Pick the correct form from Mechanize results via CSS selector

Question

So I use Mechanize to fetch a list of forms for a page. The form identification can vary for websites, so I need something more stable, such as a selector.

Is there a way I can use a simple CSS selector to pick the right form from a list of forms provided by Mechanize?

Answer 1

Yes. The page object returned by Mechanize is a Nokogiri document so you can use all of Nokogiri's methods to find a node in the DOM.

search and at are the generic methods, and both take either CSS or XPath selectors. at is equivalent to search('some selector').first. I use those two for the vast majority of times I need to find a node. There are also css and xpath which are selector-type specific and their at equivalents of at_css and at_xpath.

Consider this code:

require 'mechanize'

agent = Mechanize.new
page = agent.get('http://www.example.net')
page.class # => Mechanize::Page
page.at('title').class # => Nokogiri::XML::Element
page.at('title').text # => "Example Domain"

This example gets the page's <title> but you can easily interpolate how to get a particular form from the DOM you're working with from this.

Answer 2

You can use the form_node method to match the form to a <form> element:

form = page.forms.find{|f| f.form_node == page.at('[name=f]')}