Hey guys, I'm having trouble understanding a Rails construct. I'm using Rails 3 but I doubt this is specific to this version.
I have a model, Goal that has_many :commits and naturally, a Commit model that belongs_to :goal. I created the proper migration so that commits_table.references :goal.
I am actually going through the Rails Getting Started guide, except in that article they use a Post and Comment respectively.
Now that I've described the situation I can express my confusion. On the Goal's show view, I have embedded a form to create a new Commit which is 'attached' to the currently viewed Goal. This works fine and all. However, I am having trouble understanding why we do this
<%= form_for([#goal, #goal.commits.build]) do |f| %>
Shouldn't it be form_for(#commit)? I understand why we want the #goal, to provide some context since the commit is a nested resource. However, in the actual generated source, the form is appropriately named as commit, that is, the fields are named commit_blah. How did Rails know this? I understand that there's this whole system of "trust and magic" and all, but I mean at least at the high level, what from this code hinted to Rails that I wanted a commit?
I looked at the documentation for form_for and it seems like one of the parameters could be the action to take for the form. I imagine that in this case, that's what the #goal.commits.build parameter is for? To designate the action to take? Is this how Rails deduces that I want a commit? Would this also explain why this form is handled by the Commit controller even though this code is in the Goal's view?
Also, why are these parameters passed as an array ([])? In Ruby, will the method still just take it as two separate parameters, or is there a reason why this was passed this way?
Finally, rails generate automatically gave me some error showing code in my other _form.html.erb partials:
<% if #commit.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#commit.errors.count, "error") %> prohibited this commit from being saved:</h2>
<ul>
<% #commit.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
If I want to add this to this embedded form, how would I do so? I guess my question is, what would I use in place of #commit?
Thanks. I'm just trying to get my head around these new concepts.
If you go back to the documentation and click 'show source', you'll see
def form_for(record_or_name_or_array, *args, &proc)
...
case record_or_name_or_array
when String, Symbol
...
when Array
object = record_or_name_or_array.last
object_name = options[:as] || ActiveModel::Naming.singular(object)
apply_form_for_options!(record_or_name_or_array, options)
args.unshift object
else
...
end
...
output << fields_for(object_name, *(args << options), &proc)
...
For form_for, the first parameter can be a record, name or an array. In your case, you pass it an array. The code then determines the 'object' as the last member of that array, which is your #goal.commits.build object. The object name is determined from the ActiveModel::Naming.singular method.
console > ActiveModel::Naming.singular(#goal.commits.build)
=> "commit"
Then it generated the appropriate form fields using fields_for and 'commit'.
It looks like you are using nested resources. Check your routes.rb file to see if you have something like:
map.resources :commits, :has_many => :goals
or perhaps:
map.resources :commits do |commit|
commit.resources :goals
end
If that is the case, then you will need to supply both the commit and goal objects to the form_for method.
Related
I'm trying to render simple check_boxes in a list of results so users can select on which of these results to get additional content for.
Example model setup (names changed):
UserRequest has_one :response
Response has_many :individual_results
IndividualResult has_one :contact_info
In the UserRequestsController I have a show action, which shows the user_request (duh), response, and its individual_results in a table.
The user should be able to select items (= contact_info) to request additional content for those. For some reason I don't manage to render the check_boxes after days of trying. Basically, I don't really understand where and how to store the array of selected contact_infos and how to pass it to the method that then gets the additional content.
My attempt was:
Create a ContactInfosController (didn't exist before, the user was only creating and showing her requests up to now, so contact_info was "model only" before)
Create a method request_content(contact_infos) (as post, to pass the user-selected contact_infos to. If I were to make it Restful, it would probably be "edit/update")
Add the form with check_boxes search_request#show
My search_request/show.html.erb:
<tbody>
<% if #response %>
<% form_for #contact_infos, url: contact_infos_request_content_path(#contact_infos) do |form| %>
<% #response.individual_results.each do |result| %>
# result.foo, ...
# result.contact_info.bar
<%= form.check_box "contact_info", "contact_info.request_content?", "true", "false %>
<% end %>
# form.submit
<% end %>
<% end %>
</tbody>
As it didn't work, I also had to declare the instance variable #contact_infos in RequestsController#show as #contact_infos = #response.individual_results.map { |r| r.contact_info }
Now, it fails at the check_box with "undefined method `merge'". Also, not sure how the params would be passed? I feel I went seriously "off the rails" and probably screwed up the design with this as it seems way too complicated...
