TableUnspanner

Takes a string containing an HTML <table> which has rowspan and/or colspan attributes on <th> and <td> elements and returns a processed version of the table with those attributes replaced by duplicate rows to make scraping them easier.

Example

If you're scraping a webpage that has the table below on it you want the row containing Bob to also contains the <td> element which is implied by the rowspan attribute on the previous row.

<table>
  <tr>
    <th>Name</th>
    <th>Role</th>
  </tr>
  <tr>
    <td>Alice</td>
    <td rowspan="2">Test subject</td>
  </tr>
  <tr>
    <td>Bob</td>
  </tr>
</table>

After running the table above though table_unspanner it would then look like this, making it much easier to scrape.

<table>
  <tr>
    <th>Name</th>
    <th>Role</th>
  </tr>
  <tr>
    <td>Alice</td>
    <td>Test subject</td>
  </tr>
  <tr>
    <td>Bob</td>
    <td>Test subject</td>
  </tr>
</table>

It also does what you'd expect for any colspan attributes that it encounters.

Installation

Add this line to your application's Gemfile:

gem 'table_unspanner'

And then execute:

$ bundle

Or install it yourself as:

$ gem install table_unspanner

Usage

To use the library create a new instance of TableUnspanner::UnspannedTable, passing a string containing an HTML <table> to the constructor. You can then call the #nokogiri_node method to retrieve the processed version of the table as a Nokogiri::Node instance. Alternatively you can call #html_string if you just want to get back a string containing the HTML for the table.

require 'table_unspanner'

table = <<-TABLE
<table>
  <tr>
    <th>Name</th>
    <th>Role</th>
  </tr>
  <tr>
    <td>Alice</td>
    <td rowspan="2">Test subject</td>
  </tr>
  <tr>
    <td>Bob</td>
  </tr>
</table>
TABLE

unspanned_table = TableUnspanner::UnspannedTable.new(table)

# Access the `Nokogiri::Node` instance for the table
unspanned_table.nokogiri_node

# Or just get the raw HTML as a string
unspanned_table.html_string

Development

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 tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/everypolitician/table_unspanner.