Simple Scraper

This is a fairly simple gem that will help you simplify the parsing of web pages.

How it works

Gem is based on several libraries that do most of the work:

• HTTParty is an HTTP client
• Parallel allows performing queries in multiple threads
• Nokogiri is an HTML, XML, SAX, and Reader parser

Installation

Add this line to your application's Gemfile:

gem 'simple-scraper'

And then execute:

$ bundle

Or install it yourself in the following way:

$ gem install simple-scraper

Usage

require 'simple/scraper'

scraper = Simple::Scraper::Parser.new(
    title: { selector: "//h1[@class='title']", handler: ->(els) { els.first.text }, default: 'Ruby' },
    summary: { selector: "//h2[@class='summary']", handler: ->(els) { els.first.text } },
    link: { selector: "//a[@class='link']", handler: ->(els) { els.first['href'] } },
    text_array: { selector: "//*[@class='link']", handler: ->(els) { els.map(&:text) } }
)

result1 = scraper.parse('https://www.codica.com/')
result2 = scraper.parse(['https://www.codica.com/1', 'https://www.codica.com/2'])

The response will be similar to:

[
  {
    "title": "scraped title text",
    "summary": "scraped summary text",
    "link": "https://www.codica.com/blog/top-ruby-gems-we-cant-live-without/",
    "text_array": ["text", "text" ...]
  },
  ...
]

Or just find a page:

Simple::Scraper::Finder.find(url: 'https://www.codica.com/', query: {}, headers: {}) do |page|
  # page is an instance of Nokogiri::HTML::Document
end

Scraper attributes

• title, summary, link, text_array - Random hash keys, they may be whatever you want.
• selector - XPath. With its help you can find desired elements on the page.
• handler - Any ruby object that can respond to #call method (proc, lambda or plain ruby class that has defined #call method). One argument will be passed to the handler which is an array of the elements found on the page. Each element is an instance of Nokogiri::XML::Element. You can read Nokogiri documentation for more info.
• default - In case scraper cannot find the desired element using selector, the value provided for the default attribute will be returned.

Query parameters and headers

query = { page: 2 }
headers = { 'Authorization': 'Bearer' }
result = scraper.parse('https://www.codica.com/', query: query, headers: headers)

Configuration

Proxy

Simple::Scraper.configure do |config|
  config.proxy_addr = 'proxy.something.com'
  config.proxy_port = 80
  config.proxy_user = 'user:'
  config.proxy_pass = 'password'
end

Logging

Simple::Scraper.configure do |config|
  config.logger = Logger.new('path/to/my/logs')
end

By default the logging is turned off

Multithreading

Simple::Scraper.configure do |config|
  config.number_of_threads = 20
end

By default scraper works in 1 thread.

Reset

You might need to reset configuration to defaults

Simple::Scraper.reset

Now you can provide new configuration if needed

License

Copyright © 2015-2019 Codica. It is released under the MIT License.

About Codica

simple-scraper is maintained and funded by Codica. The names and logos for Codica are trademarks of Codica.

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