Ruby on Rails field_for Form Helper Problems - ruby-on-rails

I'm using the field_for form helper with a loop:
<% f.fields_for :permissions do |permission_form| %>
<tr>
<td><%= permission_form.object.security_module.name %><%= permission_form.hidden_field(:security_module_id) %></td>
<td><%= permission_form.object.security_module.description %></td>
<tr>
<% end %>
The resulting output of the above code is this:
<input id="role_permissions_attributes_0_id" name="role[permissions_attributes][0][id]" type="hidden" value="76" />
<tr>
<td>Diary<input id="role_permissions_attributes_0_security_module_id" name="role[permissions_attributes][0][security_module_id]" type="hidden" value="13" /></td>
<td>Access to the Diary Module</td>
</tr>
<!-- next input field then <tr> tag -->
The problem with this markup is that the input tag falls outside of the tr tag which there for causes validation issues with XHTML.
Does anyone know how I can have the input tag fall inside the tr tag therefore giving me valid XHTML 1.0 STRICT markup?
Thanks

If you take a look at the Rails source code you'll find this.
# in actionpack/lib/action_view/helpers/form_helper.rb
def fields_for_nested_model(name, object, args, block)
if object.new_record?
#template.fields_for(name, object, *args, &block)
else
#template.fields_for(name, object, *args) do |builder|
#template.concat builder.hidden_field(:id)
block.call(builder)
end
end
end
Notice it is adding the hidden field directly here, and it doesn't look like there is any option to change this behavior. The easiest thing is probably to create your own custom form builder.
# in lib/no_id_form_builder.rb
class NoIdFormBuilder < ActionView::Helpers::FormBuilder
private
def fields_for_nested_model(name, object, args, block)
#template.fields_for(name, object, *args, &block)
end
end
And then use this in your form. You'll need to add the id field manually.
<% f.fields_for :permissions, :builder => NoIdFormBuilder do |permission_form| %>
<tr>
<td>
<%= permission_form.object.security_module.name %>
<%= permission_form.hidden_field(:security_module_id) %>
<%= permission_form.hidden_field(:id) unless permission_form.object.new_record? %>
</td>
<td><%= permission_form.object.security_module.description %></td>
<tr>
<% end %>
You may want to submit a lighthouse ticket on this. perhaps there could be a :skip_id_field option to fields_for which does this.

There is a workaround available as of 2.3.5. If you explicitly place the :id field, it won't implicitly add it for you:
<% form_for #foo do |f| %>
<table>
<tbody>
<% f.fields_for :bars do |bf| %>
<tr>
<td>
<%= bf.hidden_field :id %>
<%= bf.text_field :name %>
</td>
</tr>
<% end %>
</tbody>
</table>
<% end %>
See
https://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/3259

Slight correction:
The :builder option needs to go on the form_for containing the fields_for, not the fields_for.

