Guys,
I''m working to get my head around REST. Reading the chapter in AWDROR
is not helping unfortunately, but I think it may be a result of either
an error in my copy of the book, or my understanding in general.
REST in Rails for simple examples is easy to follow, but it''s where
associations come into the mix that I get a bit confused.
Take the example in the AWDROR book. You have ArticlesController and
CommentsController, and the appropriate nested resource mapping to
make comments available via articles urls...so that you can do:
/articles/1/comments
and get a list of comments for the article with id 1. So far, so good.
Now, extend this example hypothetically and say that I, for whatever
reason, want to get all comments, irregardless of article. One would
expect that, if #index is used for all listings of comments, then I''d
have to write CommentsController#index as:
def index
if params[:article_id]
@comments = Article.find(params[:article_id]).comments
else
@comments = Comment.find(:all)
end
respond_to do |format|
format.html # index.rhtml
format.xml { render :xml => @articles.to_xml }
end
end
This would allow the method to be used in two contexts...one where I''m
after
/articles/1/comments
and one where I''m seeking just
/comments
Now, this design could get pretty nasty, I''d presume, because
let''s
say I have other resources in my application that could also have
comments. I''m suddenly forced to walk through the parameters for each
method that could be called in this way and change the behavior of the
resource accordingly.
Here''s where I think an error in the book is confusing me. Of course,
it may not be an error at all. In the table on page 418, it lists
actions that are called in response to various url mappings.
The first listed in CommentsController says that
Actions in CommentsController
GET /articles/1/comments index
comments_url(:article_id => 1)
This says that /articles/1/comments will call #index in the
CommentsController, but if you''ll note in the actual implementation of
the CommentsController, there is no index defined!?!
Which leads me to believe that this is wrong, and that #index will
only ever be called when accessed directly via a GET to /comments
So, two questions:
1. Is this actually incorrect on the part of the book? Is #index
unnecessary when called in the context of a nested resource?
2. How does one manage a resource controller implemention of a
resource that might be shared amongst different parent resources
(i.e., I have three resources: Articles, BlogEntries, and
ProductListings, all that have a has_many :comments?
Thanks for any help you can provide in cleaning up these mental cobwebs.
John
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That''s confusing, isn''t it? Its kinda up to you how you want it to work. Does it make sense to get a comment outside of the article scope? To me, it does not, so I wouldn''t even worry about that case. In fact, I''d make sure that there was no route that could even pull that URL up. Other cases, like /users/1/groups or /groups would make sense. In that case, you would definitely need to code for both. The thing to remember is that it''s about resources and URLs. What does your application require you to do? There''s no "right way" or "wrong way" for this particular case. On Nov 26, 2007 1:57 PM, John Wells <lists-y8WhZ5XeQqVfbyii3fMa5/Z4XP/Yx64J@public.gmane.org> wrote:> > Guys, > > I''m working to get my head around REST. Reading the chapter in AWDROR > is not helping unfortunately, but I think it may be a result of either > an error in my copy of the book, or my understanding in general. > > REST in Rails for simple examples is easy to follow, but it''s where > associations come into the mix that I get a bit confused. > > Take the example in the AWDROR book. You have ArticlesController and > CommentsController, and the appropriate nested resource mapping to > make comments available via articles urls...so that you can do: > > /articles/1/comments > > and get a list of comments for the article with id 1. So far, so good. > > Now, extend this example hypothetically and say that I, for whatever > reason, want to get all comments, irregardless of article. One would > expect that, if #index is used for all listings of comments, then I''d > have to write CommentsController#index as: > > def index > if params[:article_id] > @comments = Article.find(params[:article_id]).comments > else > @comments = Comment.find(:all) > end > respond_to do |format| > format.html # index.rhtml > format.xml { render :xml => @articles.to_xml } > end > end > > This would allow the method to be used in two contexts...one where I''m > after > /articles/1/comments > and one where I''m seeking just > /comments > > Now, this design could get pretty nasty, I''d presume, because let''s > say I have other resources in my application that could also have > comments. I''m suddenly forced to walk through the parameters for each > method that could be called in this way and change the behavior of the > resource accordingly. > > Here''s where I think an error in the book is confusing me. Of course, > it may not be an error at all. In the table on page 418, it lists > actions that are called in response to various url mappings. > > The first listed in CommentsController says that > Actions in CommentsController > GET /articles/1/comments index > comments_url(:article_id => 1) > > This says that /articles/1/comments will call #index in the > CommentsController, but if you''ll note in the actual implementation of > the CommentsController, there is no index defined!?! > > Which leads me to believe that this is wrong, and that #index will > only ever be called when accessed directly via a GET to /comments > > So, two questions: > > 1. Is this actually incorrect on the part of the book? Is #index > unnecessary when called in the context of a nested resource? > 2. How does one manage a resource controller implemention of a > resource that might be shared amongst different parent resources > (i.e., I have three resources: Articles, BlogEntries, and > ProductListings, all that have a has_many :comments? > > Thanks for any help you can provide in cleaning up these mental cobwebs. > > John > > > >--~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