Would anybody be so kind and help me get into the right direction, e.g., how would you pass the response to a method to request additional information? Read tons online but somehow couldn't apply it.
Thanks so much!
I'm pretty new to rails and I'd like to set my links for a certain page dynamically. I have a table called "Unfinished" and it has a column called "link" (corrected from "links") I'd like to be able to call the "link" record in the view to set my link_to link path.
I am trying to do this...
<%= link_to #unfinished.link(:p => #post.id) do %> FINISH <% end %>
...but that's not working.
my controller says:
def show
#post = Post.find(params[:id])
#unfinished = Unfinished.where('progress = ?', #post.progress).last
end
and the controller logic works fine...until I try to put the #unfinished.link into link_to
Edit:
Error Message:
wrong number of arguments (1 for 0)
Model
class Unfinished < ActiveRecord::Base
end
The type of links are :
step1_path
step2_path
step3_path
I am making a multipage form that you can save partway through. Based on a value in the #post.progress column (like 1, 2, 3) the correct path to complete the post will be provided (step1_path, step2_path etc...)
try this.
<%= link_to eval(#unfinished.link.to_s) do %> FINISH <% end %>
since the link you want is actually a named route, so you will need to eval it.
but with this you wouldn't be able to be able to pass in the post id, which you will need.
If the route is the same for all records (save for what part you are on based on the progress attribute) do you even need to store it in the database? You could just make the link method return the path (that you would still need to eval).
something like
def link (post)
"step#{self.progress}_path(post.id)"
end
and then eval the link on the way back. but Not sure if that will work, just thinking out loud...
There are gems that do multi-stage forms perhaps looking into them might help?
I have a form where I'd like to create a parent record and a child record at the same time. For a simple example let's say its a Company with the first Employee.
in my controller I do something like:
def new
#company = Company.new
#company.employees.new
end
and in my view this:
<%= form_for(#company) do |form| %>
<div>
<%= form.label :name %>
<%= form.text_field :name %>
</div>
<%= form.fields_for :employees do |employee_form| %>
<div>
<%= employee_form.label :name %>
<%= employee_form.text_field :name %>
</div>
<% end %>
<% end %>
and back in my controller again:
def create
#company = Company.new(params[:company])
#company.employees << Employee.new(params[:company][:employees_attributes]["0"])
# save stuff
end
Question 1:
I couldn't get the employee collection on the company to be populated with the single employee created in the form. When I looked at the params I found the [:employees_attributes]["0"] stuff.
What I have works, but is there a cleaner way to do this?
Question 2:
If the validation doesn't pass for the employee I get a generic "Employees is invalid" instead of the Name required validator message. I get I am calling save on the collection and rails is doing its best to bubble a validation error up, but is there a cleaner way to do this so I can get the errors specific to the employee?
In Short
How can I clean this up so the related models are created automatically from the params, and so that I get the validation messages for a single employee.
Thanks for looking.
1) fields_for arranges for the child objects attributes to be nested inside the parent objects attributes in the params hash that gets sent back to the controller action. To get Rails to automatically update the child objects tell the parent model to accept nested attributes using the accepts_nested_attributes_for declaration.
2) There is an errors object for every ActiveRecord object. Loop through the errors list and display the messages.
Best way to achieve this is to create a partial and a view helper method that will take render the errors for you. then replace the generated errors messages in the forms with a call to your render_error_messages method. You have all the code to do this already in the generated forms. You just need to refactor that code into a partial, create the helper - which should accept an array of model names as a parameter then do what you want with the info. Wither render a partial for each model or render a partial that will deal with child objects as well as the parent object. Totally your call.
