回形針：刪除附件和「不能轉換成零字符串」錯誤

我使用回形針和這裏就是我在模型中刪除附件做：回形針：刪除附件和「不能轉換成零字符串」錯誤

def before_save 
    self.avatar = nil if @delete_avatar == 1.to_s 
    end

工作正常，除非@delete_avatar標誌設置時。用戶實際上是將圖像上載（因此模型同時接收params[:user][:avatar]和params[:user][:delete_avatar]這將導致以下錯誤：

TypeError: can't convert nil into String 
    from /Work/project/src/vendor/plugins/paperclip/lib/paperclip/storage.rb:40:in `dirname' 
    from /Work/project/src/vendor/plugins/paperclip/lib/paperclip/storage.rb:40:in `flush_writes' 
    from /Work/project/src/vendor/plugins/paperclip/lib/paperclip/storage.rb:38:in `each' 
    from /Work/project/src/vendor/plugins/paperclip/lib/paperclip/storage.rb:38:in `flush_writes' 
    from /Work/project/src/vendor/plugins/paperclip/lib/paperclip/attachment.rb:144:in `save' 
    from /Work/project/src/vendor/plugins/paperclip/lib/paperclip/attachment.rb:162:in `destroy' 
    from /Work/project/src/app/models/user.rb:72:in `before_save' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/callbacks.rb:347:in `send' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/callbacks.rb:347:in `callback' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/callbacks.rb:249:in `create_or_update' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:2538:in `save_without_validation' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/validations.rb:1078:in `save_without_dirty' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/dirty.rb:79:in `save_without_transactions' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:229:in `send' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:229:in `with_transaction_returning_status' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/connection_adapters/abstract/database_statements.rb:136:in `transaction' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:182:in `transaction' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:228:in `with_transaction_returning_status' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:196:in `save' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:208:in `rollback_active_record_state!' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/transactions.rb:196:in `save' 
    from /usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:723:in `create'

我認爲它有事情做與avatar.dirty?價值，因爲當它是千真萬確w ^如果發生這種情況。問題是，如果有更改要保存，並且在設置標誌時中止頭像上傳，我該如何完全重置該事物？

來源

2010-04-26 snitko

在哈希上傳文件的樣式回形針隊列：

{:original=>#<File:/tmp/stream20100427-6708-17hkcjs-0,6708,0>, .... }

當你刪除文件這個哈希不被清除。所以使用需要手動執行：

def before_save 
    if @delete_avatar == 1.to_s 
     self.avatar.queued_for_write.clear 
     self.avatar = nil 
    end 
    end

來源

2010-04-27 19:50:19 Voyta

謝謝，解決方案是正確的，除了我不得不切換self.avatar = nil和self.avatar.queued_for_write.clear行。否則會發生相同的錯誤。 – snitko 2010-04-27 21:21:40

嗯，我只測試它在手動分配的文件，而不是從表單上傳。可能是這個問題。答案中的切換線，所以queued_for_write.clear首先進行。 – Voyta 2010-04-27 21:42:15

回形針：刪除附件和「不能轉換成零字符串」錯誤

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