thr3ads.net - Rails - restful polymorphic [Jan 2007]

If this information is useful, please help other people find it:
Share via:

Carl Johnson

2007-Jan-14 08:17 UTC

restful polymorphic

In working on a RESTful website, I''ve encountered a stumbling block
involving polymorphic associations.

For example, given:

map.resources :posts do |post|
   post.resources :comments, :name_prefix => ''post_''
end
map.resources :photos do |photo|
   photo.resources :comments, :name_prefix => ''photo_''
end

Where comments is polymorphic. The acts_as_commentable plugin fits the
bill.

So we have routes like:

/posts/678/comments
/photos/185/comments

If we want to create a new comment for photo 678 we would send a POST to
/posts/678/comments. Nice and RESTful.

But... how do I generate the path for the form target if the comment
form is in a shared partial (DRY)?

I did find one post about this on Rails Weenie and the answer was more
of a workaround... an ugly helper that uses link_to. Is there any way to
do this gracefully, such as *_path?

Ideally:

<% form_for(comment_path(@photo)) %>

...would be smart enough to determine the object type of @photo and
generate the correct /photos/@photo.id/comments route automatically.

Any thoughts? Anyone run into this, and if so how did you solve it?

Thanks!

-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Roderick van Domburg

2007-Jan-16 18:21 UTC

head link

Re: restful polymorphic

Funny, moments before you posted this I was struggling with the exact 
same thing *and* was looking at the exact same Techno Weenie article.

I opted to go with a modified version of the before_filter approach like 
so. Read below for my observations.

  # POST /comments
  # POST /comments.xml
  def create
    @comment = Comment.new(params[:comment])

    @commentable = find_commentable
    @commentable.comments << @comment

    respond_to do |format|
      if @comment.save
        flash[:notice] = ''Comment was successfully created.''
        format.html { eval("redirect_to 
#{@commentable.class.to_s.underscore}_url(@commentable)") }
        format.js # render create.rjs; update comment listing
        format.xml { head :created, :location => 
eval("#{@commentable.class.to_s.underscore}_url(@commentable)") }
      else
        format.html { render :controller => 
@commentable.class.to_s.underscore, :id => @commentable.id, :action => 
:show }
        format.js { :render :js => @comment.errors.to_json } # XXX
        format.xml { render :xml => @comment.errors.to_xml }
      end
    end
  end

  private

  def find_commentable
    # lazy regex, just finds instances of /controller/id
    sections =
request.env[''REQUEST_URI''].scan(%r{/(\w+)/(\d*)})

    sections.map! do |controller_name, id|
      [controller_name.singularize.camelize, id]
    end

    klass, id = sections.pop
    eval("#{klass}.find(id)")
  end

I''ve got the entire thing working brilliantly as long as it''s
a Ajaxed
or if the non-Ajax submission is valid. What I haven''t figured out yet 
to do properly is handle invalid non-Ajax submissions and still populate 
the input fields.

I see two possible paths:

1. Perform a redirection after doing some session storage. Implement a 
before_filter that checks for session-stored form submissions and 
errors.

2. Move all views that are commentable into partials.

Though #2 is "kinda OK", it remains a bit of a stretch.
Interested to hear your thoughts and any code improvements.

- Roderick

-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Carl Johnson

2007-Jan-16 21:24 UTC

head link

Re: restful polymorphic

I''m glad I''m not the only one struggling with this problem!
Frankly, I''m
a bit surprised Rails 1.2 is going to be released with open questions 
like this.

How are you generating your form destinations in your comment form(s)?

-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Roderick van Domburg

2007-Jan-16 22:18 UTC

head link

Re: restful polymorphic

Carl Johnson wrote:> How are you generating your form destinations in your comment form(s)?
Here''s what I have, let me know if you work up something better.

