Module: Arrow::HTMLUtilities

Included in:: HtmlInspectableObject, Logger::ArrayOutputter, Logger::HtmlOutputter, Service, Template::Node
Defined in:: lib/arrow/mixins.rb

Overview

A collection of HTML utility functions

Constant Summary

THREAD_DUMP_KEY = The name of the Thread-local variable to keep the serialized-object cache in (i.e., Thread[ THREAD_DUMP_KEY ] = {}). The cache is keyed by object_id

:__to_html_cache__

HASH_HTML_CONTAINER = The HTML fragment to wrap around Hash objects

%{<div class="hash-members">%s</div>}

HASH_PAIR_HTML = The HTML fragment to use for pairs of a Hash

%{<div class="hash-pair %s">\n} +
%{<div class="key">%s</div>\n} +
%{<div class="value">%s</div>\n} +
%{</div>\n}

ARRAY_HTML_CONTAINER = The HTML fragment to wrap around Array objects

%{<ol class="array-members"><li>%s</li></ol>}

IMMEDIATE_OBJECT_HTML_CONTAINER = The HTML fragment to wrap around immediate objects

%{<div class="immediate-object">%s</div>}

OBJECT_HTML_CONTAINER = The HTML fragment to wrap around objects other than Arrays and Hashes.

%{<div id="object-%d" class="object %s">%s</div>}

IVAR_HTML_FRAGMENT = The HTML fragment to use for instance variables inside of object DIVs.

%Q{
  <div class="%s">
  <div class="name">%s</div>
  <div class="value">%s</div>
  </div>
}

Instance Method Summary

- (Object) escape_html(string)
Escape special characters in the given string for display in an HTML inspection interface.
- (Object) make_html_for_object(object)
Return an HTML fragment describing the specified object.
- (Object) make_object_html_wrapper(object)
Wrap up the various parts of a complex object in an HTML fragment.

Instance Method Details

- (Object) escape_html(string)

Escape special characters in the given string for display in an HTML inspection interface. This escapes common invisible characters like tabs and carriage-returns in additional to the regular HTML escapes.

# File 'lib/arrow/mixins.rb', line 170

def escape_html( string )
  return "nil" if string.nil?
  string = string.inspect unless string.is_a?( String )
  string.
    gsub(/&/, '&amp;').
    gsub(/</, '&lt;').
    gsub(/>/, '&gt;').
    gsub(/\n/, '&#8629;').
    gsub(/\t/, '&#8594;')
end

- (Object) make_html_for_object(object)

Return an HTML fragment describing the specified object.

# File 'lib/arrow/mixins.rb', line 183

def make_html_for_object( object )
  return object.html_inspect if 
    object.respond_to?( :html_inspect ) && ! object.is_a?( HtmlInspectableObject )
  object_html = []

  case object
  when Hash
    object_html << "\n<!-- Hash -->\n"
    if object.empty?
      object_html << '{}'
    else
      object_html << HASH_HTML_CONTAINER % [
        object.collect {|k,v|
          pairclass = v.instance_variables.empty? ? 
            "simple-hash-pair" :
            "complex-hash-pair"
          HASH_PAIR_HTML % [
            pairclass,
            make_html_for_object(k),
            make_html_for_object(v),
            ]
        }
      ]
    end

  when Array
    object_html << "\n<!-- Array -->\n"
    if object.empty?
      object_html << '[]'
    else
      object_html << ARRAY_HTML_CONTAINER % [
        object.collect {|o| make_html_for_object(o) }.join('</li><li>')
      ]
    end

  else
    if object.instance_variables.empty?
      return IMMEDIATE_OBJECT_HTML_CONTAINER %
        [ HTMLUtilities.escape_html(object.inspect) ]
    else
      object_html << make_object_html_wrapper( object )
    end
  end

  return object_html.join("\n")
end

- (Object) make_object_html_wrapper(object)

Wrap up the various parts of a complex object in an HTML fragment. If the object has already been wrapped, returns a link to the previous rendering instead.

# File 'lib/arrow/mixins.rb', line 234

def make_object_html_wrapper( object )

  # If the object has been rendered already, just return a link to the previous
  # HTML fragment
  Thread.current[ THREAD_DUMP_KEY ] ||= {}
  if Thread.current[ THREAD_DUMP_KEY ].key?( object.object_id )
    return %Q{<a href="#object-%d" class="cache-link" title="jump to previous details">%s</a>} % [
      object.object_id,
      %{&rarr; %s #%d} % [ object.class.name, object.object_id ]
    ]
  else
    Thread.current[ THREAD_DUMP_KEY ][ object.object_id ] = true
  end

  # Assemble the innards as an array of parts
  parts = [
    %{<div class="object-header">},
    %{<span class="object-class">#{object.class.name}</span>},
    %{<span class="object-id">##{object.object_id}</span>},
    %{</div>},
    %{<div class="object-body">},
  ]

  object.instance_variables.sort.each do |ivar|
    value = object.instance_variable_get( ivar )
    html = make_html_for_object( value )
    classes = %w[instance-variable]
    if value.instance_variables.empty? && !value.respond_to?( :values_at )
      classes << 'simple'
    else
      classes << 'complex'
    end
    parts << IVAR_HTML_FRAGMENT % [ classes.join(' '), ivar, html ]
  end

  parts << %{</div>}

  # Make HTML class names out of the object's namespaces
  namespaces = object.class.name.downcase.split(/::/)
  classes = []
  namespaces.each_index do |i|
    classes << namespaces[0..i].join('-') + '-object'
  end

  # Glue the whole thing together and return it
  return OBJECT_HTML_CONTAINER % [
    object.object_id,
    classes.join(" "),
    parts.join("\n")
  ]
end