feat(faq): variabilize application name, host, contact_email

app/services/faqs_loader_service.rb

@@ -4,8 +4,12 @@ class FAQsLoaderService
   PATH = Rails.root.join('doc', 'faqs').freeze
   ORDER = ['usager', 'instructeur', 'administrateur'].freeze
 
-  def initialize
-    @faqs_by_path ||= Rails.cache.fetch("faqs_data", expires_in: 1.day) do
+  attr_reader :substitutions
+
+  def initialize(substitutions)
+    @substitutions = substitutions
+
+    @faqs_by_path ||= Rails.cache.fetch(["faqs_data", substitutions], expires_in: 1.day) do
       load_faqs
     end
   end
@@ -13,7 +17,7 @@ class FAQsLoaderService
   def find(path)
     file_path = @faqs_by_path.fetch(path).fetch(:file_path)
 
-    FrontMatterParser::Parser.parse_file(file_path)
+    parse_with_substitutions(file_path)
   end
 
   def faqs_for_category(category)
@@ -36,7 +40,7 @@ class FAQsLoaderService
 
   def load_faqs
     Dir.glob("#{PATH}/**/*.md").each_with_object({}) do |file_path, faqs_by_path|
-      parsed = FrontMatterParser::Parser.parse_file(file_path)
+      parsed = parse_with_substitutions(file_path)
       front_matter = parsed.front_matter.symbolize_keys
 
       faq_data = front_matter.slice(:slug, :title, :category, :subcategory, :locale, :keywords).merge(file_path: file_path)
@@ -45,4 +49,13 @@ class FAQsLoaderService
       faqs_by_path[path] = faq_data
     end
   end
+
+  # Substitute all string before front matter parser so metadata are also substituted.
+  # using standard ruby formatting, ie => `%{my_var} % { my_var: 'value' }`
+  # We have to escape % chars not used for substitutions, ie. not preceeded by {
+  def parse_with_substitutions(file_path)
+    substituted_content = File.read(file_path).gsub(/%(?!{)/, '%%') % substitutions
+
+    FrontMatterParser::Parser.new(:md).call(substituted_content)
+  end
 end