Related

Error when trying to link to patient profile

I'm getting an error when trying to link_to a patient profile when a provider views his patients list. I have no problem displaying all the names of the patients that belong to the provider but when trying to link to the patient profile I get an undefined method 'id'.
So the way it works is, patients can search for providers and add them to the List model. On the provider side, I just list out all the patients that added that specific provider. Here is my erb code below,
<div class="body">
<div class="body">
<% if #active_patients.count > 0 %>
<table>
<thead>
<tr>
<th>Patient Name</th>
<th>Actions</th>
</tr>
</thead>
<tbody>
<% #active_patients.each do |list| %>
<tr>
<td>
<%= list.patient.role.user.first_name %> <%= list.patient.role.user.last_name %>
</td>
<td>
<%= link_to patient_path(id: #patient.id), class: "btn" do %>View<% end %> . #### THIS IS THE LINE
</td>
</tr>
<% end %>
</tbody>
</table>
<% else %>
<div class="no-records">
<%= image_tag "icon-no-records", class: "image" %>
<div class="text">You have no patients.</div>
</div><!--no-records-->
<% end %>
</div><!--body-->
</div>
Here is my List model,
class List < ApplicationRecord
belongs_to :membershipable, :polymorphic => true
belongs_to :provider
def patient
membershipable_type=='Patient' ? membershipable : nil
end
def provider_user
patient.try(:user)
end
end
Also here's the error message ->
Let Rails do the work of building the path. Each ActiveRecord model has a to_param method which decides how the instance will be encoded in an URL. By default it returns the model id but it could also be a slug based on the title or another property of the model.
Calling your helper like patient_path(patient) should do the trick.
Additionally, in your current code, you're referring to the previously unused #patient variable, even though it looks like you want to refer to list.patient instead.
Here:
<% #active_patients.each do |list| %>
<tr>
<td>
<%= list.patient.role.user.first_name %> <%= list.patient.role.user.last_name %>
</td>
<td>
<%= link_to patient_path(id: #patient.id), class: "btn" do %>View<% end %> . #### THIS IS THE LINE
</td>
</tr>
<% end %>
you have the variable list available to you. It appears that you get the patient by doing list.patient, as you do here:
<%= list.patient.role.user.first_name %> <%= list.patient.role.user.last_name %>
But, then you try to use a variable called #patient, here:
<%= link_to patient_path(id: #patient.id), class: "btn" do %>View<% end %> .
when you don't have the variable #patient. So, you get your nil error.
Instead, it seems you should do:
<%= link_to patient_path(id: list.patient.id), class: "btn" do %>View<% end %> .
Or, as milgner points out, you could simply do:
<%= link_to patient_path(list.patient), class: "btn" do %>View<% end %> .
Also, you might want to look into the Law of Demeter, which you violate (IMO) when you do:
list.patient.role.user.first_name

rails 5 form_tag with original DB value and after new selection in form, both records must be updated

I have a form_tag with a radio_button_tag and it populates with data from DB. It must simply be directed to a customised update action(update_multiple) where a boolean column is updated for all those 2 records which have been changed in the form.
For e.g. say when initially the form was populated from DB with record 1's radio button selected and now user changed his selection to record 3, then at Submit of form tag the update of both records must occur but the problem is the code at submit, only collects id of record which is now selected in that group.How do I get id of that record also which was unselected so that I can update_all for both of them at one go?
And if Submit cannot handle this action, then is there a way in controller or form to persist the id of the initial selected record before populating the form? As you see, I've tried with collecting an array of ids[] with radio_button_tag.
TIA for your help.
Here's the form code:
<%= form_tag update_multiple_user_cv_attachments_path, method: :put, action: :update_multiple do %>
<table class="table table-bordered table-striped">
<thead>
<tr>
<th> Select a CV </th>
<th> Resume Name </th>
</tr>
</thead>
<tbody>
<% #cv_attachments.each do |cv_attachment| %>
<%= hidden_field_tag cv_attachment.main, :value => params[:main] %>
<tr>
<td><%= radio_button_tag "cv_attachment_ids[]", cv_attachment.id, cv_attachment.main %> </td>
<td><%= cv_attachment.attachment.file.basename %></td>
</tr>
<% end %>
</tbody>
</table>
<br>
<%= submit_tag "Select Main", :class =>'button' %>
<% end %>
Here's the controller update_multiple code.
def update_multiple
CvAttachment.update_all(["updated_at=?", Time.now], :id => params[:cv_attachment_ids])
end
I can think of 2 ways to achieve your objective.
update the boolean for all the attachments which belong to the user to false and then update the one which has been selected to true
include a hidden field in the form and set it to the id that is already true. Then in the controller action, update the one that is selected to true and the one in the hidden field to false. This is probably a better option and you'll probably want to wrap the d/b updates in a transaction.
<tbody>
<% #cv_attachments.each do |cv_attachment| %>
<% if cv_attachment.main %>
<%= hidden_field_tag "ex_main_cv", cv_attachment.id %>
<% end %>
<tr>
<td><%= radio_button_tag "main_cv", cv_attachment.id, cv_attachment.main %> </td>
<td><%= cv_attachment.attachment.file.basename %></td>
</tr>
<% end %>
</tbody>
controller
def update_main_attachment // probably a better name for this method
if params["ex_main_cv"] != params["main_cv"]
Attachment.transaction do
deselected_attachment = Attachment.find(params["ex_main_cv"]
deselected_attachment.update_attribute(:main, false)
selected_attachment = Attachment.find(params["main_cv"]
selected_attachment.update_attribute(:main, true)
end
end
end
Many thanks #margo. Here' how I resolved it partly your way of using hidden_field. But for now keeping this thread open as I'm making 2 DB updates for toggle of same column.
<tbody>
<% #cv_attachments.each do |cv_attachment| %>
<% if cv_attachment.main %>
<%= hidden_field_tag "ex_main", cv_attachment.id %>
<% end %>
<tr>
<td><%= radio_button_tag "new_main", cv_attachment.id, cv_attachment.main, :id => "#{cv_attachment.id}"%> </td>
<td><%= cv_attachment.attachment.file.basename %></td>
</tr>
<% end %>
</tbody>
and in controller:
def update_main
if request.put?
if params["ex_main"] != params["new_main"]
CvAttachment.find(params[:ex_main]).toggle!(:main)
CvAttachment.find(params[:new_main]).toggle!(:main)
end
end

