MODS Display is a gem to centralize the display logic of MODS medadata.
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A gem for displaying MODS Metadata in a configurable way.


You can experiment with the output of the latest release of the gem in the demo app.


Add this line to your application's Gemfile:

gem 'mods_display'

And then execute:

$ bundle

Or install it yourself as:

$ gem install mods_display

Include the ModelExtension into your model.

class MyClass
  include ModsDisplay::ModelExtension

Configure the source of the MODS XML in your model. You can pass a string of XML to the mods_xml_source method, however it will also accept a block where you can call methods on self (so if the MODS XML string is held in MyClass#mods):

class MyClass

  mods_xml_source do |model|


Include the ControllerExtension into your rails controller (or another class if not using rails).

class MyController
  include ModsDisplay::ControllerExtension

Optionally configure the mods display gem (more on configuration later).

class MyController
  configure_mods_display do


In the class that you include the ModsDisplay::ControllerExtension you can configure various behavior for different fields. The configuration options provided by ModsDisplay::Configuration::Base are:

  • label_class
  • value_class
  • ignore!
  • delimiter
  • link

Label and Value classes

Both label_ and value_class accept strings to put in as a class.

class MyController
  include ModsDisplay::ControllerExtension

  configure_mods_display do
    title do
      label_class "title-label"
      value_class "title-value"


In certain cases an application may need to explicitly remove a portion of the MODS metadata from the display (Contact being a prime example). You can accomplish this by using the ignore! option.

class MyController
  include ModsDisplay::ControllerExtension

  configure_mods_display do
    contact do


The delimiter configuration option accepts a string which will be used to delimit multiple multiple values within a single label.

configure_mods_display do
  note do
    delimiter "<br/>"

Note: Different MODS elements will have different default delimiters (mainly varying between a comma+space or a HTML line-break).


The link configuration option takes 2 parameters. The first is a key that is a method_name available in the class including ModsDisplay::ControllerExtension and the 2nd is options to pass to that method. This method must return a string that will be used as the href attribute of the link. (NOTE: If you have the %value% token in your options that will be replaced with the value of the field being linked)

class MyController
  include ModsDisplay::ControllerExtension

  configure_mods_display do
    format do
      link :format_path, '"%value%"'

  def format_path(format)

Special Subject Configuration

Depending on the implementation of subjects there may be different ways you would want to link them. The standard way of linking will just create a link passing the value to the href and the link text. However; in certain cases the subjects should be linked so that each subject to the right of a delimiter should have the values of all its preceding values in the href.

Country > [State]("Country State") > [City]("Country State City")

This can be accomplished by setting the hierarchical_link configuration option to true for subjects

configure_mods_display do
  subject do
    hierarchical_link true

NOTE: The default delimiter is set to > for subjects.

Special Access Condition Configuration

The access condition statement is set to be ignored by default (same as ignore! configuration option). If you would like the access condition statement to display you have to pass the access condition specific display! configuration option.

configure_mods_display do
  access_condition do


Once installed, the class that included the ControllerExtension (MyController) will have the render_mods_display method available. This method takes one argument which is an instance of the class that included the ModelExtension (MyClass).

render_mods_display(@model) # where @model.is_a?(MyClass)

The basic render call will return the top-level ModsDisplay::HTML class object. Any String method (e.g. #html_safe) you call on this top-level object will be sent down to the #to_html method which will return the HTML for all the metadata in the MODS document.


You can abstract the main (first) title by calling #title on the top-level HTML method


When getting JUST the main (first) title out of the metadata, it will be useful to get the rest of the metadata without the main title. You can accomplish this by calling #body on the top-level HTML object.


Advanced Usage

You can also access the array of ModsDisplay::Values objects for a given class directly by calling the name of the class. The class names are not always intuitive for public consumption so you may want to check the code the particular method to call.

=> [#<ModsDisplay::Values @label="Abstract:", @values=["Hey. I'm an abstract."]>]

Given that this semantics that we're concerned with here are more about titles and data construction rather than XML it may be required that you find something by the label. A common example of this is the imprint class. The imprint class can return other publication data that is not the imprint statement. You'll want to select (using your favorite enumerable method) the element in the array that is an imprint.

imprint = render_mods_display(@model).imprint.find do |data|
  data.label == "Imprint:"

Release/Upgrade Notes


There are three major changes in this version.

  1. RelatedItem nodes with a type of constituent or host are now treated separately and will render the full MODS display of any nested metadata. If accessing the ModsDisplay::Values directly through their accessors (e.g. custom grouping), this new metadata is available under .nested_related_items.
    • Note: You may want to style and add some javascript toggling behavior (see exhibits for an example).
  2. Name nodes are now grouped/labeled by their role. If you were iterating over the names and splitting them out by their labels, that will need to change.
  3. Table of contents/Summaries are now split on -- and rendered as an unordered list.
    • Note: You may want to style this list.


Labels now have internationalization support. We have added colons to the english labels due to certain languages' punctuation rules requiring different spacing between the label and colon.

Given that fact, you will want to update any pre 0.3.0 code that searches for elements by label in a way that would fail with the presence of a colon.


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request