资源下载增加is_pdf参数

app/controllers/files_controller.rb

@@ -260,7 +260,12 @@ class FilesController < ApplicationController
 
     return normal_status(-2, "该课程下没有id为 #{params[:id]}的资源") if @file.nil?
     return normal_status(403, "您没有权限进行该操作") if @user != @file.author && !@user.teacher_of_course?(@course) && !@file.public?
-
+    @is_pdf = false
+    file_content_type = @file.content_type
+    file_ext_type = File.extname(@file.filename).strip.downcase[1..-1]
+    if (file_content_type.present? && file_content_type.downcase.include?("pdf")) || (file_ext_type.present? && file_ext_type.include?("pdf"))
+      @is_pdf = true
+    end
     @attachment_histories = @file.attachment_histories
   end
 

app/views/files/histories.json.jbuilder

@@ -1,2 +1,3 @@
+json.is_pdf @is_pdf
 json.partial! 'attachments/attachment_small', attachment: @file
 json.partial! "attachment_histories/list", attachment_histories: @attachment_histories