在 Rails4 中如何在一个控制器动作中分配变量并在另一个控制器动作中使用它的值

Question

使用 Ruby on Rails 4，我有一个 UI，用户可以在其中从服务器上的目录路径中选择视频文件。然后，他们单击一个按钮，该按钮在文件上运行媒体信息并显示视频的 xml，同时解析 xml 中的某些数据值并将该值分配给 @variables 并将其显示在 UI html 页面中。这一切都在“评估媒体”的动作/方法中完成。当页面加载回来时，它会确定该文件是否已保存，并允许用户将文件名、路径和媒体信息属性保存到 mysql 中的表中。当您单击保存按钮时，它会调用动作/方法“save_file”。当我尝试将这些变量值分配给模型类字段以插入表中（在控制器内）时。不读取值。它只插入空值。如何 我可以让这些在“evaluate_media”操作中分配的变量值也可用于“save_file”操作或同一控制器中的任何其他操作吗？根据它们的设置和定义方式，我认为它们在模型/控制器对象“file_alias_tfile”的范围内可用。

在“save_file”操作中，我尝试使用 3 种不同的方式分配值：

    full_path = params[:filepath2]  <--This one puts a NULL into the table  
    src_location = @radio_button_value  <--This one puts a NULL into the table
    directory = "#{@dir_path_choice}"  <--This one doesn't even get called into the insert script and nothing is inthe column on insert. (I don't get errors and a record does geet inserted with the other good values.)into the table

这是我尝试将变量值分配给模型字段的 save_file 操作/方法代码：

  def save_file    

        src_location = @radio_button_value
        directory = "#{@dir_path_choice}"
        full_path = params[:filepath2]
 #       "#{@filepathname}"
        full_filename = "#{@filepath}"
        alias_code = "#{@file_alias}"
        validate_status = "#{@file_status}" 
        error_msg = "#{@file_msg}"
        video_alias_match = "#{@msg_dtl1}" 
    audio_alias_match = "#{@msg_dtl2}" 
    video_format = "#{@video_format}" 
    video_bitrate = "#{@video_bitrate}" 
    video_width = "#{@video_width}"
    video_height = "#{@video_height}" 
    video_framerate = "#{@video_framerate}" 
    video_aspect_ratio = "#{@video_aspectratio}" 
    video_scan_type = "#{@video_scantype}"
    video_scan_order = "#{@video_scanorder}" 

    @file_alias_tfile = FileAliasTfile.new( :src_location => src_location, :directory => directory, :full_path => full_path, :full_filename => full_filename, :file_ext => '', 
                                                  :assigned_status => 'Unassigned', :file_status => 'Saved', :alias_code => alias_code, :validate_status => validate_status, :error_msg => error_msg, 
                                                  :video_alias_match => video_alias_match, :audio_alias_match => audio_alias_match, :video_format => video_format, :video_bitrate => video_bitrate, 
                                                  :video_width => video_width, :video_height => video_height, :video_framerate => video_framerate, :video_aspect_ratio => video_aspect_ratio, 
                                                  :video_scan_type => video_scan_type, :video_scan_order => video_scan_order, :video_alias_code => '', :audio_alias_code => '', 
                                                  :bus_prod_initiative_id => 0, :status => 'Active', :start_date => DateTime.now.to_date, :end_date => '', :deleted_b => 0, 
                                                  :created_by => 'admin', :updated_by => 'admin')

@file_alias_tfile = FileAliasTfile.create(file_alias_tfile_params)

if @file_alias_tfile.save
  redirect_to mainpages_home_path, :notice => "The file alias validation has been saved."
else
  redirect_to alias_mainpages_home_path, :notice => "The file alias validation has been saved."

# 渲染 = "索引" 结尾 结束

这里是 'evaluate_media' 方法，其中定义了上面在 save_file 中调用的值：

定义评估媒体 @state = '发布' @radio_button_value = 参数[:location]

 #Determine if file chosen has been saved to database yet.
 @stored_file = FileAliasTfile.where(:full_path => params[:filepath2], :deleted_b => 0).first

 if @stored_file.present?
    @file_exists_flag = 'Y'
    @file_exists_msg = 'This File and Alias has been saved in application.'
 else
    @file_exists_flag = 'N'
    @file_exists_msg = 'This File and Alias has NOT been saved in application yet.'
  end

      root_dir = '/watchfolder/miniprod/hot/'
      provider_dir = ""

   #Store selected value for re-display on post.
   @selected_filepath = params[:filepath2]

filepath = File.join(root_dir, provider_dir, params[:filepath])

   @filepath = File.join(params[:filepath2])  

   @media_xml = ::MediaInfo.call(@filepath)  #Filepath is sent in from the index html
   @alias_xml = ::AliasGenerator.call(@media_xml)

