feat: URL 正規化（#208） (#226)

#208

Co-authored-by: miteruzo <miteruzo@naver.com>
Reviewed-on: #226

backend/app/models/post.rb

@@ -17,7 +17,12 @@ class Post < ApplicationRecord
            foreign_key: :target_post_id
   has_one_attached :thumbnail
 
+  before_validation :normalise_url
+
+  validates :url, presence: true, uniqueness: true
+
   validate :validate_original_created_range
+  validate :url_must_be_http_url
 
   def as_json options = { }
     super(options).merge({ thumbnail: thumbnail.attached? ?
@@ -69,4 +74,33 @@ class Post < ApplicationRecord
       errors.add :original_created_before, 'オリジナルの作成日時の順番がをかしぃです．'
     end
   end
+
+  def url_must_be_http_url
+    begin
+      u = URI.parse(url)
+    rescue URI::InvalidURIError
+      errors.add(:url, 'URL が不正です．')
+      return
+    end
+
+    if !(u in URI::HTTP) || u.host.blank?
+      errors.add(:url, 'URL が不正です．')
+      return
+    end
+  end
+
+  def normalise_url
+    return if url.blank?
+
+    self.url = url.strip
+
+    u = URI.parse(url)
+    return unless u in URI::HTTP
+
+    u.host = u.host.downcase if u.host
+    u.path = u.path.sub(/\/\Z/, '') if u.path.present?
+    self.url = u.to_s
+  rescue URI::InvalidURIError
+    ;
+  end
 end