Metadocs: Content Extraction Tools for Google Docs

Metadocs is a set of tools for extracting data out of Google Documents. It is designed to to make life easier when using Google Docs as a content source for CMSs and related applications. It provides three main features:

• A high level, idiomatic abstraction of Google Docs API entities
• BBDocs, a markup language that can be used inside Google Documents
• Metadocs Tables, a specification for storing structured data inside Google Documents

Installation

Add this line to your application's Gemfile:

gem 'metadocs'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install metadocs

Usage

Metadocs pulls data from the Google Docs API, so in order to use it you need a Credentials object that is authorized to access the document you're interacting with. Some examples are available at API Authentication.

The simplest way to use the library is by calling Metadocs::Parser.parse:

metadoc = Metadocs::Parser.parse(google_credentials, doc_id)

doc_id can be either the the URL to a Google Document or the ID section in the link.

Reading content from a document

The object returned by .parse can be iterated as a tree structure with objects that wrap Google Docs entities. There are helper methods you can call such as .bold? and .italic? for text paragraphs.

Note that some entities are currently unsupported by the Docs API, and thus will not be available in Metadocs. See more at Elements.

metadoc.each do |element|
  if element.paragraph? && element.first.bold?
    puts element.render(:html) # <div><b>This is bold,</b> this isn't!</div>
  end
end

BBDocs

BBDocs lets you annotate documents with a syntax reminiscent of BBCode. For more information, check out the BBDocs documentation.

BBDocs tag elements also appear in the parse tree:

metadoc = Metadocs::Parser.parse(
  google_credentials,
  doc_id,
  tags: [{ name: 'my-tag', attributes: ['a', 'b'] }]
)

metadoc.each do |element|
  if element.tag?
    puts [element.name, element.attributes]
    # => 'my-tag'
    # => { a: 'example', b, ... }

    element.each do |child_element|
      # Handle content nested inside the tag
    end
  end
end

Metadocs Tables

Inline tables conforming to the Metadocs Tables specification will show up as structured data in the parse result. They're useful for storing metadata inside documents. Learn more about them in the Metadocs Tables documentation.

metadoc = Metadocs::Parser.parse(
  google_credentials,
  doc_id,
  metadata_table_spec: [
    {
      name: 'my-doc-metadata',
      type: :key_value,
      keys: [
        { name: 'key-1' },
        { name: 'key-2' }
      ]
    }
  ]
)

# A doc may have multiple Metadocs Tables with the same name, so they're stored
# as an array.
metadoc['my-doc-metadata'][0]['key-1'] # => [Elements::Paragraph, ...]

Rendering

Every element in the tree can render itself to text and HTML, and it's easy to add custom renderers to the parser:

class CustomHtmlRenderer < Metadocs::HtmlRenderer
  def render_tag
    if element.name == 'blink'
      '<blink>' + render_children + '</blink>' # Why would somebody use this?
    else
      super
    end
  end
end

metadoc = Metadocs::Parser.parse(
  google_credentials,
  doc_id,
  tags: [ { name: 'blink' } ],
  renderers: { custom_html: CustomHtmlRenderer }
)

metadoc.each do |element|
  if element.tag?
    puts element.render(:text)        # => '[blink]This is blinking text![/blink]'
    puts element.render(:html)        # => '<div data-tag="blink">This is blinking text!</div>'
    puts element.render(:custom_html) # => '<blink>This is blinking text!</blink>'
  end
end

There is more information about custom renderers in the Renderers documentation.

Development

You can learn more about how Metadocs works internally in the Internals documentation.

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub.