img_size = ImageSize.new(raw_img).get_size # Get image dimensions

      # Check the width to make sure it's correct
      if files_to_rename[img][1] == img_size[0]
        
        # The width is correct, so rename it as desired
        File.rename(img,files_to_rename[img][0])
      
      else
        
        # Width doesn't match, so rename with a flag for manual resizing
        File.rename(img,'RESIZE_' + files_to_rename[img][0])
      
      end
      
    end
    
  end
  
end