如何讀取CSV文件作為rake任務並實例化模型類？ -獲取ActiveRecord連接錯誤

Question

我正在編寫一個Ruby on Rails應用程序，該應用程序具有可以解析CSV文件的Rake任務。

這是代碼：

 desc "Import Channels into DB\n Usage: rake channel_import"
 task :import_channels, :path_to_channel_list do |t, args|

 require "#{Rails.root}/app/models/channel"
 require "csv"
 filePath = args.path_to_channel_list
 puts "Filepath received = #{filePath}"
csv = CSV.read("#{filePath}", :encoding => 'windows-1251:utf-8')
  csv.each_with_index do |row, i|
 if [0].include?(i)
      puts "Skipping over row #{i}"
      next
     end
     if(row.nil?)
      puts "row[#{i}] was nil"
     else
channelName = nil
      classif = nil
      owner = nil
      channelName = row[0].force_encoding('UTF-8')
      classif = row[1].force_encoding('UTF-8')
      owner = row[2].force_encoding('UTF-8') 
      if (channelName.nil?)
        puts "Channel name for row #{i} was nil"
        #add entry to Log file or errors database
        next #skip this row of the csv file and go to next row
      else
        channel_hash = Hash.new("name" =>"#{channelName}", "classification" => "#{classif}", "owner" => "#{owner}" )

      end
       puts "\nChannel Name = #{channelName}\nClassification = #{classif}\n Ownership = #{owner}"
      #If channel name exists in the Database, update it
      xisting_channel = nil
      xisting_channel = Channel.find_by channel_name: '#{channelName}'
      if(xisting_channel.nil?)
          #create a new channel
      @new_channel = Channel.create(channel_hash) 
      puts "Inserted....#{@new_channel.inspect}"
      else
          #update existing channel
          Channel.update(xisting_channel.id, :classification => "#{classif}", :ownership => "#{owner}" )
          puts "Updated...."
          puts "channel_hash = #{channel_hash.inspect} "
      end#end if/else

  end#end if/else

 end #end CSV.each


 end

當我運行此代碼時，出現以下錯誤消息：

 MRMIOMP0903:am AM$ rake import_channels[/XXXXXXXX/Channellist.csv]
 Filepath received = /XXXXXXX/Channellist.csv
 Skipping over row 0

 Channel Name = APTN HD+
 Classification = Specialty
 Ownership = Aboriginal Peoples Television Network
 rake aborted!
 ActiveRecord::ConnectionNotEstablished

我嘗試使用IRB創建Channel對象，並且效果很好。 數據庫已創建，我正在使用MySQL WorkBench看到它。 所有表都在那里，但是，我無法從Rake任務中創建Channel對象。

我的假設是，也許在某個文件夾/層次結構之外，該應用無法訪問ActiveRecord :: Base類或類似的東西。

關於如何進行這項工作的任何建議？

更新：

---

根據菲利普·霍爾斯特倫的答案

我更改了頂行以加載環境

 task   :import_channels => :environment do|t, args|

然后嘗試rake import_channels並得到此錯誤：

rake aborted!
undefined method `safe_constantize' for #<Hash:0x007fbeacd89920>

Answer 1

您需要在運行Rake任務之前加載環境。 我不熟悉您的多個任務名稱選項，但是對於一個簡單的示例，您需要這樣做：

task : import_channels => :environment do