与图像上传器的多步骤形式

Question

我想要在第二步中通过头像上传来构建3步用户注册。所以我按照Ryan Bates的指导http://railscasts.com/episodes/217-multistep-forms。我正在使用CarrierWave gem来处理上传。但似乎我不能在用户会话中存储上传的文件信息（我越来越无法转储文件错误）。我在控制器中使用以下技术

它确实有帮助。但是，当我上载禁止的文件类型一切都崩溃在这条线

@uploader.store!(params[:user][:img_path]) 

与此错误

CarrierWave::IntegrityError in UsersController#create 
You are not allowed to upload "docx" files, allowed types: ["jpg", "jpeg", "gif", "png"] 

，而不是正常的表单验证错误。

我该如何解决这个问题？谢谢 ！

Answer 1

其实我解决了我的问题。下面是使用carrierwave

if params[:user][:img_path] 
    @uploaded = params[:user][:img_path] 
    params[:user].delete(:img_path) 
end 
session[:user_data].deep_merge!(params[:user]) if params[:user] 
@user = User.new(session[:user_data])  

if @uploaded 
    # here how validation will work 
    @user.img_path = @uploaded 
end 
@user.current_stage = session[:register_stage] 
if @user.valid? 
    if @user.last_stage? 
    @user.img_path = session[:img] if @user.last_stage? 
    @user.save 
    else 
    @user.next_stage 
    end 
    # now we can store carrierwave object in session 
    session[:img] = @user.img_path 
    session[:register_stage] = @user.current_stage 
end 

Answer 2

这可能是有点晚了OP工作代码为多步的形式与文件上传，但希望这可以帮助别人。我需要在用户会话中存储上传的图像（同样也是一个多步骤的形式），我也开始使用Ryan的Railscast #217，但该应用程序很快就演变了。请注意，我的环境是Ruby 2上的Rails 4，使用Carrierwave和MiniMagick，以及activerecord-session_store，我将在下面解释。

我相信我和OP都有的问题是，我们试图将所有的POST参数添加到用户的会话中，但是通过文件上传，其中一个参数是实际的UploadedFile对象，这是方式为了那个大。下面介绍的方法是解决这个问题的另一种方法。

声明：正如人们普遍注意到的那样，将复杂对象存储在用户会话中并不理想，最好存储记录标识符或其他标识符数据（例如图像路径），并在需要时查找该数据。这使会话和模型/数据库数据保持同步（一个非平凡的任务）和默认的Rails会话存储（使用Cookie）的两个主要原因被限制为4kb。

我的模型（submission.rb）：

class Submission < ActiveRecord::Base 
    mount_uploader :image_original, ImageUploader 
    # ... 
end 

控制器（submissions_controller.rb）：

def create 
    # If the submission POST contains an image, set it as an instance variable, 
    # because we're going to remove it from the params 
    if params[:submission] && params[:submission][:image_original] && !params[:submission][:image_original].is_a?(String) 
    # Store the UploadedFile object as an instance variable 
    @image = params[:submission][:image_original] 
    # Remove the uploaded object from the submission POST params, since we 
    # don't want to merge the whole object into the user's session 
    params[:submission].delete(:image_original) 
    end 

    # Merge existing session with POST params 
    session[:submission_params].deep_merge!(params[:submission]) if params[:submission] 

    # Instantiate model from newly merged session/params 
    @submission = Submission.new(session[:submission_params]) 
    # Increment the current step in the session form 
    @submission.current_step = session[:submission_step] 

    # ... other steps in the form 

    # After deep_merge, bring back the image 
    if @image 
    # This adds the image back to the Carrierwave mounted uploader (which 
    # re-runs any processing/versions specified in the uploader class): 
    @submission.image_original = @image 
    # The mounted uploader now has the image stored in the Carrierwave cache, 
    # and provides us with the cache identifier, which is what we will save 
    # in our session: 
    session[:submission_params][:image_original] = @submission.image_original_cache 
    session[:image_processed_cached] = @submission.image_original.url(:image_processed) 
    end 

    # ... other steps in the form 

    # If we're on the last step of the form, fetch the image and save the model 
    if @submission.last_step? 
    # Re-populate the Carrierwave uploader's cache with the cache identifier 
    # saved in the session 
    @submission.image_original_cache = session[:submission_params][:image_original] 
    # Save the model 
    @submission.save 
    # ... render/redirect_to ... 
    end 
end 

我上传的文件大多由一些自定义的处理库存。注意：为了增强会话，我使用了activerecord-session_store，它是从v4中的Rails核心提取的一个提供数据库支持的会话存储（从而增加4kb会话限制）的gem。按照the documentation的安装说明，但在我的情况下，它是非常快速和无痛的设置，并忘记它。注意高流量用户：剩余会话记录似乎没有被gem清除，所以如果你获得足够的流量，这个表可能会膨胀到无数的行。