Merge remote-tracking branch 'pr/237' into develop

Twitter Feature on Main-View from @loadtocode

Twitter feature within home/index of LEAP web app as feed of tweets of one user's twitter account

How to use it: set up an Application-only authentication by twitter (https://dev.twitter.com/oauth/application-only) and then create a config/secrets.yml including:
```
development:
  twitter:
    enabled: false # set to true for usage
    twitter_handle: XXXXX #put your twitter handle here
    bearer_token: XXXXX #put your bearer token here
test:
  twitter:
    enabled: false # set to true for usage
    twitter_handle: XXXXX #put your twitter handle here
    bearer_token: XXXXX #put your bearer token here
```

things in the PR:

- [x] gemfile:twitter
- [x] twitter helper (caching (to avoid reaching twitter rate limits)
- [x] index twitter view
- [x] twitter css (twitter design as discussed in call: Profil-Header: Picture, Link to twitter + twitter_handle; removed picture and twitter_handle from individual tweet, heading aligns at the top, only the last 3 tweets are shown)
- [x] script to generate bearer token
- [x] script to invalidate generated bearer token
- [x] documentation (Readme + Doc)

6 files changed, 164 insertions, 12 deletions

diff --git a/app/assets/images/Twitter_Logo_Blue.png b/app/assets/images/Twitter_Logo_Blue.png
new file mode 100644
index 0000000..b5eebc8
--- /dev/null
+++ b/app/assets/images/Twitter_Logo_Blue.png
diff --git a/app/assets/stylesheets/application.scss b/app/assets/stylesheets/application.scss
index 856a559..f42044b 100644
--- a/app/assets/stylesheets/application.scss
+++ b/app/assets/stylesheets/application.scss
@@ -16,6 +16,7 @@
 // LEAP web app specific overrides
 //
 @import "leap";
+@import "twitter";
 
 // And finally bootswatch style itself
 // @import "bootswatch/cerulean/bootswatch";
diff --git a/app/assets/stylesheets/twitter.scss b/app/assets/stylesheets/twitter.scss
new file mode 100644
index 0000000..b2233d0
--- /dev/null
+++ b/app/assets/stylesheets/twitter.scss
@@ -0,0 +1,72 @@
+.twitter {
+  position: relative;
+}
+
+.twitter_header {
+  font-size: 16px;
+  text-align: left;
+  margin-bottom: 55px;
+  padding: 10px 8px;
+}
+
+.twitter_id {
+  position: absolute;
+}
+
+.twitter_image_frame {
+  display: block;
+  width: 40px;
+  height: 40px;
+  overflow: hidden;
+  position: absolute;
+  left: 0;
+  top: 0;
+  }
+
+.twitter_image_frame > img {
+  display: block;
+  position: absolute;
+  top: 0;
+  bottom: 0;
+  left: 30;
+  width: 100%;
+  margin: auto;
+  }
+
+.twitter_name {
+  padding-left: 55px;
+  line-height: 20px;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  font-size: 16px;
+}
+
+// Body = displays tweets
+.twitter_list {
+  box-sizing: border-box;
+}
+
+.tweet {
+  border-top-style: solid;
+  border-color: lightgrey;
+  padding: 10px 8px;
+}
+
+.tweet_text {
+box-sizing: border-box;
+}
+
+.tweet_text_date {
+  text-align: right;
+  padding-top: 4px;
+  font-size: 12px ;
+}
+
+.twitter_footer {
+  border-top-style: solid;
+  border-color: lightgrey;
+  padding: 10px 8px;
+  font-style: italic;
+  font-size: 12px;
+}
diff --git a/app/helpers/twitter_helper.rb b/app/helpers/twitter_helper.rb
new file mode 100644
index 0000000..f824a03
--- /dev/null
+++ b/app/helpers/twitter_helper.rb
@@ -0,0 +1,46 @@
+module TwitterHelper
+  def twitter_enabled
+    if Rails.application.secrets.twitter
+      Rails.application.secrets.twitter['enabled'] == true
+    end
+  end
+
+  def twitter_client
+    Twitter::REST::Client.new do |config|
+      config.bearer_token = Rails.application.secrets.twitter['bearer_token']
+    end
+  end
+
+  def twitter_handle
+    Rails.application.secrets.twitter['twitter_handle']
+  end
+
+  def twitter_user_info
+      $twitter_user_info ||= []
+  end
+
+  def update_twitter_info
+    twitter_user_info[0] = Time.now
+    twitter_user_info[1] = twitter_client.user(twitter_handle).name
+    twitter_user_info[2] = twitter_client.user_timeline(twitter_handle).select{ |tweet| tweet.text.start_with?('RT','@')==false}.take(3)
+  end
+
+  def cached_info
+    if twitter_user_info[0] == nil
+      update_twitter_info
+    else
+      if Time.now > twitter_user_info[0] + 15.minutes
+        update_twitter_info
+      end
+    end
+    twitter_user_info
+  end
+
+  def twitter_name
+    cached_info[1]
+  end
+
+  def tweets
+    cached_info[2]
+  end
+end
diff --git a/app/views/home/_content.html.haml b/app/views/home/_content.html.haml
index 67e4533..5341189 100644
--- a/app/views/home/_content.html.haml
+++ b/app/views/home/_content.html.haml
@@ -1,12 +1,19 @@
-.row
-  %h1= t(:welcome, :provider => APP_CONFIG[:domain])
-  .p=t(:welcome_message_html)
-
-.row
-  = home_page_buttons
-
-  - if Rails.env == 'development'
-    .row
-      %hr
-      %p
-        = link_to "make donation", new_payment_path if APP_CONFIG[:payment].present?
+.col-md-8
+  .row
+    %h1= t(:welcome, :provider => APP_CONFIG[:domain])
+    .p=t(:welcome_message_html)
+
+  .row
+    = home_page_buttons
+
+.col-md-1
+
+.col-md-3
+  .row
+    = render 'twitter/index'
+
+    - if Rails.env == 'development'
+      .row
+        %hr
+        %p
+          = link_to "make donation", new_payment_path if APP_CONFIG[:payment].present?
diff --git a/app/views/twitter/_index.html.erb b/app/views/twitter/_index.html.erb
new file mode 100644
index 0000000..a7ebd1b
--- /dev/null
+++ b/app/views/twitter/_index.html.erb
@@ -0,0 +1,26 @@
+<% if twitter_enabled == true %>
+  <div class="twitter">
+
+      <div class="twitter_header">
+        <div class="twitter_id">
+          <div class="twitter_image_frame"><%= image_tag("Twitter_Logo_Blue.png") %></div>
+          <div class="twitter_name"><%= twitter_name%><br><a href="https://twitter.com/loadtocode">@<%= twitter_handle %></a></div>
+        </div>
+      </div>
+
+      <div class="twitter_list">
+        <% tweets.each do |e| %>
+          <div class="tweet">
+            <div class="tweet_text"><%= " #{e.text}" %>
+            </div>
+            <div class="tweet_text_date">tweeted on <% t = e.created_at%> <%= t.strftime("%m/%d/%y").to_s %>
+            </div>
+          </div>
+        <% end %>
+    </div>
+
+    <div class="twitter_footer">
+      <p>This feed uses a Ruby interface to access the Twitter API. Within LEAP Twitter does not track you.</p>
+    </div>
+</div>
+<% end %>