Extracts content like title, summary, and images from web pages like Dracula extracts blood: with care and finesse.
Extractula attempts to extract the core content from a web page. For a news article or blog post this would be the content of the article itself. For a github project this would be the main README file. The library also has logic for writing your own custom extractors. This is useful if you want to write extractors for popular sites that you want to build custom support for.
gem install extractula --source http://gemcutter.org
require 'extractula' some_html = "..." # get some html to extract, yo! extracted_content = Extractula.extract(url, some_html) extracted_content.title # pulled from the page extracted_content.url # what you passed in extracted_content.content # the main content body (article, blog post, etc) extracted_content.summary # an automatically generated plain text summary of the content extracted_content.image_urls # the urls for images that appear in the content extracted_content.video_embed # the embed code if a video is embedded in the content Extractula.add_extractor(SomeClass) # so you can add a custom extractor
The “Use” section showed adding a custom extractor. This should be a class that at a minimum implements the following methods.
class MyCustomExtractor def self.can_extract?(url, html) end def extract(url, html) # should return a Extractula::ExtractedContent object end end
Notice that can_extract? is a class method while extract is an instance method. Extract should return an ExtractedContent object.
The ExtractedContent object holds the results of an extraction. It additionally has methods to automatically generate a summary, image_urls, and video_embed code from the content. If you implement a custom extractor and want to provide the summary, image_urls, and video_embed, simply pass those values into the constructor for ExtractedContent. Here are some examples:
extracted_content = ExtractedContent.new(:url => "http://pauldix.net", :content => "...some content...") extracted_content.summary # auto-generated from content extracted_content.image_urls # auto-generated from content extracted_content.video_embed # auto-generated from content extracted_content = ExtractedContent.new(:url => "http://pauldix.net", :content => "...some content...", :summary => "a summary", :image_urls => ["foo.jpg"], :video_embed => "blah") extracted_content.summary # "a summary" extracted_content.image_urls # ["foo.jpg"] extracted_content.video_embed # "blah"
Zero, one, or more of the values can be passed into the ExtractedContent constructor. It will auto-generate ones not passed in and keep the others.
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