Create Chunkfile

db/migrate/2_create_chunk_files.rb

+class CreateChunkFiles < ActiveRecord::Migration[5.1]
+  def change
+    create_table :chunk_files do |t|
+      t.integer :chunk_number, comment: '文件块数，从1开始'
+      t.integer :chunk_size, comment: '文件块的大小'
+      t.integer :current_chunk_size, comment: '当前文件块的大小'
+      t.integer :total_size, comment: '文件总大小'
+      t.string :identifier, comment: '文件标识'
+      t.string :filename, comment: '文件名'
+      t.integer :total_chunks, comment: '文件块的总个数'
+
+      t.timestamps
+    end
+  end
+end

lib/whaleback/chunk_file.rb

+# == Schema Information
+#
+# Table name: chunk_files
+#
+#  id                                   :bigint           not null, primary key
+#  chunk_number(文件块数，从1开始)      :integer
+#  chunk_size(文件块的大小)             :integer
+#  current_chunk_size(当前文件块的大小) :integer
+#  total_size(文件总大小)               :integer
+#  identifier(文件标识)                 :string(255)
+#  filename(文件名)                     :string(255)
+#  total_chunks(文件块的总个数)         :integer
+#  created_at                           :datetime         not null
+#  updated_at                           :datetime         not null
+#
+module Whaleback
+  class ChunkFile < ApplicationRecord
+    LocalPath = './public/chunk_file'.freeze
+    attr_accessor :io
+    after_save :write_file
+
+    def folder
+      File.join(ChunkFile::LocalPath, identifier)
+    end
+
+    def file_path
+      File.join(folder, filename)
+    end
+
+    def chunk_file_path
+      File.join(folder, "#{filename}.part#{chunk_number}")
+    end
+
+    def uploading_file_path
+      File.join(floer, "#{filename}.part#{chunk_number}.loading")
+    end
+
+    def all_finish?
+      finish_indexs = Dir['./*.part?'].map { |path| /.part(\d+)/.match(path)[1] }.sort
+      finish_indexs == (1..total_chunks)
+    end
+
+    def finish_loading
+      File.rename(uploading_file_path, chunk_file_path)
+    end
+
+    private
+
+    def write_file
+      FileUtils.mkdir_p folder
+      File.open(uploading_file_path, 'wb') do |file|
+        file.write(@io)
+      end
+      finish_loading
+      merge_file if all_finish?
+    end
+
+    def merge_file
+      FileUtils.remove file_path, force: true
+      (1..chunk_number).each do |index|
+        File.open(filepath, 'ab') do |file|
+          file.write File.open("#{file_path}.part#{index}", 'rb').read
+        end
+      end
+      save_attachment
+    end
+
+    def save_attachment filepath
+      mime_type = Rack::Mime.mime_type(File.extname(filepath))
+      case mime_type
+      when /^image/
+        attachment = Image.new
+      when /^video/
+        attachment = Video.new
+      else
+        attachment = Document.new
+      end
+      attachment.file = File.open(filepath, 'rb')
+      attachment.creator = current_auth
+      attachment.save!
+    end
+  end
+end