Rails: how to render nested form in table

For example, I have two models:
class Task < ApplicationRecord
has_many :task_details
end
class TaskDetail < ApplicationRecord
belong_to :task
end
I want to display a table, each row in table is one TaskDetail and allow user input. After that user submits, all data will put to server. Here is my code:
(Note that: I #data[:task] is a task object because I want to return a hash with some information for view)
<%= form_for #data[:task], :url => tasks_path do |f| %>
<table> ... </table>
<% end %>
My question is: How can I do as my requirement.
thanks
Ensure that your Task model has accepts_nested_attributes_for :task_details and then you can do something like...
<%= form_for #data[:task], :url => tasks_path do |f| %>
<table>
<tr>
<th>Task Name</th>
<th>Task Description</th>
<tr>
<%= f.fields_for :task_details do |task_detail| %>
<tr>
<%= task_detail.hidden_field :id %>
<td><%= task_detail.text_field :name %></td>
<td><%= task_detail.text_field :description %> </td>
<tr>
<% end %>
</table>
<% end %>
Note the use of the hidden field for :id ... you need that so that rails can distinguish data from existing tasks versus a new task you're entering.
In your new method you should ensure there's at least one new task detail to provide an empty line on the form to input the detail
def new
...
#data[:task].task_details.build
...
end