In news_items/show.rhtml:

  <%= render :partial => ''shared/comment_form'', :locals
=> {
:commentable => @news_item } %>

shared/_comment_form.rhtml:

  <div id="comment_form">
    <h2>New comment</h2>

    <%= error_messages_for :comment %>

    <% remote_form_for(:comment, :url => comments_path(commentable)) do 
|f| -%>
      <p>
        <label for="body">Comment</label><br />
        <%= f.text_area :body %>
      </p>

      <p>
        <%= submit_tag ''Create'' %>
      </p>
    <% end -%>
  </div>

-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Carl Johnson

2007-Jan-16 22:38 UTC

head link

Re: restful polymorphic

>     <% remote_form_for(:comment, :url => comments_path(commentable))
do
> |f| -%>
I am not able to simply use comments_path because I have overlapping 
routes. Like this:

map.resources :pictures do |picture|
  picture.resources :comments, :name_prefix => ''picture_''

map.resources :posts do |post|
  post.resources :comments, :name_prefix => ''post_''

So in order for my New Comment form to POST to the correct URL I have to 
use either picture_comments_path or post_comments_path. In the routing 
above the name_prefixes are required, otherwise one overwrites the 
other.

It seems like your solution will work for you as long as you have only 
one parent defined in the routing for comments, but as soon as you want 
to add comments for something like :blog_items, comments_path is not 
going to know what to do. Unless I''m missing something?

Carl

-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Roderick van Domburg

2007-Jan-16 23:19 UTC

head link

Re: restful polymorphic

Carl Johnson wrote:> It seems like your solution will work for you as long as you have only 
> one parent defined in the routing for comments, but as soon as you want 
> to add comments for something like :blog_items, comments_path is not 
> going to know what to do. Unless I''m missing something?
You are right. I hadn''t tackled that issue yet. However, it should be 
solvable by something (untested and hand-coded) like:

pictures/show.rhtml:

  <%= render :partial => ''shared/comment_form'', :locals
=> {
:commentable => @picture, :name_prefix => ''picture_'' }
%>

shared/_comment_form.rhtml:

  <% eval("remote_form_for(:comment, :url => 
#{name_prefix}comments_path(commentable))") do
|f| -%>

-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Carl Johnson

2007-Jan-16 23:43 UTC

head link

Re: restful polymorphic

> You are right. I hadn''t tackled that issue yet. However, it should
be
> solvable by something (untested and hand-coded) like:
> 
> pictures/show.rhtml:
> 
>   <%= render :partial => ''shared/comment_form'',
:locals => {
> :commentable => @picture, :name_prefix =>
''picture_'' } %>
Yeah that''s pretty simple. I''ll probably do the same too...
been putting
off converting my comment submission to RESTful so far.

I still think that the _path generators should be able to do a little 
magic and determine the correct route for polymorphic targets. Hopefully 
that will eventually be built-in. I will try to tackle it myself in the 
Rails code but it will take me quite a while, if ever! :)

-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Carl Johnson

2007-Jan-17 07:47 UTC

head link

Re: restful polymorphic

Roderick van Domburg wrote:
> You are right. I hadn''t tackled that issue yet. However, it should
be
> solvable by something (untested and hand-coded) like:
> 
> pictures/show.rhtml:
> 
>   <%= render :partial => ''shared/comment_form'',
:locals => {
> :commentable => @picture, :name_prefix =>
''picture_'' } %>
> 
> shared/_comment_form.rhtml:
> 
>   <% eval("remote_form_for(:comment, :url => 
> #{name_prefix}comments_path(commentable))") do
> |f| -%>
FYI, this inspired me to convert to RESTful comment submissions and 
here''s what I did. I tried to limit what I pass to each partial since I
already have to pass a bunch of pagination stuff.

show.rhtml:

<%= render(:partial => ''shared/comments'', :locals =>
{:comment_pages =>
@comment_pages, :count => @comment_count, :item => @picture})%>

shared/_comments.rhtml:

<% form_for(:comment, :url => 
eval("#{item.class.to_s.downcase}_comments_path(#{item.id})")) do |f|
%>

-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Chris Wanstrath

2007-Jan-17 10:09 UTC

head link

Re: restful polymorphic

On 1/16/07, Carl Johnson
<rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:
> <% form_for(:comment, :url =>
> eval("#{item.class.to_s.downcase}_comments_path(#{item.id})")) do
|f| %>
We do a lot of polymorphic stuff like this where I work.  Just a suggestion:

instead of
eval("#{item.class.to_s.downcase}_comments_path(#{item.id})")

try
send("#{item.class.to_s.downcase}_comments_path", item.id))

Or, wrap it up:
def polymorphic_comments_path(item)
  send("#{item.class.to_s.underscore}_comments_path", item))
end

If you find yourself using eval, there''s usually another way to do it
in Ruby.

