routes_report_generator.rb

# I found this code I wrote in an old project of mine (written around Sept 2008). The project upgraded to a new Rails version and I had to find the routes with errors.

# core extensions
class Array
  
  def bsearch_lower_boundary(key)
    range = 0 ... self.length
    lower  = range.first - 1
    upper = range.last
    while lower + 1 != upper
      mid = ((lower + upper) / 2).to_i # for working with mathn.rb (Rational)
      if (self[mid] <=> key) < 0
	      lower = mid
      else
	      upper = mid
      end
    end
    return upper
  end
  
  def bsearch_first(key)
    boundary = bsearch_lower_boundary(key)
    if boundary >= self.length || (self[boundary] <=> key) != 0
      return nil
    else
      return boundary
    end
  end
  
  def permutation(n=size)
    if size < n or n < 0
    elsif n == 0
      yield([])
    else
      self[1..-1].permutation(n - 1) do |x|
        (0...n).each do |i|
          yield(x[0...i] + [first] + x[i..-1])
        end
      end
      self[1..-1].permutation(n) do |x|
        yield(x)
      end
    end
  end
end

# Reports invalid routes due to Rails upgrade.
# Warning: This generator currently forces user to clear routes_report.txt to make sure the generator
# won't overwrite a previous report.
class RoutesReportGenerator
  
  ROUTES_REPORT_FILENAME = File.join(RAILS_ROOT, 'routes_report.txt')
  HASH_FOR_PREFIX = 'hash_for_'
  
  def initialize
    @dirs_to_scan = ["vendor/plugins/app_core/app/views",
                     "vendor/plugins/app_core/app/controllers",
                     "vendor/plugins/app_core/app/helpers"]
    @exclude_list = ["polymorphic_path", # Rails helper
                     "poly_tell_a_friend_url", "poly_comment_url", "full_url", "embed_url", "image_url", # variables
                     "infer_page_from_url", "render_path", "document_download_path", # method
                     "upload_url", "flash_url", # javascript properties
                     "new_url"] # fark.com URL parameter
    @valid_named_routes = ActionController::Routing::Routes.named_routes.names.collect {|x| x.to_s}.sort
    @found_named_routes = []
    @error_routes = []
    @fix_suggestions = []
    prepare_file(ROUTES_REPORT_FILENAME)
  end
  
  def run
    @dirs_to_scan.each do |dir_path|
      real_dir_path = File.join(RAILS_ROOT, dir_path)
      scan_directory_for_routes(real_dir_path)
    end
    generate_routes_report
  end
  
  private
  
    def scan_directory_for_routes(dir)
      all_files = File.join(dir, '**', '*')
      Dir[all_files].each do |filename|
        if File.directory?(filename)
          @dirs_to_scan << filename
        elsif File.file?(filename)
          if File.readable?(filename)
            File.open(filename) do |f|
              f.each do |line|
                # Note: cannot use the grouping parenthesis as it will mess up the scan
                matches = line.scan(/[^a-z.:_@]([a-z_]+_path|[a-z_]+_url)[^a-z_]/).flatten
                matches.each do |match|
                  check_named_route(match)
                end
              end
            end
          else
            # display warning: an unreadable file cannot be processed
          end
        end
      end    
    end
  
    def check_named_route(named_route)
      unless @found_named_routes.include?(named_route) || @exclude_list.include?(named_route)
        @found_named_routes << named_route
        unless valid_named_route?(named_route)
          @error_routes << named_route
          @fix_suggestions << suggest_valid_names(named_route)
        end
      end
    end
    
    def valid_named_route?(named_route)
      base_named_route = named_route.chomp("_path").chomp("_url")
      if @valid_named_routes.bsearch_first(base_named_route).nil?
        if base_named_route.starts_with?(HASH_FOR_PREFIX) &&
          !@valid_named_routes.bsearch_first(base_named_route[HASH_FOR_PREFIX.length, base_named_route.length-1]).nil?
          return true
        else
          return false
        end
      else
        return true
      end
    end

    def generate_routes_report
      File.open(ROUTES_REPORT_FILENAME, 'w') do |output_file|
      
        output_file.puts "OK Routes:"
        ok_routes = @found_named_routes - @error_routes
        ok_routes.each do |named_route|
          output_file.puts named_route
        end
      
        output_file.puts "\nRoutes with errors:" unless @error_routes.empty?
        
        no_suggestion_count = 0
        
        @error_routes.each_with_index do |named_route, index|
          output_file.print named_route
          
          if @fix_suggestions[index].blank?
            no_suggestion_count += 1
          else
            output_file.print " -> #{@fix_suggestions[index]}"
          end
          
          output_file.print "\n"
        end
        
        output_file.puts "\nInvalid named routes with no fix suggestion: #{no_suggestion_count}"
      
      end
    end

    def prepare_file(filename)
      raise("A non-empty #{filename} exists!") if FileTest::exists?(filename) && !(FileTest::zero?(filename))
      f = File.new(filename, 'w')
      f.close
    end
    
    def suggest_valid_names(named_route)
      words = named_route.split('_')
      # pops _path or _url out of the words
      suffix = words.pop
      
      suggestions = []
      words.uniq.permutation do |p|
        key = p.join('_')
        unless @valid_named_routes.bsearch_first(key).nil?
          suggestions << "#{key}_#{suffix}"
        end
      end
      
      suggestions.join(' ')
    end
    
end

# Notes:
# 1. script/console errors
# 2. Design script
# 3. Use Dir[].each instead of Dir.each
# 4. Scan all matches instead of 1 match per line
# 5. Use collections instead of files. Only use file for final report.
# 6. Using eval("app.#{named_route}") won't work,
#    use ActionController::Routing::Routes.named_routes.names
# 7. Convert to rake task
# 8. Add option to manually list strings to be excluded from the matching?
#    a. exclude: polymorphic_path
# 9. Suggest alternative path names
#    a. permutations of invalid named routes are checked against the list of valid ones
#    b. "hash_for_", try removing hash_for <--
# 10. Handle instance variables by matching only named routes not preceded by @

# Weird: name_prefix => nil is not working for nested map.resources