Removing conditional logic from a shared partial view or alternative solution

For a current project, I have duplicate code between views, and I'm not sure of the best route to refactor it.
I appear to be in a position where I can have duplicate code across various .html.erb files, or I could put identical code into a partial and use conditionals. I've always heard logic should stay out of views. Neither option seems ideal, and I don't currently know of alternatives.
To illustrate my question, I created a simple rails app called animals. I scaffolded for two models: one for cat and one for dog. Images display their corresponding attributes:
Displaying #cats and #dogs is pretty much the same. Cats just have a column for meows while Dogs have a column for barks, and a dog has the additional attribute column of plays_catch.
Lets say we choose to reduce the duplicate code for displaying cats and dogs by making a shared view partial:
#views/shared/_animal.html.erb
<tr>
<td><%= animal.name %></td>
<td><%= animal.age %> </td>
<% if animal.class == Cat %>
<td><%= animal.meows %> </td>
<% end %>
<% if animal.class == Dog %>
<td><%= animal.barks %> </td>
<td><%= animal.plays_catch %> </td>
<% end %>
</tr>
Then to render #cats = Cat.all:
<%= render partial: "shared/animal", collection: #cats %>
Then to render #dogs = Dog.all:
<%= render partial: "shared/animal", collection: #dogs %>
Obviously it would be overkill to do something like this for this specific example, but the real world project I'm applying it to would not be overkill.
The overall question is: how do you remove nearly identical code that iterates over collections, where the only difference is adding/removing a column of information? It just doesn't feel right to put that logic in the view itself, and leaving the duplication feels wrong.
You could use decorators and add methods that return the extra column(s):
class DogDecorator < Draper::Decorator
def extra_columns
[:barks, plays_catch]
end
end
class CatDecorator < Draper::Decorator
def extra_columns
[:meows]
end
end
...
<% animal.extra_columns.each do |column| %>
<td><%= animal.attributes[column.to_s] %>
<% end %>
...
<% #cats = CatDecorator.decorate_collection(Cat.all)
<%= render partial: "shared/animal", collection: #cats %>
You can use respond_to? to solve the problem more generically. The view logic doesn't feel so wrong when it's more generic.
<% [:meows, :barks, :plays_catch].each do |method| %>
<% if animal.respond_to?(method) %>
<td><%= animal.send(method) %> </td>
<% end %>
<% end %>
You can add a method of the same name to both Cat and Dog classes which would return the specific instance attributes names and values. I'd recommend returning two arrays (one with the names of the fields, other with the fields' values, or vice-versa) since hashes are not exactly ordered. This way you can control the order in which they'll appear in the view.
For example:
#models/cat.rb
def fields_and_attributes
fields = ["Name","Age","Meows"]
attributes = [self.name, self.age]
if self.meows
attributes.push("Yes")
else
attributes.push("No")
end
[fields,attributes] # make sure each attribute is positioned in the same index of its corresponding field
end
#models/dog.rb
def fields_and_attributes
fields = ["Name","Age","Plays catch"]
attributes = [self.name, self.age]
if self.plays_catch
attributes.push("Yes")
else
attributes.push("No")
end
[fields,attributes] # make sure each attribute is positioned in the same index of its corresponding field
end
#controllers/animals_controller.rb
def display_animals
#animals = Cat.all + Dog.all # an array containing the different animals
end
#views/display_animals.html.erb
for i in (0...#animals.size)
fields_and_attributes = #animals[i].fields_and_attributes
for f in (0...fields_and_attributes[0].size)
<p><%= fields_and_attributes[0][f] %> : <%= fields_and_attributes[1][f] %></p>
end
end
Here, we first iterate over all of the animals and call the .fields_and_attributes method of that specific record; we then iterate over the results of calling that method, displaying fields and attributes in the same order as the one defined within the method and also guaranteeing that the code will display every field and every attribute regardless of the difference in the total number of fields for each different animal.
I don't know of any canonical way to accomplish this, but I would use one partial for this in the following way:
<tr>
<% animal.attributes.each do |_, value| %>
<td><%= value %></td>
<% end %>
</tr>
You can get rid of repeated attributes calls by providing in the partial a local variable with pre-obtained model attributes.
EDIT: if you only want to display some attributes.
# Declare whitelist of attributes
# (you can also declare a blacklist and just calculate the difference between two array: all_attributes - blacklist_attributes):
<% whitelist = [:name, :age, :barks] %>
<%= render partial: 'shared/animal',
collection: #dogs,
locals: {attrs: (#dogs.first.attributes.keys.map(&:to_sym) & whitelist)} %>
views/shared/_animal.html.erb:
<tr>
<% attrs.each do |attr| %>
<td><%= animal[attr] %></td>
<% end %>
</tr>
Below is my answer after reviewing posted answers. Basically:
I left the differences within each scaffold model's index page
I made shared partials for common table headers and table data
code below:
#app/views/cats/index.html.erb
<h1>Listing Cats</h1>
<table>
<thead>
<tr>
<%= render partial: "shared/cat_dog_table_headers" %>
<th>Meows</th>
</tr>
</thead>
<tbody>
<% #cats.each do |cat| %>
<tr>
<%= render partial: "shared/cat_dog_table_data", locals: {animal: cat} %>
<td><%= cat.meows %></td>
</tr>
<% end %>
</tbody>
</table>
<br>
<%= link_to 'New Cat', new_cat_path %>
And for the dogs:
#app/views/dogs/index.html.erb
<h1>Listing Dogs</h1>
<table>
<thead>
<tr>
<%= render partial: "shared/cat_dog_table_headers" %>
<th>Barks</th>
<th>Plays catch</th>
</tr>
</thead>
<tbody>
<% #dogs.each do |dog| %>
<tr>
<%= render partial: "shared/cat_dog_table_data", locals: {animal: dog} %>
<td><%= dog.barks %></td>
<td><%= dog.plays_catch %></td>
</tr>
<% end %>
</tbody>
</table>
<br>
<%= link_to 'New Dog', new_dog_path %>
The shared table headers for cats and dogs:
#app/views/shared/_cat_dog_table_headers
<td><%= Name %></td>
<td><%= Age %></td>
The shared table data for cats and dogs:
#app/views/shared/_cat_dog_table_data_headers
<td><%= animal.name %></td>
<td><%= animal.age %></td>

