<AbstractController::DoubleRenderError 在控制器

Question

我收到此错误，我尝试添加一个 redirect_to() 并返回我的 access_doc_or_redirect() 方法，但没有运气。有什么建议吗？

 def access_doc_or_redirect(doc_id, msg)
   doc = Document.find(params[:id])
   if doc.user_access?(current_user)
     @document = doc
   else
     flash[:alert] = msg
     redirect_to root_url and return
   end
 end

 def get
   access_doc_or_redirect(params[:id], "Sorry, no document view access.")
   redirect_to @document.file.url
 end

错误

access_doc_or_redirect(params[:id], "Sorry, no document view access" AbstractController::DoubleRenderError: 在此操作中多次调用渲染和/或重定向。请注意，您只能调用渲染或重定向，并且在每个动作最多一次。还要注意，重定向和渲染都不会终止动作的执行，所以如果你想在重定向后退出一个动作，你需要做一些类似“redirect_to(...) and return”的事情。

Answer 1

AbstractController::DoubleRenderError：在此操作中多次调用渲染和/或重定向。

错误是自我描述的，您在操作中多次调用渲染或重定向。让我们看看你的方法：

def access_doc_or_redirect(doc_id, msg)
  doc = Document.find(params[:id])
  if doc.user_access?(current_user)
    @document = doc  
    #this block will run fine and return @document to get method
  else
    flash[:alert] = msg
    redirect_to root_url and return
    #this block is giving you trouble because you are redirecting to root url and then control goes back to your get method where you are using redirect again and hence double render error
  end
end

修复：

如果您将其用作过滤器，那么您可以执行以下操作来修复错误：

def get
  #i think this is your main method so you should use redirect or render inside this method only
  #instance variables set inside access_doc_or_redirect will automatically be available inside this method
  if @document 
    redirect_to @document.file.url
  else
    flash[:alert] = "Sorry, no document view access."
    redirect_to root_url
  end
end

def access_doc_or_redirect
  @doc = Document.find(params[:id])
  if @doc.user_access?(current_user)
    @document = doc
  end
end