Why is rails running a partial twice? - ruby-on-rails

I am calling a partial in one of my views like so:
<%= render :partial => 'events/attendees', :collection => #attendees %>
the partial however is running twice for some reason...here is the partial:
<% #attendees.each do |user| %>
<li><%= link_to user.name, user %></li>
<% end %>
and i verified that rails is in fact running this partial twice because the output shows each item from #attendees twice

That's because one "loop" is from Rails (:collection means that Rails will render the partial for each item in the collection, in this case #attendees) and one loop via your own partial.
Change the partial to below (not sure about the relation between attendee/user, but here is a sample):
<li><%= link_to attendee.name, attendee.user %></li>
Or, change the call of the partial to:
<%= render :partial => 'events/attendees' %>

Related

Passing in variable to rails partial

Right now I have a rails partial that looks like this:
<%= render :partial => "/talk/partials/comment", :collection => #comments, :locals => {:votes => #votes} %>
I am passing in a collection of comments and another local variable.
That comment partial then goes right into using the comment variable and works fine.
I have since made another partial called '/talk/partials/comment_2014'. When I try this, I am getting the error undefined local variable or method 'comment'. From what I can gather, when I have a different partial name, something with the variable also changes. I would like to keep the same comment variable for the new partial ''/talk/partials/comment_2014'. How would I go about doing this?
Something I tried which did not work was the following:
<% #comments.each do |comment| %>
<%= render :partial => "/talk/partials/comment_2014", comment: comment, :locals => {:votes => #votes} %>
<% end %>
which did not work either.
You can do it this way
<% #comments.each do |comment| %>
<%= render "/talk/partials/comment_2014", comment: comment, votes: #votes %>
<% end %>
Or
<% #comments.each do |comment| %>
<%= render partial: "/talk/partials/comment_2014", locals: { comment: comment, votes: #votes } %>
<% end %>
Notice in the second way the comment is inside the locals.

Rails: how to communicate view controller in AJAX?

The case is when user click an add link, if the url already added, there will be a alert otherwise will display a form to add new bookmark. The code below works quite well for checking the duplicated url, but if the url is not duplicated I just don't know how to render a add bookmark (in this case the page will be loaded like a normal non ajax request)
This is the link in view
<%= link_to "add", user_bookmark_add_path(current_user, bookmark), remote: true %>
The link will invoke the controller action add
# controllers/bookmarks_controller.rb
def add
#bookmark = Bookmark.find(params[:bookmark_id])
respond_to do |format|
format.js
end
end
The javascript file
# views/bookmarks/add.js.erb
<% if duplicated_url? #bookmark.url %>
alert("Duplicated")
<% else %>
# how to render the new bookmark form here
<% end %>
Any suggestion ? Thanks
Create a partial for new bookmark form.
_form.html.erb
<%= form_for(bookmark) do |f| %>
<%= f.text_field :name %>
<%= f.submit "submit" %>
<% end %>
Add id to your link
.html.erb
<%= link_to "add", user_bookmark_add_path(current_user, bookmark), remote: true, id: "bookmark" %>
Replace your link with partial.
.js.erb
<% if duplicated_url? #bookmark.url %>
alert("Duplicated")
<% else %>
$("#bookmark").replaceWith("<%= j render "form", bookmark: Bookmark.new %>");
<% end %>
On your add.js.erb file, in the else part of the code you can append a partial to your list like this:
$('#your_list').append(
"<%= escape_javascript(render('your_item_of_the_table_partial')) %>"
);
This partial can be a list item, a table row, a div with your content, anything. The thing is, you will need a chunk of html to be re-rendered on your screen with the new content.
Example of a list item partial:
# _bookmark_item.html.erb
<li><%= #bookmark.url %> </li>
Try something like this:
$('#your_div_id').append('<%= escape_javascript(raw render :partial => 'your_form_partial') %>')
This will add the contents of your ruby partial to the DOM.

ruby on rails render deosn't find the file

I'm new to ruby on rails.
In views/events I have "_form.html.erb" which is rendered in "new.html.erb" by this code:
<%= render "form" %>
Now I want to render "_form.html.erb" in "index.html.erb" which is in the same folder(views/events).
But I get the error "missing template".
I guess I have to add some thing to controller, please help me to render form in other pages of views...
You "usually" don't render a form in an index action. Most form partials are setup semantically to expect a #my_resource, but if you're doing everything the rails way you're not going to have a instance variable during your index action. There's a number of ways you can do this but this is probably the quickest.
You probably have some collection (let's pretend you're using books) in your index action:
#views/books/index.html.erb
<% #books.each do |book| %>
...
<%= render "form" %>
...
<% end %>
You can just set an instance variable somewhere prior to rendering the form:
#views/books/index.html.erb
<% #books.each do |book| %>
<% #book = book %>
...
<%= render "form" %>
...
<% end %>
Another way to do it would be through passing in some locals to a partial. You'd have to change all of your references in _form to use a local variable instead. Then you can call render like this:
<%= render :partial => "form", :locals => {:book => book } %>
You can try
<%= render "events/form" %>
I had this problem before and this solved

Rails: Link to partials?

