Ruby Parameter Passing - ruby-on-rails

Question

I currently have the following snippets of code:
<tbody>
<% #requests.each do |request| %>
<% #user = User.where(id: request[:student_id_id]).first %>
<tr>
<td><%= #user.last_name.titleize %></td>
<td><%= #user.first_name.titleize %></td>
<td><%= #user.preferred_name.titleize %></td>
<td><%= render :partial => 'documents/resumelink' %></td>
<td><%= mail_to #user.email.downcase %></td>
<% if request.allowed_companies.nil? || request.allowed_companies.empty? %>
<td> <a class="no_selected_companies_button">No Restrictions</a></td>
<% else %>
<% #allowed_request = AllowedRequest.where(professor_id_id: #current_user[:id], student_id_id: #user[:id]).first %>
<td><%= link_to("View Companies", allowed_request_path(#allowed_request) , class: "selected_companies_button") %></td>
<% end %>
</tr>
<% end %>
</tbody>
in a partial view. The documents/_resumelink partial looks like this:
<% if (#document != nil) && (#document.resume_file_name != nil) %>
<%= link_to 'View Resume', #document.resume.url %>
<% else %>
<%= link_to 'No Resume available', '#' %>
<% end %>
In the documents_controller I have it so it will before_action set_document (with no exceptions). That definition looks like:
def set_document(user=#current_user)
#document = Document.find_by owner_user_id_id: user[:id]
end
So, what I want to be able to do is pass the #user variable to my set_document function in the render: partial => 'documents/resumelink' line in the first view and have it display a link to the resume (if there is one).
Any ideas?

Answer 1

I think your issue is more systemic than specific; and as such I'd like to give some ideas
Controller
When you use before_action, it runs before your Rails action is run
This means when you send a request to Rails, it loads the before_action filter, and then the relevant action that you've requested. Partials do not form part of this process:
This means if you want to make various variables available to different parts of your application, you need to appreciate that it works as follows:
Request -> Router -> Controller#Action -> View -> Partial
To make use of the appropriate data, you need to ensure it's defined at the correctpart of the above process. The problem you have is you're not doing that -- how can you make the #user variable available to a method before the #user variable has been defined?
This is not a specific issue for you now; but will be something you will need to keep in mind for next time.
Partial
If you're looking to include data in a partial, you will need to use the locals argument for the render method:
<%= render partial: "documents/resumelink", locals: { your_local_var: #value } %>
--
So, what I want to be able to do is pass the #user variable to my set_document function in the render
As per my simple flow chart above, your partial will not invoke the set_document method, as a partial is literally just an extension of your view
You'll need to have the #user variable set in the controller (I set the ActiveRecord association for you) and then pass it as a local to your partial:
#app/models/request.rb
Class Request < ActiveRecord::Base
has_many :users, foreign_key: "student_id_id"
end
#app/models/user.rb
Class User < ActiveRecord::Base
belongs_to :request, foreign_key: "student_id_id"
end
#app/controllers/documents_conroller.rb
Class DocumentsController < ApplicationController
before_action :set_document
def index
#requests = Request.all
end
private
def set_document(user=#current_user)
#document = Document.find_by owner_user_id_id: user[:id]
end
end
This will allow you to call the following:
#app/views/requests/index.html.erb
<% #requests.each do |request| %>
<% user = request.users.first %>
<%= render partial: "documents/resumelink", locals: {user: user} %>
<% end %>

Answer 2

You can do this way
<%= render :partial => 'documents/resumelink', :locals => {user => #user} %>
A variable user will be accessible in the partial.
Another way:
Variable #user is accessible without any changes in your code, because it is instance variable (not local)

Answer 3

If I understand what you're trying to do, I would do it differently.
Assigning variables (especially instance vars) in views is not a good practice, making DB queries from views is also quite bad.
What you can do instead is:
#requests = Request.where(your_conditions).includes(users: :documents)
and then i a view you can do
#requests.each do |request|
request.user.email
render partial: 'documents/resumelink', document: request.user.document
(actually you can do it already but solution proposed above will save you a lot of SQL queries)