迁移附件所有Markdown图片的的url

db/migrate/20190713022300_modify_md_attachment_url_for_md_cotents.rb

@@ -0,0 +1,30 @@
+class ModifyMdAttachmentUrlForMdCotents < ActiveRecord::Migration[5.2]
+  def change
+    # 更新MarkDown图片的URL
+    homework_commons = HomeworkCommon.all
+    homework_commons.find_each do |hc|
+      hc.update_column(:description, hc.description.gsub("![](/attachments/download", "![](/api/attachments")) if hc.description.present?
+    end
+
+    challenges = Challenge.all.unscoped
+    challenges.find_each do |c|
+      c.update_column(:task_pass, c.task_pass.gsub("![](/attachments/download", "![](/api/attachments")) if c.task_pass.present?
+    end
+
+    challenge_answers = ChallengeAnswer.all.unscoped
+    challenge_answers.find_each do |ca|
+      ca.update_column(:contents, ca.contents.gsub("![](/attachments/download", "![](/api/attachments")) if ca.contents.present?
+    end
+
+    shixun_infos = ShixunInfo.all
+    shixun_infos.find_each do |si|
+      si.update_column(:propaedeutics, si.propaedeutics.gsub("![](/attachments/download", "![](/api/attachments")) if si.propaedeutics.present?
+      si.update_column(:description, si.description.gsub("![](/attachments/download", "![](/api/attachments")) if si.description.present?
+    end
+
+    subjects = Subject.all
+    subjects.find_each do |s|
+      s.update_column(:description, s.description.gsub("![](/attachments/download", "![](/api/attachments")) if s.description.present?
+    end
+  end
+end