-- 
Chris Wanstrath
http://errtheblog.com

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Claudio Poli

2007-Feb-10 04:05 UTC

head link

Re: restful polymorphic

hi,
so far, so good, I''m having the same problems.

say now I can create Comment for an Article, rendering comment form 
partial directly from /app/views/articles/show.rhtml

<%= render(:partial => ''shared/comment_form'', :locals
=> {:item =>
@article, :name_prefix => ''article_''})%>

#/app/views/shared/_comment_form.rhtml
<%= error_messages_for :comment %>

<% form_for(:comment, :url => polymorphic_comments_path(item)) do |f|
%>
<dl>
  <dt class="required">Title<br /><small>Please be
concise.</small></dt>
  <dd><%= f.text_field ''title'' %></dd>
  <dt class="required">Comment<br /><small>Write
your comment
here.</small></dt>
  <dd><%= f.text_area ''comment'', :class =>
''articleintroduction'' %></dd>
</dl>
<p>
  <%= submit_tag "Create" %>
</p>
<% end %>

this form will generate
<form action="/articles/1/comments" method="post">

which works well.

# routes.rb
 map.resources :articles do |post|
    post.resources :comments, :name_prefix => ''article_''
 end

all done.
# controller using simply_commentable
  # POST /comments
  # POST /comments.xml
  def create
    @commentable = find_commentable
    @comment = @commentable.comment_by!(current_user,params[:comment] )
    respond_to do |format|
      if @comment.save
        flash[:notice] = ''Comment was successfully created.''
        format.html { eval("redirect_to 
#{@commentable.class.to_s.underscore}_url(@commentable)") }
        format.js # render create.rjs; update comment listing
        format.xml { head :created, :location => 
eval("#{@commentable.class.to_s.underscore}_url(@commentable)") }
      else
        format.html { render :controller => 
@commentable.class.to_s.underscore, :id => @commentable.id, :action => 
:show }
        format.js { render :js => @comment.errors.to_json } # to check
        format.xml { render :xml => @comment.errors.to_xml }
      end
    end
  end

  private
  def find_commentable
     sections =
request.env[''REQUEST_URI''].scan(%r{/(\w+)/(\d*)})
     sections.map! do |controller_name, id|
       [controller_name.singularize.camelize, id]
     end
     klass, id = sections.pop
     eval("#{klass}.find(id)")
   end

as suggested. I''m posting the entire thing just for reference to other 
users.
anyway a question arises, say I want to edit a comment, we should use 
the controller Comments, how is the link_to built? with which routes and 
params? what should we put in the views/partials?

thanks

-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Adam Roth

2007-Feb-15 23:49 UTC

head link

Re: restful polymorphic

Have you made any progress on this? I''ve been searching for the same
answers.

Claudio Poli wrote:> hi,
> so far, so good, I''m having the same problems.
> 
> say now I can create Comment for an Article, rendering comment form 
> partial directly from /app/views/articles/show.rhtml
> 
> ...snip...
> 
> as suggested. I''m posting the entire thing just for reference to
other
> users.
> anyway a question arises, say I want to edit a comment, we should use 
> the controller Comments, how is the link_to built? with which routes and 
> params? what should we put in the views/partials?
> 
> thanks
-- 
Posted via http://www.ruby-forum.com/.

--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en
-~----------~----~----~----~------~----~------~--~---

Rails - Jan 2007 - restful polymorphic

restful polymorphic

Re: restful polymorphic

Re: restful polymorphic

Re: restful polymorphic

Re: restful polymorphic

Re: restful polymorphic

Re: restful polymorphic

Re: restful polymorphic

Re: restful polymorphic

Re: restful polymorphic

Re: restful polymorphic