"undefined method `model_name' for NilClass:Class" with CarrierWave

Question

Now I'm using CarrierWave for upload photos to my site. The problem is that when I open photos/upload (upload.html.erb) show me this error:

undefined method `model_name' for NilClass:Class

Around the line 1 of my upload.html.erb:

<%= form_for @photos, :html => {:multipart => true} do |f| %>  
  <%= f.error_messages %>  
  <%= f.hidden_field :gallery_id %>  
  <p>  
    <%= f.label :name %><br />  
    <%= f.text_field :name %>  
  </p>  
  <p>  
    <%= f.file_field :photo %>  
  </p>  
  <p><%= f.submit %></p>  
<% end %>

I don't really understand this, because I think that my model (photos.rb) hasn't got errors:

class Photos < ActiveRecord::Base
  attr_accessor :gallery_id, :name, :photo
  belongs_to :gallery
  mount_uploader :photos, PhotosUploader
end

In my photos_controller.rb I have this:

class PhotosController < ApplicationController
  def new
    @photos = Photos.new(:gallery_id => params[:gallery_id])
  end

  def create
    @photos = Photos.new(params[:photos])
    if @photos.save
      flash[:notice] = "Successfully created Photos."
    else
      render :action => 'new'
    end
  end

  def edit
    @photos = Photos.find(params[:id])
  end
  def update
    @photos = Photos.find(params[:id])
    if @photos.update_attributes(params[:photos])
      flash[:notice] = "Successfully updated Photos."
    else
      render :action => 'edit'
    end
  end

  def destroy
    @photos = Photos.find(params[:id])
    @photos.destroy
    flash[:notice] = "Successfully destroyed Photos."
  end
end

And this my photos_uploader.rb:

class PhotosUploader < CarrierWave::Uploader::Base
  include CarrierWave::RMagick
  storage :file
  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end  
  version :thumb do
    process :scale => [180, 180]
  end
end

Regards, Iván

Are your migrations etc. sorted OK?

Michael De Silva
– Michael De Silva

2011-06-23 17:49:35 +00:00
Commented Jun 23, 2011 at 17:49 — Michael De Silva
– Michael De Silva, Commented Jun 23, 2011 at 17:49
Yes, I have make my migrations.

Ivanhercaz
– Ivanhercaz

2011-06-24 14:39:09 +00:00
Commented Jun 24, 2011 at 14:39 — Ivanhercaz
– Ivanhercaz, Commented Jun 24, 2011 at 14:39

Luke · Accepted Answer · 2011-06-23 19:15:04Z

4

The problem could have something to do with the fact that you've mounted the uploader as :photos, but the form field is :photo. Try making these match.

answered Jun 23, 2011 at 19:15

Luke

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4 Comments

Ivanhercaz Over a year ago

Yes, a small error, sorry. But, when I change :photo to :photos, the error continue. I will keep looking for the error.

Luke Over a year ago

Also, your model is named Photos and should really be named Photo. Models names are singular by convention in Rails and this could be the reason it can't find the correct model. It also makes everything a little more confusing when I'm trying to look for inconsistencies. Try changing this and updating your question to match.

Michael De Silva Over a year ago

Good eye Luke. As for the fields, he's got them defined correctly attr_accessor :gallery_id, :name, :photo. Yes, the model needs to be singular.

Alex Siri Over a year ago

This may not solve the problem, but it will give us a better idea on what the error might be.

gauravsingh2012 · Accepted Answer · 2012-02-26 03:15:42Z

1

The Problem can be fixed by instantiating the object photo object. I think that should fix the problem.

answered Feb 26, 2012 at 3:15

gauravsingh2012

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Comments

Sachin Singh · Accepted Answer · 2013-07-27 20:48:21Z

1

I am answering it late as in can see there is no upload action in photos controller that matches with template upload.html.erb

I suggest you to rename it to new.html.erb and try accessing the url 'photos/new'

answered Jul 27, 2013 at 20:48

Sachin Singh

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Comments

roxdurazo · Accepted Answer · 2018-06-13 20:17:10Z

0

I had the same problem and searching got me to this answer https://stackoverflow.com/a/21992187/3280686

You need to add this on your Class PhotosUploader

include CarrierWaveDirect::Uploader
include ActiveModel::Conversion
extend ActiveModel::Naming

answered Jun 13, 2018 at 20:17

roxdurazo

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