On 11/26/07, Brian Hogan <bphogan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> Its kinda up to you how you want it to work. Does it make sense to get a > comment outside of the article scope? To me, it does not, so I wouldn''t even > worry about that case. In fact, I''d make sure that there was no route that > could even pull that URL up.Yeah, bad example, but it''s in a book just about everyone on this list has. So assume it *does* make sense to use comments outside of the context of Articles.> Other cases, like /users/1/groups or /groups would make sense. In that> case, you would definitely need to code for both.> > The thing to remember is that it''s about resources and URLs. What does your > application require you to do? There''s no "right way" or "wrong way" for > this particular case.So in the case of my example of Articles, BlogEntries, and ProductListings sharing comments, I''d have to do: def index if params[:article_id] @comments = Article.find(params[:article_id]).comments elseif params[:blog_entry_id] @comments = BlogEntry.find(params[:blog_entry_id]).comments elseif params[:product_listing_id] @comments = ProductListing.find(params[:product_listing_id]).comments end respond_to do |format| format.html # index.rhtml format.xml { render :xml => @comments.to_xml } end end And the above assumes that CommentsController#index will indeed be called in response to /articles/1/comments, which the book seems to contradict itself on. For example, another confusing passage: "We''ll create a CommentsController to manage the comments resource. We''ll give it the same actions as the scaffold-generated articles controller, except we''ll omit index and show, because comments are displayed only from an article''s show action." (p 419) Thanks for your continued help. John --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
You''re on the right track. Keep going. Go with what your gut tells you with this stuff. Does it make sense? Absolutely it does. You''re polymorphically showing the comments for an article, a blog_entry, etc. What you pass in the URL will determine what record it looks up. The way you''re doing it is nice and clean too because you access it via the scoped entity as opposed to doing comment.find_by_id. You''ll need logic similar to this for doing a show, and maybe even a new / create.. Probably not for an edit, but then again, maybe. I suggest a before_filter for that to reduce code duplication. On Nov 26, 2007 2:32 PM, John Wells <lists-y8WhZ5XeQqVfbyii3fMa5/Z4XP/Yx64J@public.gmane.org> wrote:> > On 11/26/07, Brian Hogan <bphogan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > Its kinda up to you how you want it to work. Does it make sense to get a > > comment outside of the article scope? To me, it does not, so I wouldn''t > even > > worry about that case. In fact, I''d make sure that there was no route > that > > could even pull that URL up. > > Yeah, bad example, but it''s in a book just about everyone on this list > has. So assume it *does* make sense to use comments outside of the > context of Articles. > > > Other cases, like /users/1/groups or /groups would make sense. In > that > > case, you would definitely need to code for both. > > > > The thing to remember is that it''s about resources and URLs. What does > your > > application require you to do? There''s no "right way" or "wrong way" for > > this particular case. > > So in the case of my example of Articles, BlogEntries, and > ProductListings sharing comments, I''d have to do: > > def index > if params[:article_id] > @comments = Article.find(params[:article_id]).comments > elseif params[:blog_entry_id] > @comments = BlogEntry.find(params[:blog_entry_id]).comments > elseif params[:product_listing_id] > @comments = ProductListing.find(params[:product_listing_id]).comments > end > respond_to do |format| > format.html # index.rhtml > format.xml { render :xml => @comments.to_xml } > end > end > > And the above assumes that CommentsController#index will indeed be > called in response to /articles/1/comments, which the book seems to > contradict itself on. For example, another confusing passage: > > "We''ll create a CommentsController to manage the comments resource. > We''ll give it the same actions as the scaffold-generated articles > controller, except we''ll omit index and show, because comments are > displayed only from an article''s show action." (p 419) > > Thanks for your continued help. > > John > > > >--~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
On 11/26/07, Brian Hogan <bphogan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> You''re on the right track. Keep going. Go with what your gut tells you with > this stuff. Does it make sense? Absolutely it does.So you''re saying the CommentsController#index would indeed be called in response to /articles/1/comments? If so, then why do they specifically not implement this in the book example? Thanks, John --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
