Best way to DRY up code using procs and blocks and/or dynamic methods - ruby

Question

I am writing a way to parse websites, each "scraper" has it's own way gather information, but there is plenty of common functionality between two methods.
Differences:
One scraper uses Nokogiri to open the page via css selectors
the other scraper uses an RSS feed to gather information
Similarities:
each scraper creates an "Event" object that has the following attributes:
title
date
description
if for the Nokogiri scraper, we do something like this:
event_selector = page.css(".div-class")
event_selector.each_with_index do |event, index|
date = Date.parse(event.text) #code I want to share
end
for the RSS scraper, we do something like this
open(url) do |rss|
feed = RSS::Parser.parse(rss)
feed.items.each do |event|
description = Sanitize.fragment(event.description)
date = description[/\d{2}-\d{2}-20\d{2}/]
date = Date.strptime(date, '%m-%d-%Y') #code I want to share
end
end
^^ The date is grabbed via a regex from the description and then converted into a Date object via the .strptime method
as you can see each scraper uses 2 different method calls/ways to find the date. How could I abstract this information into a class?
I was thinking of something like this:
class scrape
attr_accessor :scrape_url, :title, :description, :date, :url
def initialize(options = {})
end
def find_date(&block)
# Process the block??
end
end
and then in each of the scraper methods do something like
scrape = Scrape.new
date_proc = Proc.new {Date.parse(event.text)}
scrape.find_date(date_proc)
Is this the right way to go about this problem? In short I want to have common functionality of two website parsers to pass the desired code into a instance method of a "scrape" class. I would greatly appreciate any tips to tackle this scenario.
Edit: Maybe it would make more sense if I say that I want to find the "date" of an event, but the way I find it - the behavior - or the specific code that is run, is different.

Answer 1

You could use an Event builder. Something like this:
class Event::Builder
def date(raw)
#date = Date.strptime(raw, '%m-%d-%Y')
end
# ... more setters (title, description) ...
def build
Event.new(date: #date, ... more arguments ..)
end
end
And then, inside the scraper:
open(url) do |rss|
builder = Event::Builder.new
feed = RSS::Parser.parse(rss)
feed.items.each do |event|
description = Sanitize.fragment(event.description)
date = description[/\d{2}-\d{2}-20\d{2}/]
builder.date(date)
# ... set other attributes ...
event = builder.build
# do something with the event ...
end
end

Answer 2

You should look into the Strategy or Template patterns. These are ways of writing code that does different things depending on some state or configuration. Essentially you'd write a Scraper class and then sub class it as WebScraper and RssScraper. Each class would inherit from the Scraper class all the common functionality but only differ in their implementation of how to get the date, description, etc.