Rails Has Many Forms

I'm having a bit of trouble getting forms for a has_many association to work for a shopping basket. The view is displaying the basket and has a table row for each item. Each row contains a text field so that the user can set the quantity.
The problem is that only the first item row quantity is being passed through in params, even if the second item's quantity has changed too.
Can anyone help please?
Thanks,
Roger
The output of params in the debugger is below, only one line_item is being passed through.
(rdb:2624) e params
{"commit"=>"Recalculate",
"authenticity_token"=>"7TKnhmbBPFiKLzVqTipzH8PDyCrOnKiFixGQ37XDGNY=",
"_method"=>"put", "utf8"=>"✓", "action"=>"update", "id"=>"4",
"line_item"=>{"quantity"=>"3", "id"=>"6"}, "controller"=>"baskets"}
app/controllers/basket_controller.rb
class BasketsController < ApplicationController
def update
begin
#basket = Basket.find(params[:id])
# Can't do anything here yet since the correct parameters aren't being passed through.
rescue ActiveRecord::RecordNotFound
logger.error "..."
end
redirect_to basket_path
end
end
app/views/baskets/show.html.erb
<%= form_for #basket do |f| %>
<table id="items">
<thead>
<tr>
<th>Name</th>
<th>Quantity</th>
<th>Price</th>
<th></th>
</tr>
</thead>
<tbody>
<% #basket.line_items.each do |item| %>
<%= form_for item do |g| %>
<tr class="<%= cycle('alternate', '') %>">
<td><%= item.product.name %></td>
<td>
<span class="decrement-quantity"><b>-</b></span>
<%= g.text_field :quantity %>
<span class="increment-quantity"><b>+</b></span>
</td>
<td class="price"><%= number_to_currency(item.total_price) %></td>
</tr>
<% end %>
<% end %>
<tr class="totals">
<td>Total</td>
<td><%= #basket.total_quantity %></td>
<td class="price"><%= number_to_currency(#basket.total_price) %></td>
<td></td>
</tr>
</tbody>
</table>
<%= f.submit 'Recalculate' %>
<% end %>
You're just creating a new form within the other form. Rails doesn't do anything magical just because you nest one form within another - which is what's causing the issue you're seeing.
The way to handle this situation is to use the fields_for helper and nested_attributes_for - see NestedAttributes for more information too.
I would checkout Railscasts: Complex Forms Part 1. After you watch that, you may be interested in watching Parts 2 & 3.
Ryan Bates covers using fields_for in an understandable and easy to learn fashion.

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