Avatar (picture) can't be blank after avatar attached and form submitted - carrierwave error

Question

I am a newbie in Rails. I use Rails 4.2 with Ruby 2.0, I've installed the carrierwave gem. I followed the instructions how to setup with devise.

But the validation or the picture does not work correctly, cause I always get the "Avatar can't be blank" error message when I attached a picture and submit the form. I have no idea where is my mistake.

User model:

class User < ActiveRecord::Base
mount_uploader :avatar, AvatarUploader

# Include default devise modules. Others available are:
# :confirmable, :lockable, :timeoutable and :omniauthable
devise :database_authenticatable, :registerable, :recoverable, :rememberable, :trackable, :validatable, 
       :omniauthable, :omniauth_providers => [:facebook, :google_oauth2]

after_initialize :set_default_role, :if => :new_record?

# Validations
validates_presence_of   :avatar
validates_integrity_of  :avatar
validates_processing_of :avatar

def self.from_omniauth(auth)
    where(provider: auth.provider, uid: auth.uid).first_or_create do |user|
        user.name = auth.info.nickname
        user.email = auth.info.email
        user.password = Devise.friendly_token[0,20]
    end
end

end

Sign up form

    <h2>Sign up</h2>

<%= form_for(resource, as: resource_name, url: registration_path(resource_name), html: { multipart: true }) do |f| %>
  <%= devise_error_messages! %>

  <div class="field">
    <%= f.label :name %><br />
    <%= f.text_field :name, autofocus: true %>
  </div>

  <div class="field">
    <%= f.label 'Woman' %><br />
    <%= f.radio_button :gender, 'Woman' %>
    <br>
    <%= f.label 'Man' %><br />
    <%= f.radio_button :gender, 'Man' %>
  </div>

  <div class="field">
    <%= f.label :email %><br />
    <%= f.email_field :email %>
  </div>

  <div class="field">
    <%= f.label :phone %><br />
    <%= f.text_field :phone %>
  </div>

  <div class="field">
    <%= f.label :password %>
    <% if @minimum_password_length %>
    <em>(<%= @minimum_password_length %> characters minimum)</em>
    <% end %><br />
    <%= f.password_field :password, autocomplete: "off" %>
  </div>

  <div class="field">
    <%= f.label :password_confirmation %><br />
    <%= f.password_field :password_confirmation, autocomplete: "off" %>
  </div>

  <div class="field">
    <%= f.label :city %><br />
    <%= f.text_field :city %>
  </div>

  <div class="field">
    <%= f.label :county %><br />
    <%= f.text_field :county %>
  </div>

  <div class="field">
    <label>My Avatar</label>
    <%= f.file_field :avatar %>
    <%= f.hidden_field :avatar_cache %>
  </div>

  <div class="actions">
    <%= f.submit "Sign up" %>
  </div>
<% end %>

<%= render "users/shared/links" %>

Application controller's strong parameters:

  def configure_permitted_parameters
      devise_parameter_sanitizer.for(:sign_in) { |u| u.permit(:email) }
      devise_parameter_sanitizer.for(:sign_up) { |u| u.permit({ roles: [] }, :name, :email, :password, :password_confirmation, :avatar, :avatar_cache) }
      devise_parameter_sanitizer.for(:account_update) { |u| u.permit({ roles: [] }, :name, :email, :password, :password_confirmation, :avatar, :avatar_cache) }
  end

I really do not see where is my mistake. Maybe do you see?

Answer 1

Because you have this validation:

validates_presence_of :avatar

means, you have to upload an avatar.

You will get this error message: Avatar can't be blank if you try to submit the form without attaching the avatar.

So, make sure you attach an avatar before hitting the Sign Up button.