Initial release of Discourse

app/models/site_customization.rb

@@ -0,0 +1,144 @@
+class SiteCustomization < ActiveRecord::Base
+  
+  CACHE_PATH = 'stylesheet-cache'
+  @lock = Mutex.new 
+
+  before_create do 
+    self.position ||= (SiteCustomization.maximum(:position) || 0) + 1
+    self.enabled ||= false
+    self.key ||= SecureRandom.uuid
+    true
+  end
+
+  before_save do 
+    if self.stylesheet_changed?
+      begin 
+        self.stylesheet_baked = Sass.compile self.stylesheet
+      rescue Sass::SyntaxError => e
+        error = e.sass_backtrace_str("custom stylesheet")
+        error.gsub!("\n", '\A ')
+        error.gsub!("'", '\27 ')
+        
+        self.stylesheet_baked = 
+"#main {display: none;}
+footer {white-space: pre; margin-left: 100px;}
+footer:after{ content: '#{error}' }"
+      end
+    end
+  end
+
+  after_save do
+    if self.stylesheet_changed?
+      if File.exists?(self.stylesheet_fullpath)  
+        File.delete self.stylesheet_fullpath 
+      end
+    end
+    self.remove_from_cache!
+    if self.stylesheet_changed?
+      self.ensure_stylesheet_on_disk!
+      MessageBus.publish "/file-change/#{self.key}", self.stylesheet_hash
+    end
+    MessageBus.publish "/header-change/#{self.key}", self.header if self.header_changed?
+
+  end
+
+  after_destroy do 
+    if File.exists?(self.stylesheet_fullpath)  
+      File.delete self.stylesheet_fullpath 
+    end
+    self.remove_from_cache!
+  end
+
+
+  def self.custom_stylesheet(preview_style)
+    style = lookup_style(preview_style)
+    style.stylesheet_link_tag.html_safe if style
+  end
+
+  def self.custom_header(preview_style)
+    style = lookup_style(preview_style)
+    style.header.html_safe if style
+  end
+
+  def self.override_default_style(preview_style)
+    style = lookup_style(preview_style)
+    style.override_default_style if style
+  end
+
+  def self.lookup_style(key)
+
+    return if key.blank?
+    
+    # cache is cross site resiliant cause key is secure random 
+    @cache ||= {}
+    ensure_cache_listener
+    style = @cache[key]
+    return style if style
+    
+    @lock.synchronize do 
+      style = self.where(key: key).first
+      @cache[key] = style
+    end
+  end
+
+  def self.ensure_cache_listener
+    unless @subscribed
+      klass = self
+      MessageBus.subscribe("/site_customization") do |msg|
+        message = msg.data
+        klass.remove_from_cache!(message["key"], false) 
+      end
+
+      @subscribed = true
+    end
+  end
+
+  def self.remove_from_cache!(key, broadcast=true)
+    MessageBus.publish('/site_customization', {key: key}) if broadcast
+    if @cache
+      @lock.synchronize do 
+        @cache[key] = nil
+      end
+    end
+  end
+
+  def remove_from_cache!
+    self.class.remove_from_cache!(self.key)
+  end
+
+  def stylesheet_hash
+    Digest::MD5.hexdigest(self.stylesheet)
+  end
+
+  def ensure_stylesheet_on_disk!
+    path = stylesheet_fullpath
+    dir = "#{Rails.root}/public/#{CACHE_PATH}"
+    FileUtils.mkdir_p(dir)
+    unless File.exists?(path)
+      File.open(path, "w") do |f|
+        f.puts self.stylesheet_baked
+      end
+    end
+  end
+
+  def stylesheet_filename
+    file = ""
+    dir = "#{Rails.root}/public/#{CACHE_PATH}"
+    path = dir + file
+
+    "/#{CACHE_PATH}/#{self.key}.css"
+  end
+
+  def stylesheet_fullpath
+    "#{Rails.root}/public#{self.stylesheet_filename}"
+  end
+
+  def stylesheet_link_tag
+    return "" unless self.stylesheet.present?
+    return @stylesheet_link_tag if @stylesheet_link_tag
+    ensure_stylesheet_on_disk!
+    @stylesheet_link_tag = "<link class=\"custom-css\" rel=\"stylesheet\" href=\"#{self.stylesheet_filename}?#{self.stylesheet_hash}\" type=\"text/css\" media=\"screen\">"
+  end
+
+
+end