Could not find a valid mapping for nil

Question

So, I'm using carrier wave to allow users to upload profile images. Now ultimately, I'd like the user to be able to click on the image and upload a new one on the fly in the profile.html.haml page.

So, I've tried the below adding a form with a put action to let the user update the image on the fly without having to go to the edit.html.haml page.

However, I'm being hit with this error:

Could not find a valid mapping for nil

Extracted source (around line #8):




<%= form_for(@user, :url => registration_path(@user), :html => { :method => :put }, :html => {:multipart => true}) do |f| %>
<%= link_to (image_tag current_user.profile_image_url(:thumb).to_s), edit_account_path(current_user)%>
<% end %>

Where did I go wrong?

Alternatively I've tried this which might be totally off:

 <%= link_to (image_tag current_user.profile_image_url(:thumb).to_s), f.file_field :profile_image%>     

which gave this error:

Sites/Friendiose-master/app/views/home/landing_welcome.html.erb:9: syntax error, unexpected tSYMBEG, expecting ')'
...l(:thumb).to_s), f.file_field :profile_image);@output_buffer...

Thanks in advanced.

Answer 1

So firstly, what do you think this error might me. Most common errors ever:

Sites/Friendiose-master/app/views/home/landing_welcome.html.erb:9: syntax error, unexpected tSYMBEG, expecting ')'
...l(:thumb).to_s), f.file_field :profile_image);@output_buffer...

I'm not going to give you full answer but teach you to think how you can debug it.

https://github.com/carrierwaveuploader/carrierwave

That is the documentation for carrierwave. When showing the image it says the following:

    <%= form_for @user, :html => {:multipart => true} do |f| %>
  <p>
    <label>My Avatar</label>
    <%= image_tag(@user.avatar_url) if @user.avatar? %>
    <%= f.file_field :avatar %>
    <%= f.hidden_field :avatar_cache %>
  </p>
<% end %>

One tip and this is not me being sarcastic but get used to reading alot and googling even more. I haven't used paperclip but I can see the issues from 2 mins googling.

Ruby on Rails using link_to with image_tag

There is how to create a link with an image.

From that link look at the difference between yours:

<%= link_to (image_tag current_user.profile_image_url(:thumb).to_s), edit_account_path(current_user)%>

and the correct way:

<%=link_to( image_tag(participant.user.profile_pic.url(:small)), user_path(participant.user), :class=>"work") %>

What does the error say you are missing?

It is not always great to give people an answer straight away but the keys on how to figure it out.