Module: DT

Defined in:
lib/dt.rb,
lib/dt/action_controller_extensions.rb

Overview

Debug toolkit.

Allows to print debug messages from anywhere in your Rails project. Do a:

DT.p "Hello, world!"

, and see the message in log, log/dt.log, console and web.

To set up web output, in your application root do a:

$ rails generate rails_dt     # Rails 3
$ script/generate rails_dt    # Rails 2

Follow the instructions the generator gives you then.

Defined Under Namespace

Modules: ActionControllerExtensions

Constant Summary collapse

MAX_WEB_MESSAGES =

Maximum number of stored messages, if they’re not cleared. If web output is configured, messages are cleared before every request.

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Class Method Summary collapse

Class Method Details

._hash_kbinding(h) ⇒ Object

Turn hash’s entries into locals and return binding. Useful for simple templating.



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# File 'lib/dt.rb', line 212

def self._hash_kbinding(h)    #:nodoc:
  # NOTE: This IS important, since assignment is eval'd in this context.
  bnd = binding

  _value = nil
  h.each do |k, v|
    ##puts "-- k-#{k.inspect} v-#{_value.inspect}"    #DEBUG
    _value = v      # IMPORTANT: Ruby 1.9 compatibility hack.
    eval("#{k} = _value", bnd)
  end

  bnd
end

._initialize ⇒ Object

Initializer.



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# File 'lib/dt.rb', line 26

def self._initialize    #:nodoc:
  clear_web_messages

  # NOTES:
  # * Stuffing is inserted in order to work around buggy RDoc parser.
  #   "a""bc" => "abc", just in case.
  # * Don't forget to update generator/initializers/dt.rb with these.
  # * "Canonical" order of imporance: log, console, web.
  @log_prefix = "[DT <""%= file_rel %>:<""%= line %>] "
  @console_prefix = @log_prefix.dup
  @web_prefix = '<a href="txmt://open?url=file://<''%= file %>&line=<''%= line %>"><''%= file_rel %>:<''%= line %></a> '

  # In case of path problems @log will be nil.
  @log = Logger.new(Rails.root + "log/dt.log") rescue nil
end

._otf_init ⇒ Object

On-the-fly initializer.



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# File 'lib/dt.rb', line 43

def self._otf_init    #:nodoc:
  # Consider job done, replace self with a blank.
  class_eval {
    def self._otf_init    #:nodoc:
    end
  }

  _initialize
end

.clear_web_messages ⇒ Object

Clear messages.



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# File 'lib/dt.rb', line 125

def self.clear_web_messages
  _otf_init
  @web_messages = []
end

.console_prefix ⇒ Object 



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# File 'lib/dt.rb', line 59

def self.console_prefix
  _otf_init
  @console_prefix
end

.console_prefix=(s) ⇒ Object

Set message prefix for console. See log_prefix=.



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# File 'lib/dt.rb', line 54

def self.console_prefix=(s)
  _otf_init
  @console_prefix = s
end

.log ⇒ Object 



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# File 'lib/dt.rb', line 73

def self.log
  _otf_init
  @log
end

.log=(obj) ⇒ Object

Set logger to use. Must be a Logger.

log = Logger.new("log/my.log")



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# File 'lib/dt.rb', line 67

def self.log=(obj)
  _otf_init
  raise "Logger expected, #{obj.class} given" if not obj.is_a? Logger
  @log = obj
end

.log_prefix ⇒ Object 



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# File 'lib/dt.rb', line 100

def self.log_prefix
  _otf_init
  @log_prefix
end

.log_prefix=(s) ⇒ Object

Set message prefix for log. Syntax is ERB.

log_prefix = "[DT <""%= file_rel %>:<""%= line %>] "

NOTE: In the above example some stuffing was made to satisfy the buggy RDoc parser. Just in case, "a""bc" is "abc" in Ruby.

Template variables:

  • file – full path to file.

  • file_base – file base name.

  • file_rel – file name relative to Rails application root.

  • line – line number.

By setting prefix to nil you disable respective output.

web_prefix = nil      # Disable web output.



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# File 'lib/dt.rb', line 95

def self.log_prefix=(s)
  _otf_init
  @log_prefix = s
end

.p(*args) ⇒ Object

Print a debug message or dump a value. Somewhat similar to Ruby’s native p.

p "Hello, world!"
p "myvar", myvar



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# File 'lib/dt.rb', line 134

def self.p(*args)
  _otf_init
  # Fetch caller information.
  # NOTE: May be lacking file information, e.g. when in an irb session.
  file, line = caller.first.split(":")

  # Assign template variables.
  hc = {
    :file => file,
    :line => line,
    :file_base => (begin; File.basename(file); rescue; file; end),
    :file_rel => (begin; Pathname(file).relative_path_from(Rails.root).to_s; rescue; file; end),
  }

  args.each do |r|
    s = r.is_a?(String) ? r : r.inspect

    # To log.
    if @log_prefix
      ##Kernel.p "@log", @log   #DEBUG
      if @log
        pfx = ERB.new(@log_prefix, nil, "-").result(_hash_kbinding(hc))
        msg = [pfx, s].join
        @log.info msg
        Rails.logger.info msg rescue nil    # In case something's wrong with `Rails.logger`.
      end
    end

    # To console.
    if @console_prefix
      pfx = ERB.new(@console_prefix, nil, "-").result(_hash_kbinding(hc))
      puts [pfx, s].join
    end

    # To web.
    if @web_prefix
      pfx = ERB.new(@web_prefix, nil, "-").result(_hash_kbinding(hc))

      pcs = []
      pcs << pfx
      pcs << CGI.escapeHTML(s).gsub("\n", "<br/>\n")
      @web_messages << pcs.join

      # Rotate messages.
      @web_messages.slice!(0..-(MAX_WEB_MESSAGES + 1))
    end
  end

  # Be like `puts`, return nil.
  nil
end

.web_messages ⇒ Object

Return messages accumulated since last cleared.



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# File 'lib/dt.rb', line 106

def self.web_messages
  _otf_init
  @web_messages
end

.web_messages_as_html ⇒ Object

Format accumulated web messages as HTML. Usually called from a view template.

web_messages_as_html    # => Something like "<ul><li>Message 1</li><li>Message 2</li>...</ul>".



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# File 'lib/dt.rb', line 189

def self.web_messages_as_html
  _otf_init

  pcs = []
  pcs << "<ul>"
  @web_messages.each do |s|
    pcs << ["<li>", s, "</li>"].join
  end
  pcs << "</ul>"

  if (out = pcs.join).respond_to? :html_safe
    out.html_safe
  else
    out
  end
end

.web_prefix ⇒ Object 



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# File 'lib/dt.rb', line 117

def self.web_prefix
  _otf_init
  @web_prefix
end

.web_prefix=(s) ⇒ Object

Set message prefix for web. See log_prefix=.



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# File 'lib/dt.rb', line 112

def self.web_prefix=(s)
  _otf_init
  @web_prefix = s
end