At the moment I try to do following:
I created several partials (i.e. _show_signature.html.erb) for my user.
Now I want to show them on clicking a link.
In my user controller, I created a new action:
def show_signature
#is_on_show_signature = true
end
def show_information
#is_on_show_information = true
end
on my user show.html.erb i coded this:
<% if #is_on_show_information %>
<%= render :partial => 'show_information' %>
<% elsif #is_on_show_signature %>
<%= render :partial => 'show_signature' %>
<% end %>
and in my "navigationbar" i wrote:
<ul>
<li class="profile-tab">
<%= link_to 'Information', show_information_path %>
</li>
<li class="profile-tab">
<%= link_to 'Signature', show_signature_path %>
</li>
</ul>
In my routes.rb I wrote:
map.show_information '/user-information', :controller => 'user', :action => 'show_information'
map.show_signature '/user-signature', :controller => 'user', :action => 'show_signature'
now my problem:
clicking on my "information" link will redirect me to http://localhost:3000/user-information (cause I told him this path in routes.rb - I think) and I get an error:
uninitialized constant UserController
But that's not what I want... My user show path is something like:
http://localhost:3000/users/2-loginname
(by coding
def to_param
"#{id}-#{login.downcase.gsub(/[^[:alnum:]]/,'-')}".gsub(/-{2,}/,'-')
end
in my user model)
I want to link to somethink like http://localhost:3000/users/2-test/user-information.
Any ideas how it will work? Any ideas why I get this error?
As far as Rails conventions go, the model itself is singular (User) but the table (users) and controller (UsersController) are both pluralized. This can cause a significant amount of confusion at first, and even after years of working with Rails I still make the mistake of trying things like 'user = Users.first' which is, of course, not valid, as often you get to thinking about table names instead of class names.
Also, for toggling the display of elements on a page, you probably want to use the link_to_remote method which uses AJAX for updates instead of a page refresh. If you're okay with a full page refresh, those actions will need to redirect_to something, such as the page referrer, or you will get a blank page or error since the page template does not exist.
Typically what you do is:
<ul>
<li class="profile-tab">
<%= link_to_remote 'Information', show_information_path %>
</li>
<li class="profile-tab">
<%= link_to_remote 'Signature', show_signature_path %>
</li>
</ul>
Then each action is as you have specified, however, the page template show_information.rjs would look like:
page.replace_html('extra_information', :partial => 'show_information')
Keep in mind you will need to have a placeholder to receive the partial contents, so simply wrap your optional sections in an element with a specific ID:
<div id="extra_information">
<% if #is_on_show_information %>
<%= render :partial => 'show_information' %>
<% elsif #is_on_show_signature %>
<%= render :partial => 'show_signature' %>
<% end %>
</div>

ruby-on-rails: rendering partials on each item in a list

I have the following in a view (.html.erb) :
<% #posts = GetAllPostsFunctions %> (removed for berivity)
<% #posts.each do |post| %>
<%= post.title %>
<%= render :partial => "posts/post_show" %>
<% end %>
the posts_show partial has the following:
....
<td><%=h #post.title %> </td>
But I get the following error
You have a nil object when you didn't expect it!
The error occurred while evaluating nil.title
Any ideas?
You can also simply things by using the :collection for render :partial. Which pass each item in the value for :collection to a local variable sharing the name of your partial.
<% #posts = GetAllPostsFunctions %> (removed for berivity)
<%= render :partial => "posts/post_show", :collection => #posts %>
In this case, Rails will render post_show for each item in #posts with the local variable post_show set to the current item. It also provides handy counter methods.
Successfully using this approach would require renaming the app/views/posts/_post_show.html.erb partial to app/views/posts/_post.html.erb to or changing every occurance of post in your partial to post_show. If you renamed the partial to the conventional _post.html.erb which will then allow you to simply do:
<%= render :partial => #posts %>
Which will render the partial for every single post in the #posts variable.
Since the post variable in the each loop is a locale variable you have to make it available to the partial:
<%= render :partial => "posts/post_show", :locals => {:post => post} %>
You can then access the title through the local variable post:
<td><%=h post.title %> </td>
You could also simplify the whole thing by rendering the posts as collection. Take a look at the Rails documentation for more information:
http://api.rubyonrails.org/classes/ActionController/Base.html#M000658
It doesn't look like you're setting the #post of the partial, so when it goes to evaluate the partial it gets a null reference.
Alternately, ensure that your post fetching functions are actually returning something
I'm not positive, but I think in the partial you have to do post.title not #post.title
Sorry if I misunderstood you, I'm new to rails.

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