Spidy

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Installation

Add this line to your application's Gemfile:

gem 'spidy'

And then execute:

$ bundle

Or install it yourself as:

$ gem install spidy

Usage

Connectors

Spidy supports different connectors for fetching web pages:

  1. HTML Connector (Mechanize): Default connector for regular HTTP requests and HTML parsing
  2. JSON Connector: For parsing JSON APIs
  3. XML Connector: For parsing XML responses
  4. Lightpanda Connector: For JavaScript-rendered websites (uses Playwright)

Lightpanda Connector for JavaScript-Rendered Websites

The Lightpanda connector allows you to process JavaScript-rendered websites by connecting to a running lightpanda CDP server.

Prerequisites
  1. Install the Playwright Ruby client:
$ gem install playwright-ruby-client
  1. Start a lightpanda CDP server in a separate terminal:
$ lightpanda serve --host 127.0.0.1 --port 9222
Usage
# Define a scraper with lightpanda support
scraper = Spidy.define do
  # Use the :lightpanda connector for JavaScript-rendered sites
  spider(as: :lightpanda) do |yielder, connector, url|
    connector.call(url) do |page|
      # Process the JavaScript-rendered page
      # page is a Nokogiri-like object
      yielder.call(page)
    end
  end

  define(as: :html) do
    let(:title, 'title')
    # Extract content from JS-rendered page...
  end
end
Configuration

You can customize the lightpanda CDP server connection using environment variables:

# Set custom host and port
$ LIGHTPANDA_HOST=192.168.1.100 LIGHTPANDA_PORT=9333 ruby your_script.rb

Check example/playwright_example.rb for a complete example.

Command Line Usage

Create a definition file (e.g., website.rb):

Spidy.define do
  spider(as: :html) do |yielder, connector, url|
    connector.call(url) do |html|
      # html is a Nokogiri object (from Mechanize)
      yielder.call(url)
    end
  end

  define(as: :html) do
    let(:object_name, 'nokogiri query')
  end
end

Use it from the command line:

echo 'http://example.com' | spidy each website.rb > urls
cat urls | spidy call website.rb > website.json
# shorthand
echo 'http://example.com' | spidy each website.rb | spidy call website.rb | jq .

Development Console

Start an interactive console with your definition:

spidy console website.rb

Reload your source code during development:

irb(#<Spidy::Console>)> reload!

Example console usage:

each('http://example.com') { |url| break url }
call('http://example.com') { |html| break html } # html is a Nokogiri object (from Mechanize)

Ruby Code Usage

Create and use a scraper in your Ruby code:

scraper = Spidy.define do
  # Implement spiders and scrapers
  spider(as: :html) do |yielder, connector, url|
    connector.call(url) do |page|
      yielder.call(page)
    end
  end

  define(as: :html) do
    let(:title, 'title')
    let(:links) { |doc| doc.css('a').map { |a| a['href'] } }
  end
end

# Extract URLs from a site
scraper.each(url) do |page_url|
  # Process each URL found
  puts page_url
end

# Extract structured data from a site
result = scraper.call(url)
puts "Title: #{result[:title]}"
puts "Found #{result[:links].size} links"

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec 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/aileron-inc/spidy. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Crawler project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.