3) Change your new action to build rather that create a new child object so instead of
def new
#company = Company.new
#company.employees.new
end
do this
def new
#company = Company.new
#company.employees.build
end
4) Watch those Railscasts to see how accepts_nested_attributes works
http://railscasts.com/episodes/196-nested-model-form-part-1
and
http://railscasts.com/episodes/197-nested-model-form-part-2
Update
So how does the above information leave you in relation to your questions.
1) What I have works, but is there a cleaner way to do this?
You've fixed the new action as per point 3 above right? Now your create action can look like this
def create
#company = Company.new(params[:company])
# save stuff
end
Which is much cleaner as it has reverted to the original generated create action.
You may not think that's much of an update and therefore not that much cleaner. Well in isolation you'd be right. But consider that you could add as many relationships as you like ad add as many fields_for declarations as you like nd you could turn the user -> employee relationship into a has_many (I know that you wouldn't). You could do all that and your create and update actions stay EXACTLY the same and that's why it's cleaner.
2) is there a cleaner way to do this so I can get the errors specific to the employee?
Given my response in point 2 above you know that there is an errors object on the employee object as well as on the user object right? You also know now that you can loop through that errors object to get the messages right?
So you could do this
<% if #user.employee.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#user.employee.errors.count, "error") %> prohibited this user from being saved:</h2>
<ul>
<% #user.employee.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
At the risk of repeating myself I'll just say that you should refactor your error messages view code into a partial that will take any object as a parameter then you can call it from any view thus enabling you to change the styling and the functionality for all your forms.
Hope that's clearer
In my Rails CREATE controller for a model, if the name of the record already exists, via JS I'm outputting the following response:
<%=#space.errors%>
Which outputs:
permissionsis invalidnameThis project name is already in use
In the model I have:
validates_uniqueness_of :name :message => 'This project name is already in use'
How do I get rid of the noise: "permissionsis invalidname" for the life of me I can't find it in the docs? Apologies if I'm missing something hugely obvious.
The issue is that you are actually returning the array containing all the error objects.
What you actually want is:
<ul>
<% #space.errors.full_messages.each do |msg| %>
<li><%=h msg %></li>
<% end %>
</ul>
This will give you a list of the errors.
I'm also pretty sure there's a nicer way to do this (i.e. some sort of helper built in to rails), but I haven't been able to find it in the docs for rails 3.
I have the following code in a layout:
Posted <%=time_ago_in_words post.created_at %> ago
<% if post.has_tag != nil %>
in the <%= post.get_first_tag.name %> category
<% end %>
And the following code in the post model which is inheriting form ActiveRecord::Base
def has_tag
!self.tags.empty?
end
def get_first_tag
self.tags[0]
end
Tags is also inherited from ActiveRecord::Base and Post 'has_many' Tags
Firstly: Is this the best way of checking if the post object has at least 1 associate tag attribute.
Secondly: Should I be putting this logic into a helper method?
Thirdly: Why doesn't the following work (it returns a # where the tags should be):
in the <%= post.tags.to_sentence %> category,
I guess its because tags aren't actually stored as an array attribute, but i don't really know.
This is a perfectly good way of checking if there are tags or not. However, self.tags.empty? will return true or false so post.has_tag will never be nil.
It's worth noting that, in ruby, it is common to name methods that return true or false with a question mark. So post.has_tag? would be a better name for your method (like the empty? method for the tags).
This sort of method belongs in the model class rather than a helper as it is not specific to the view layer; you might want to call this method from other model classes, for example.
The reason you are getting # instead of your tag names is that you are trying to convert a collection of tags to a sentence and you need instead to convert the names of the tags to a sentence. You should be able to do
post.tags.map(&:name).to_sentence
which will take the names of the tags and turn them into a sentence.
For one thing, you probably need
<% if post.has_tag %>
instead of
<% if post.has_tag != nil %>
In your definition, has_tag should never return nil, and thus 'in the...' part will always be shown.
Generally, your idea seems fine to me: I often add helpers like these to models.