Add tags filter to blog posts

Rules

@@ -24,6 +24,8 @@ preprocess do
   update_blog_attributes
   create_yearly_items('Blog')
   create_yearly_items('Events')
+  create_tagly_items('Blog')
+  create_tagly_items('Events')
   convert_event_time_to_timestamps
 
   all_events.each do |event|

content/blog/19-20/corona.md

@@ -3,6 +3,8 @@ title: "Zeus en Corona"
 created_at: 11-03-2020
 description: Corona en de invloed ervan op Zeus WPI
 author: Robbe Van Herck
+tags:
+    - Corona
 ---
 Beste Zeussers en Zeusinnen,
 

content/blog/19-20/vleor.md

@@ -4,6 +4,8 @@ title: "Het vervolg op het avontuur van de Vleor"
 created_at: 07-07-2020
 description: Eindelijk, de Zeuskelder heeft weer een nieuwe vloer!
 toc: true
+tags:
+  - vloer
 ---
 
 **vleor** (_de; m;_ meervoud: _vleoren_)

content/blog/20-21/bestuur20_21.md

@@ -3,6 +3,8 @@ title: "Zeusbestuur 2020-2021"
 created_at: 6-7-2020
 description: "Het gloriZeuse nieuw bestuur"
 author: "Robbe Van Herck"
+tags:
+    - Bestuur
 ---
 
 > Hallo mijn naam is Jasper en ik zou nog steeds sysadmin willen blijven
@@ -25,4 +27,3 @@ Voor iedereen die niet op de verkiezingen was of de uitslag vergeten is, hier ee
 | Evenementen    | Ruben De Facq          |
 
 Veel succes en veel plezier van jullie oud bestuur. Het gaat gegarandeerd onvergetelijk worden! 🧡
-

content/blog/20-21/wij-coden-voort.md

@@ -3,6 +3,9 @@ title: "Wij coden voort"
 created_at: 21-7-2020
 description: "We mogen de kelder opnieuw openen"
 author: "Jasper Devreker"
+tags:
+  - Corona
+  - General update
 ---
 
 We hebben via het WVK[^wvk] doorgekregen dat we onze geliefde kelder terug mogen openen.

layouts/blogs.erb

@@ -19,24 +19,41 @@
         <% end %>
         <% end %>
       </ul>
+      <p class="menu-label">
+        Tag
+      </p>
+      <ul class="menu-list">
+        <% tag_blog_items.each do |tag, item| %>
+        <% if @item_rep && @item_rep.path == item.path %>
+        <li>
+          <a href="#" class="is-active">
+            <%= tag %>
+          </a>
+        </li>
+        <% else %>
+        <li>
+          <%= link_to tag, item %>
+        </li>
+        <% end %>
+        <% end %>
+      </ul>
     </aside>
   </div>
   <div class="column">
     <div class="columns is-multiline">
       <div class="column">
-      <% posts_in_year(item[:academic_year]).each_with_index.select {|e, i| i.even?}.map(&:first).each do |post| %>
+      <% posts_in_year_or_with_tag(item).each_with_index.select {|e, i| i.even?}.map(&:first).each do |post| %>
         <%= render '/partials/_blog_preview.*', post: post %>
       <% end %>
       </div>
 
       <div class="column">
-      <% posts_in_year(item[:academic_year]).each_with_index.reject {|e, i| i.even?}.map(&:first).each do |post| %>
+      <% posts_in_year_or_with_tag(item).each_with_index.reject {|e, i| i.even?}.map(&:first).each do |post| %>
         <%= render '/partials/_blog_preview.*', post: post %>
       <% end %>
       </div>
-
     </div>
-    <% if posts_in_year(@item[:academic_year]).empty? %>
+    <% if posts_in_year_or_with_tag(item).empty? %>
       <div class="content has-text-centered">
         <h1>Sorry.</h1>
         <h2>No blog posts yet this year.</h2>

lib/helpers/archives.rb

@@ -3,7 +3,7 @@ module ArchiveHelper
     # Set.to_a to prevent duplicates
     Set.new(items
               .find_all('/blog/*/*')
-              .map { |i| i.identifier.to_s[/\d\d-\d\d/] })
+              .map { |i| i.identifier.to_s.split('/')[-2] })
               .to_a
        .sort
        .push(@config[:academic_year])
@@ -14,6 +14,20 @@ module ArchiveHelper
     academic_years.reverse.map { |y| [y, items["/blog/#{y}.html"]] }
   end
 
+  def tags
+    # Set.to_a to prevent duplicates
+    Set.new(items
+        .find_all('/blog/*/*')
+        .flat_map { |i| i[:tags] || [] })
+        .to_a
+      .sort
+      .uniq
+  end
+
+  def tag_blog_items
+    tags.map { |y| [y, items["/blog/#{y}.html"]]}
+  end
+
   def pretty_year(year)
     year = year.scan(/\d\d/)
     "'#{year[0]} - '#{year[1]}"
@@ -22,4 +36,18 @@ module ArchiveHelper
   def posts_in_year(y)
     items.find_all("/blog/#{y}/*").sort_by { |x| x[:created_at] }.reverse
   end
+
+  def posts_with_tag(tag)
+    items
+      .find_all('/blog/*/*')
+      .filter{|i| (i[:tags] || []).include? tag }
+  end
+
+  def posts_in_year_or_with_tag(item)
+    if item[:is_yearly]
+      posts_in_year(item[:academic_year])
+    else
+      posts_with_tag(item[:tag])
+    end
+  end
 end

lib/helpers/preprocess.rb

@@ -56,7 +56,7 @@ module PreprocessHelper
       i.update_attributes(
         # Tag all posts with article (for Blogging helper)
         kind: 'article',
-        academic_year: i.identifier.to_s[/\d\d-\d\d/],
+        academic_year: i.identifier.to_s[/\d-\d/],
         created_at: Date.parse(i[:created_at])
       )
     end
@@ -72,7 +72,7 @@ module PreprocessHelper
     years.each do |year|
       @items.create(
         '',
-        { academic_year: year, title: type },
+        { academic_year: year, title: type, is_yearly: true },
         "/#{type.downcase}/#{year}.html"
       )
     end
@@ -84,6 +84,21 @@ module PreprocessHelper
     )
   end
 
+  def create_tagly_items(type)
+    type = type.to_s
+    tags = @items.find_all("/#{type.downcase}/*/*")
+      .flat_map { |i| i[:tags] || [] }
+      .uniq
+
+    tags.each do |tag|
+      @items.create(
+        '',
+        { tag: tag, title: type, is_yearly: false },
+        "/#{type.downcase}/#{tag}.html"
+      )
+    end
+  end
+
   def convert_event_time_to_timestamps
     @items.find_all('/events/*/*.md').each do |event|
       # HACK: Strings in a format like "2017-10-05T20:45:00+0200" automatically get converted to Time