Improved scaffolding

Author: rab

README.md

@@ -4,6 +4,8 @@ Solutions for the 2016 edition of the Advent of Code - http://adventofcode.com/2
 
 Back again for another year, the little [Advent of Code] site that has a new pair of problems to solve each new day (i.e., midnight Eastern time) and this repository holds my solutions using [ruby](http://ruby-lang.org)
 
+There are a few files that help with the mechanics of the challenge itself. The value for the `session` cookie from teh site is stored in the `./.session` file. The `day_prep.rb` retrieves the challenge description and builds the initial solution file using the `day_template.rb`. The input for the day's challenge is retrieved (and cached!) using code from the module defined in `input.rb`.
+
 My solutions for the original 2015 installment of the Advent of Code is in the repo: [rab/adventofcode2015](https://github.com/rab/adventofcode2015)
 
 My Personal [Leaderboard] stats:

day_prep.rb

@@ -0,0 +1,41 @@
+# To simplify starting a new day on the Advent of Code challenge.
+#
+# Usage: ruby day_prep.rb [day]
+#
+# Prerequisite: the presence of the ./.session file containing the "session=19827364918273..."
+#   value for the cookie.
+#
+# When: Runs anytime during the day (Eastern time) to get the challenge from the current day or
+#   from a single past date by supplying the day number as an argument.
+#
+# The "Part Two" will typically have to be retrieved manually.
+#
+require 'date'
+require 'uri'
+require 'net/http'
+require 'nokogiri'
+
+day = ARGV[0].to_i.nonzero? || Date.today.day
+year = Date.today.year
+filename = 'day%02d.rb'%[day]
+unless File.exist? filename
+  if File.exist?(html = filename.sub(/\.rb\z/,'.html'))
+    doc = Nokogiri::HTML File.read(html)
+  else
+    uri = URI('http://adventofcode.com/%d/day/%d'%[year, day])
+    req = Net::HTTP::Get.new(uri)
+    req['Cookie'] = File.read('./.session') if File.exist?('./.session')
+    res = Net::HTTP.start(uri.hostname, uri.port) {|http|
+      http.request(req)
+    }
+    doc = Nokogiri::HTML res.body.tap {|contents| File.write(html, contents) }
+  end
+
+  File.open(filename, 'w') do |f|
+    doc.css('article.day-desc').children.each do |node|
+      f.puts node.text.gsub(/^/,'# ')
+    end
+    f.puts
+    f.write File.read('day_template.rb')
+  end
+end

input.rb

@@ -1,3 +1,12 @@
+# To simplify starting a new day on the Advent of Code challenge.
+#
+# Prerequisite: the presence of the ./.session file containing the "session=19827364918273..."
+#   value for the cookie.
+#
+# Returns the cached input or retrieves and caches the indicated day's input.
+#
+# Note that some days may not have an input file if the input was specified in the description.
+
 require 'uri'
 require 'net/http'