SlideShare Liquid tag (#1485)

* Create slideshare_tag.rb

* Create slideshare_tag_spec.rb

* Add slide share

* rubocop compliance

* Still learning

https://ruby-doc.org/core-2.5.1/Regexp.html

* More secure match

Co-Authored-By: Link2Twenty <AndrewB05@gmail.com>

* Strip whitespace

Co-Authored-By: Link2Twenty <AndrewB05@gmail.com>

* Strip before regex

Co-Authored-By: Link2Twenty <AndrewB05@gmail.com>

* Remove latter strip

Co-Authored-By: Link2Twenty <AndrewB05@gmail.com>

app/liquid_tags/slideshare_tag.rb

@@ -0,0 +1,33 @@
+class SlideshareTag < LiquidTagBase
+  def initialize(tag_name, key, tokens)
+    super
+    @key    = validate key.strip
+    @height = 450
+  end
+
+  def render(_context)
+    finalize_html <<-HTML
+      <iframe
+        src="//www.slideshare.net/slideshow/embed_code/key/#{@key}"
+        alt="#{@key} on slideshare.net"
+        width="100%"
+        height="#{@height}"
+        frameborder="0"
+        scrolling="no"
+        allowfullscreen>
+      </iframe>
+    HTML
+  end
+
+  private
+
+  def validate(key)
+    if key.match?(/\A[a-zA-Z0-9]{14}\Z/)
+      key
+    else
+      raise StandardError, "Invalid Slideshare Key"
+    end
+  end
+end
+
+Liquid::Template.register_tag("slideshare", SlideshareTag)

app/views/pages/_editor_guide_text.html.erb

@@ -121,6 +121,10 @@
       <li><strong>YouTube:</strong> <code>{% youtube dQw4w9WgXcQ %}</code></li>
       <li><strong>Vimeo:</strong> <code>{% vimeo 193110695 %}</code></li>
     </ul>
+      
+    <h3><strong>SlideShare Embed</strong></h3>
+    <p>All you need is the SlideShare <code>key</code></p>
+    <code>{% slideshare rdOzN9kr1yK5eE %}</code>
 
     <h3><strong>CodePen Embed</strong></h3>
     <p>All you need is the full CodePen <code>link</code>, ending in the pen ID code, as follows:</p>

spec/liquid_tags/slideshare_tag_spec.rb

@@ -0,0 +1,16 @@
+require "rails_helper"
+
+RSpec.describe SlideshareTag, type: :liquid_template do
+  describe "#key" do
+    let(:valid_key) { "rdOzN9kr1yK5eE" }
+
+    def generate_tag(key)
+      Liquid::Template.register_tag("slideshare", SlideshareTag)
+      Liquid::Template.parse("{% slideshare #{key} %}")
+    end
+
+    it "accepts a valid key" do
+      expect { generate_tag(valid_key) }.not_to raise_error
+    end
+  end
+end