   @media_xml_for = ""
   @alias_xml_for = ""
   REXML::Document.new(@media_xml).write(@media_xml_for, 1)
   REXML::Document.new(@alias_xml).write(@alias_xml_for, 1)
   alias_parse_doc = ""
   media_parse_doc = ""
   alias_parse_doc = REXML::Document.new(@alias_xml)  
   media_parse_doc = REXML::Document.new(@media_xml) 


   #parse Alias XML Doc   
   # @aliasgen_ver = alias_parse_doc.elements.each("/aliasGenerator vr=/text()") { |e| e }
   @aliasgen_ver = REXML::XPath.each(alias_parse_doc, "/aliasGenerator vr=/text()") { |element| element }    
   @file_alias = REXML::XPath.each(alias_parse_doc, "*//alias/text()") { |element| element }
   @file_status = REXML::XPath.each(alias_parse_doc, "*//error/text()") { |element| element }
   @file_msg = REXML::XPath.each(alias_parse_doc, "*//error_m/text()") { |element| element }
   @msg_dtl1 = REXML::XPath.each(alias_parse_doc, "*//closestvideoalias/text()") { |element| element }
   @msg_dtl2 = REXML::XPath.each(alias_parse_doc, "*//closestaudioalias/text()") { |element| element }

   #parse Video Media Info XML Doc  
    @filepathname = REXML::XPath.each(media_parse_doc, "*//Complete_name/text()") { |element| element }  
    @video_format = REXML::XPath.each(media_parse_doc, "//track[@type='Video']/Format/text()") { |element| element }
    @video_bitrate = REXML::XPath.each(media_parse_doc, "//track[@type='Video']/Bit_rate/text()") { |element| element }  
    @video_width = REXML::XPath.each(media_parse_doc, "//track[@type='Video']/Width/text()") { |element| element } 
    @video_height = REXML::XPath.each(media_parse_doc, "//track[@type='Video']/Height/text()") { |element| element }
    @video_aspectratio = REXML::XPath.each(media_parse_doc, "//track[@type='Video']/Display_aspect_ratio/text()") { |element| element } 
    @video_framerate = REXML::XPath.each(media_parse_doc, "//track[@type='Video']/Frame_rate/text()") { |element| element } 
    @video_scantype = REXML::XPath.each(media_parse_doc, "//track[@type='Video']/Scan_type/text()") { |element| element } 
    @video_scanorder = REXML::XPath.each(media_parse_doc, "//track[@type='Video']/Scan_order/text()") { |element| element }   

   #parse Audio Media Info XML Doc 
  #  @audio_track = REXML::XPath.each(media_parse_doc, "//track[@type= 'Audio']/track/text()") { |element| element } 
 #   @track_array = REXML::XPath.each(media_parse_doc,(@audio_track)) do {|track| track.elements["Bit_rate"].text }
  #   @bitrate = track.elements["Bit_rate"].text
  #  end
    #@audio_tracknum = REXML::XPath.each(media_parse_doc, "//track[@type='Audio']/track streamid=/text()") { |element| element } 
   # @audio_format = REXML::XPath.each(media_parse_doc, "//track[@type='Audio']/Format/text()") { |element| element } 
   # @audio_bitrate = REXML::XPath.each(media_parse_doc, "//track[@type='Audio']/Bit_rate/text()") { |element| element }  
   # @audio_numchan = REXML::XPath.each(media_parse_doc, "//track[@type='Audio']/Width/text()") { |element| element } 
   # @audio_language = REXML::XPath.each(media_parse_doc, "//track[@type='Audio']/Display_aspect_ratio/text()") { |element| element } 

   render :action => :index

结束

您能否提供一个示例，说明如何正确设置变量以跨操作传递和/或如何在插入中正确地将它们分配给数据库？

感谢您的帮助！

Answer 1

我在另一个问题的搜索中找到了答案，但它仍然留下一个悬而未决的问题。

这里是其他问题和答案的链接以获取更多详细信息： Same instance variable for all actions of a controller

基本上它给了我两种方法。如果我的一个动作没有从另一个动作呈现，并且两个方法都需要访问这些值，那么我将需要定义另一种方法来分配变量，然后让 save_file 和 evaluate_media 方法调用这个新定义的方法，这样它们也可以访问变量。这是问题解决了共享相同变量的索引和显示方法的示例。

def index
  set_up_instance_variable
end

def show
  set_up_instance_variable
end

private

def set_up_instance_variable
  @some_instance_variable = foo
end

另一种解决方案是使用 before_filter：

您可以使用前置过滤器为多个操作定义实例变量，例如：

class FooController < ApplicationController
  before_filter :common_content, :only => [:index, :show]

 def common_content
    @some_instance_variable = :foo
  end
end

现在@some_instance_variable 可以从索引或显示操作呈现的所有模板（包括部分模板）中访问。