Expand shortened urls, fails on https

Stub expand url call in test

Author: bf4

app/presenters/tweet/html_presenter.rb

@@ -14,8 +14,16 @@ def text
     buffer << tweet.tweet_text
 
     # make links anchors
-    buffer.gsub! /(https?[^\s]+)/o,
-                      %q(<a href="\\1" target="_blank">\\1</a>)
+    buffer = buffer.gsub(/(https?[^\s]+)/o) do |url|
+      require Rails.root.join('lib/expand_url')
+      begin
+        expanded_url = ExpandUrl.expand_url(url)
+      rescue ExpandUrl::ExpansionError => e
+        STDERR.puts "#{e.class}: failed expanding #{url.inspect}"
+        expanded_url = url
+      end
+      %Q(<a href="#{expanded_url}" target="_blank">#{url}</a>)
+    end
     # link hashtags
     buffer.gsub! /#(\w+)/, '<a href="http://twitter.com/search?q=%23\\1">#\\1</a>'
     # link users

lib/expand_url.rb

@@ -0,0 +1,57 @@
+require 'net/http'
+require 'uri'
+
+# e.g.
+# url = http://t.co/z4t0E1vArh
+# ExpandUrl.expand_url(url)
+# => "http://www.haaretz.com/news/national/israel-s-ag-impels-ministers-to-crack-down-on-exclusion-of-women.premium-1.519917"
+module ExpandUrl
+  class ExpansionError < StandardError; end
+  module ExpansionErrors
+    class BadUrl < ExpansionError; end
+    class BadResponse < ExpansionError; end
+  end
+  HTTP_ERRORS = [Timeout::Error, Errno::EINVAL, Errno::ECONNRESET,
+       Net::HTTPBadResponse, Net::HTTPHeaderSyntaxError, Net::ProtocolError]
+  class BasicResponse < Struct.new(:url, :code); end
+  extend self
+
+  # raises ExpandUrl::ExpansionError
+  def expand_url(url)
+    response = get_response(url)
+    case response.code
+    when '301'
+      log "url: #{url}\tresponse: #{response.inspect}"
+      expand_url(response['location'])
+    when '200'
+      log "url: #{url}\tresponse: #{response.inspect}"
+      url
+    else
+      log "url: #{url}\tresponse: #{response.inspect}"
+      expand_url(response['location'])
+    end
+  end
+
+  def get_response(url)
+    uri = url_to_uri(url)
+    Net::HTTP.get_response(uri)
+  rescue EOFError => e
+    BasicResponse.new(url, '200')
+  rescue *HTTP_ERRORS => e
+    log url.inspect + e.inspect
+    raise ExpansionErrors::BadResponse.new(e)
+  end
+
+  def url_to_uri(url)
+    begin
+      uri = URI.parse(url)
+    rescue URI::InvalidURIError, SocketError => e
+      raise ExpansionErrors::BadUrl.new(e)
+    end
+  end
+
+  def log(msg)
+    STDOUT.puts "#{msg}\t#{caller[1]}" if (ENV['debug'] == 'true')
+  end
+
+end

spec/lib/expand_url_spec.rb

@@ -0,0 +1,7 @@
+require 'spec_helper'
+
+describe ExpandUrl do
+
+  it 'should be tested'
+
+end

spec/presenters/tweet/html_presenter_spec.rb

@@ -4,13 +4,19 @@
   subject { presenter }
 
   let(:presenter) { described_class.new tweet }
+  let(:tweet_link) {
+    link = 'http://t.co/cyL9StoS'
+    ExpandUrl.stub(:expand_url).with(link).and_return(link)
+    link
+  }
   let(:tweet) {
-    Tweet.new tweet_id: "263515718753079296",
-      tweet_text: "at @SteelCityRuby with @coreyhaines - one of my favorite #rubyfriends http://t.co/cyL9StoS",
+    Tweet.new(tweet_id: "263515718753079296",
+      tweet_text: "at @SteelCityRuby with @coreyhaines - one of my favorite #rubyfriends #{tweet_link}",
       username: "joshsusser",
       media_url: "http://p.twimg.com/A6gyJmlCUAA9Il2.jpg",
       image: "A6gyJmlCUAA9Il2.jpg",
       media_display_url: "pic.twitter.com/cyL9StoS"
+      )
   }
 
   its(:username) { should == "@joshsusser" }