Question

我有一个表示文档的模型，标题，作者等从Web表中删除，但内容需要从时间和资源密集的PDF中提取。这似乎是使用delayed_jobs的合理位置，但它总是失败，所以我想知道是否存在我缺少的限制或GCE

#working code
doc = Document.new
doc.title = html_table.row[i].title
doc.author = html_table.row[i].author
doc.link = html_table.row[i].link
doc.load_pdf_text  # instance method which used the link extracted above to dowload a pdf and strip the text 
doc.save

以上代码无需任何更改即可运行。我认为延迟作业允许用send_later调用替换直接方法调用并继续

#broken code
#same as above except
doc.send_later(:load_pdf_text)

此代码将始终失败作业，并且会抱怨访问作为模型一部分的私有方法，例如，下载PDF需要URL。任何指针都将非常感激。

添加了：

方法定义（链接和摘要是Document模型的数据库支持属性）

def load_pdf_text
  tmpfilename = "#{RAILS_ROOT}/tmp/tmp_"+Time.now.to_s.gsub(/ |-/,"_")
  Kernel.system("curl -s #{link} > #{tmpfilename}") # this is line 224
  a=""
  IO.popen("pdftotext -raw -l 1 #{tmpfilename} -"){ |pipe| a = pipe.read }
  Kernel.system("rm #{tmpfilename}")
  summary = a
  save
end

错误消息

--- !ruby/struct:Delayed::PerformableMethod 
object: AR:Memo:4089
method: :load_pdf_text
args: []

 | Attempt to call private method
/Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/attribute_methods.rb:236:in `method_missing'
/Users/naven87/test/memos/app/models/memo.rb:224:in `load_pdf_text'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/performable_method.rb:23:in `send'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/performable_method.rb:23:in `perform'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/job.rb:215:in `invoke_job'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/job.rb:93:in `run_with_lock'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/timeout.rb:62:in `timeout'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/job.rb:93:in `run_with_lock'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/benchmark.rb:308:in `realtime'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/job.rb:92:in `run_with_lock'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/job.rb:153:in `reserve_and_run_one_job'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/job.rb:152:in `each'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/job.rb:152:in `reserve_and_run_one_job'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/job.rb:199:in `work_off'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/job.rb:198:in `times'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/job.rb:198:in `work_off'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/worker.rb:28:in `start'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/benchmark.rb:308:in `realtime'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/worker.rb:27:in `start'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/worker.rb:24:in `loop'
/Library/Ruby/Gems/1.8/gems/delayed_job-1.8.4/lib/delayed/worker.rb:24:in `start'
/Users/naven87/.gem/ruby/1.8/gems/collectiveidea-delayed_job-1.8.2/lib/delayed/tasks.rb:13
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `call'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `execute'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `each'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `execute'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_chain'
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/monitor.rb:242:in `synchronize'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in `invoke'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run'
/Library/Ruby/Gems/1.8/gems/rake-0.8.7/bin/rake:31
/usr/bin/rake:19:in `load'
/usr/bin/rake:19

Answer 1

基于进一步调查，似乎当延迟作业序列化对象并反序列化以实际发送消息时，它不再在同一范围内，并且它不能访问该对象的任何私有实例方法。这是令人困惑的，因为你没有通过延迟的工作运行它，它会工作查找，但一旦传递到延迟的工作它不再作为运行方法本身的对象，而是发送方法到对象创建一个不同的集合权限。你需要将实例方法设为公共或提供一个公共机制，延迟作业可以用来做任何非私有的操作。

Answer 2

请在此处发布错误消息，如果可能，请在模型源中发布。在此期间，您可以通过将方法和参数作为显式消息发送到doc来解决此问题：

doc.send :send_later, :extract_pdf_text

但这不是解决方案。您应该重构代码，这样就不会出现这些错误。

让延迟作业在模型中工作

2 个答案: