Rails代码片段

1Debugging Views in Development

ruby 代码

<!---->

<!---->
    "debug" style="margin: 40px 5px 5px 5px;">
        "#" onclick="Element.toggle('debug_info');return false" style="text-decoration: none; color: #ccc;">Show Debug Info ➲
        "debug_info" style="display : none;">
            <!---->
            <!---->

 
    还有一个相关的插件：TextmateFootnotesPlugin  
    
     ruby 代码 
     class << Dispatcher
  def dispatch(cgi = CGI.new,
               session_options = ActionController::CgiRequest::DEFAULT_SESSION_OPTIONS)
    begin
      request, response =
        ActionController::CgiRequest.new(cgi, session_options),
        ActionController::CgiResponse.new(cgi)
      prepare_application
      ActionController::Routing::Routes.recognize!(request).process(request, response).out
    rescue Object => exception
      begin
        ActionController::Base.process_with_exception(request, response, exception).out
      rescue
        # The rescue action above failed also, probably for the same reason
        # the original action failed.  Do something simple which is unlikely
        # to fail.  You might want to redirect to a static page instead of this.
        e = exception
        cgi.header("type" => "text/html")
        cgi.out('cookie' => '') do
          <<-RESPONSE



             Application Error
               #{e.class}: #{e.message}

               #{e.backtrace.join("\n")}
          RESPONSE
        end
      end
    ensure
      reset_application
    end
  end
end

  3 SQL Logging in Rails

ruby 代码

SQL_LOGGING = true
SQL_LOG_MAX_LINES = 5000
SQL_LOG_FILE = File::join(RAILS_ROOT, '/log/sql_log.txt')
# $sql_log is a global var that will hold the results of the last sql statement executed
$sql_log = ""
# permit logging if we are in development environment
if RAILS_ENV_DEV || RAILS_ENV_TEST
  connection = ActiveRecord::Base.connection
  class << connection
    alias :original_exec :execute
    def execute(sql, *name)
      # try to log sql command but ignore any errors that occur in this block
      # we log before executing, in case the execution raises an error
      begin
        if SQL_LOGGING
          if File::exists?(SQL_LOG_FILE) : lines = IO::readlines(SQL_LOG_FILE)
          else lines = Array.new(); end
          log = File.new(SQL_LOG_FILE, "w+")
          # keep the log to specified max lines
          if lines.length > SQL_LOG_MAX_LINES
            lines.slice!(0..(lines.length-SQL_LOG_MAX_LINES))
          end
          lines << Time.now.strftime("%x %I:%M:%S %p")+": "+sql+"n"
          log.write(lines)
          log.close
          $sql_log = sql
        end # if
      rescue Exception => e
        ;
      end
      # execute original statement
      original_exec(sql, *name)
    end # def execute
  end # class <<
end # if RAILS_ENV_DEV

Here's the constant setting code (put in application.rb or something it requires before the code above gets run):


class CoreERR_RailsEnvironment < StandardError; end
#RAILS specific constants
  #setup global constants for manipulating states
  RAILS_ENV_VAR = "RAILS_ENV"
  #set ENV to development if explicit or not present
  RAILS_ENV_DEV = (ENV[RAILS_ENV_VAR]=="development" || (not ENV[RAILS_ENV_VAR]))
  RAILS_ENV_LIVETEST = ENV[RAILS_ENV_VAR]=="livetest"
  RAILS_ENV_TEST = ENV[RAILS_ENV_VAR]=="test"
  if (RAILS_ENV_DEV) or (RAILS_ENV_TEST)
    RAILS_ENV_PRODUCTION = false
  else
    RAILS_ENV_PRODUCTION = true
  end
  # check positively: if production environment is implied because test and development are not found
  # but production doesn't show up positively, raise exception
  if RAILS_ENV_PRODUCTION and (RAILS_ENV_PRODUCTION != (ENV[RAILS_ENV_VAR]=="production"))
    raise CoreERR_RailsEnvironment, "Production environment implied but not detected: "+ENV[RAILS_ENV_VAR]
  end
  RAILS_DB_SU = ENV[RAILS_ENV_VAR]+'_su'
  RAILS_ENV_DEV.freeze
  RAILS_ENV_TEST.freeze
  RAILS_ENV_PRODUCTION.freeze

 

3 Digest MD5 & SHA1

Digest 支援 MD5 和 SHA1 兩種編碼, 你若有儲存密碼的需求就要用到, 一般是用 SHA1.

• MD5 計算
  

  
  require 'digest/md5'
  
  puts Digest::MD5.hexdigest("Hello World!")
  

• 計算檔案的 MD5, 可以確保檔案未曾被修改
  

  
  require 'digest/md5'
  
  #method 1
  puts Digest::MD5.hexdigest(File.read("o.rb"))
  
  #method 2
  class Digest::MD5
    def self.open(path)
      o = new
      File.open(path) { |f|
        buf = "" 
        while f.read(256, buf)
          o << buf
        end
      }
      o
    end
  end
  puts Digest::MD5.open("o.rb").hexdigest
  

• SHA1 計算
  

  
  require 'digest/sha1'
  
  puts Digest::SHA1.hexdigest("Hello World!")