Add Twitter.

.env.example

@@ -1,5 +1,7 @@
 REDIS_URL=redis://localhost:6379/3
 
+TWITTER_ACCESS_TOKEN=
+
 GOOGLE_API_KEY=
 
 VIMEO_ACCESS_TOKEN=

README.md

@@ -12,6 +12,18 @@ You need to get API keys for the respective services and populate the environmen
 
 A couple of services do not have official APIs, or do not require API keys, so they will work without any keys.
 
+#### Twitter
+
+Go to [Twitter Application Management](https://apps.twitter.com/) and create a new app.
+
+Once you have the consumer key and consumer secret, run the following to get the bearer token.
+
+```
+curl -X POST -d grant_type=client_credentials -u CONSUMER_KEY:CONSUMER_SECRET https://api.twitter.com/oauth2/token
+```
+
+Copy the `access_token` and put it in the config.
+
 #### Google
 
 Go to the [Google Developer Console](https://console.developers.google.com/), create a project and a server key. Copy the server key.

app.rb

@@ -45,6 +45,43 @@
   end
 end
 
+get "/twitter" do
+  return "Insufficient parameters" if params[:q].empty?
+
+  if /twitter\.com\/i\// =~ params[:q] or /twitter\.com\/who_to_follow\// =~ params[:q]
+    return "Unsupported url. Sorry."
+  elsif /twitter\.com\/hashtag\// =~ params[:q]
+    return "This app does not support hashtags. Sorry."
+  elsif /twitter\.com\/(?:#!\/)?(?<user>[^\/?#]+)/ =~ params[:q]
+    # https://twitter.com/#!/infected
+    # https://twitter.com/infected
+  else
+    # it's probably a username
+    user = params[:q]
+  end
+
+  response = TwitterParty.get("/users/lookup.json", query: { screen_name: user })
+  return "Can't find a user with that name. Sorry." if response.code == 404
+  raise TwitterError.new(response) if !response.success?
+
+  user_id = response.parsed_response[0]["id_str"]
+  screen_name = response.parsed_response[0]["screen_name"]
+  redirect "/twitter/#{user_id}/#{screen_name}"
+end
+
+get %r{/twitter/(?<id>\d+)(/(?<username>.+))?} do |id, username|
+  @user_id = id
+
+  response = TwitterParty.get("/statuses/user_timeline.json", query: { user_id: id, count: 200, include_rts: "1" })
+  raise TwitterError.new(response) if !response.success?
+
+  @data = response.parsed_response
+  @username = @data[0]["user"]["screen_name"] rescue username
+
+  content_type :atom
+  erb :twitter_feed
+end
+
 get "/youtube" do
   return "Insufficient parameters" if params[:q].empty?
 

app/twitter_party.rb

@@ -0,0 +1,15 @@
+# https://dev.twitter.com/rest/reference/get/statuses/user_timeline
+
+class TwitterParty
+  include HTTParty
+  base_uri "https://api.twitter.com/1.1"
+  headers Authorization: "Bearer #{ENV["TWITTER_ACCESS_TOKEN"]}"
+  format :json
+end
+
+class TwitterError < PartyError; end
+
+error TwitterError do |e|
+  status 503
+  "There was a problem talking to Twitter."
+end

views/index.erb

@@ -28,6 +28,16 @@
   </header>
 
   <div class="container">
+<% if ENV["TWITTER_ACCESS_TOKEN"] %>
+    <form class="input-group" method="get" action="twitter">
+      <div class="input-group-addon"><label for="twitter_q">Twitter</label></div>
+      <input class="form-control" type="search" name="q" id="twitter_q" placeholder="Enter a Twitter handle or a url." required>
+      <span class="input-group-btn">
+        <input class="btn btn-primary" type="submit" value="Get RSS Feed">
+      </span>
+    </form>
+<% end %>
+
 <% if ENV["GOOGLE_API_KEY"] %>
     <form class="input-group" method="get" action="youtube">
       <div class="input-group-addon"><label for="youtube_q">YouTube</label></div>

views/twitter_feed.erb

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<feed xmlns="http://www.w3.org/2005/Atom">
+  <id>twitter:<%= @user_id %></id>
+  <title><%= @username %> on Twitter</title>
+  <icon>https://abs.twimg.com/favicons/favicon.ico</icon>
+  <link href="<%= request.original_url.esc %>" rel="self" />
+  <link href="https://twitter.com/<%= @username %>" rel="alternate" />
+  <updated><%= Time.parse(@data[0]["created_at"]) if @data[0] %></updated>
+<%- @data.each do |tweet| -%>
+
+  <entry>
+    <id>twitter:tweet:<%= tweet["id_str"] %><%= ":#{params[:cachebuster]}" if params[:cachebuster] %></id>
+    <title><%= tweet["text"].to_line.esc %></title>
+    <link href="https://twitter.com/<%= @username %>/status/<%= tweet["id_str"] %>" />
+    <updated><%= Time.parse(tweet["created_at"]) %></updated>
+    <author><name><%= @username %></name></author>
+    <content type="html">
+<%= tweet["text"].esc %>
+    </content>
+  </entry>
+<%- end -%>
+</feed>