I don''t know what the book is suggesting you do. The index action refers to the return of a collection. If you have a nested route, /articles/1/comments would look for comments#index. On Nov 26, 2007 3:17 PM, John Wells <lists-y8WhZ5XeQqVfbyii3fMa5/Z4XP/Yx64J@public.gmane.org> wrote:> > On 11/26/07, Brian Hogan <bphogan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > You''re on the right track. Keep going. Go with what your gut tells you > with > > this stuff. Does it make sense? Absolutely it does. > > So you''re saying the CommentsController#index would indeed be called > in response to /articles/1/comments? If so, then why do they > specifically not implement this in the book example? > > Thanks, > John > > > >--~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
Brian, the issue with polymorphic resources has been experienced by others (I have not had to deal with this yet). If you are just starting out in RESTful design, then I''m not sure if this will be of help, but since you are asking the right questions it might be. James Golick has developed a plugin called ResourceController. Part of this responsibility is to solve the issue you raised. See the section "Polymorphic Resources". http://jamesgolick.com/2007/10/19/introducing-resource_controller-focus-on-what-makes-your-controller-special HTH, Nicholas On Nov 26, 4:27 pm, "Brian Hogan" <bpho...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> I don''t know what the book is suggesting you do. > > The index action refers to the return of a collection. If you have a nested > route, /articles/1/comments would look for comments#index. > > On Nov 26, 2007 3:17 PM, John Wells <li...-y8WhZ5XeQqVfbyii3fMa5/Z4XP/Yx64J@public.gmane.org> wrote: > > > > > On 11/26/07, Brian Hogan <bpho...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > You''re on the right track. Keep going. Go with what your gut tells you > > with > > > this stuff. Does it make sense? Absolutely it does. > > > So you''re saying the CommentsController#index would indeed be called > > in response to /articles/1/comments? If so, then why do they > > specifically not implement this in the book example? > > > Thanks, > > John--~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
@Nicholas: I think you meant to direct this to the OP. On Nov 27, 2007 7:06 AM, Nicholas Henry <nicholas.henry-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> > Brian, the issue with polymorphic resources has been experienced by > others (I have not had to deal with this yet). If you are just > starting out in RESTful design, then I''m not sure if this will be of > help, but since you are asking the right questions it might be. James > Golick has developed a plugin called ResourceController. Part of this > responsibility is to solve the issue you raised. See the section > "Polymorphic Resources". > > > http://jamesgolick.com/2007/10/19/introducing-resource_controller-focus-on-what-makes-your-controller-special > > HTH, > Nicholas > > On Nov 26, 4:27 pm, "Brian Hogan" <bpho...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > I don''t know what the book is suggesting you do. > > > > The index action refers to the return of a collection. If you have a > nested > > route, /articles/1/comments would look for comments#index. > > > > On Nov 26, 2007 3:17 PM, John Wells <li...-y8WhZ5XeQqVfbyii3fMa5/Z4XP/Yx64J@public.gmane.org> wrote: > > > > > > > > > On 11/26/07, Brian Hogan <bpho...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > > You''re on the right track. Keep going. Go with what your gut tells > you > > > with > > > > this stuff. Does it make sense? Absolutely it does. > > > > > So you''re saying the CommentsController#index would indeed be called > > > in response to /articles/1/comments? If so, then why do they > > > specifically not implement this in the book example? > > > > > Thanks, > > > John > > >--~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
Quite right, Brian, sorry about that - yes my post was directed to John. On Nov 27, 9:12 am, "Brian Hogan" <bpho...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> @Nicholas: > > I think you meant to direct this to the OP. > > On Nov 27, 2007 7:06 AM, Nicholas Henry <nicholas.he...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > > > Brian, the issue with polymorphic resources has been experienced by > > others (I have not had to deal with this yet). If you are just > > starting out in RESTful design, then I''m not sure if this will be of > > help, but since you are asking the right questions it might be. James > > Golick has developed a plugin called ResourceController. Part of this > > responsibility is to solve the issue you raised. See the section > > "Polymorphic Resources". > > >http://jamesgolick.com/2007/10/19/introducing-resource_controller-foc... > > > HTH, > > Nicholas > > > On Nov 26, 4:27 pm, "Brian Hogan" <bpho...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > I don''t know what the book is suggesting you do. > > > > The index action refers to the return of a collection. If you have a > > nested > > > route, /articles/1/comments would look for comments#index. > > > > On Nov 26, 2007 3:17 PM, John Wells <li...-y8WhZ5XeQqVfbyii3fMa5/Z4XP/Yx64J@public.gmane.org> wrote: > > > > > On 11/26/07, Brian Hogan <bpho...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote: > > > > > You''re on the right track. Keep going. Go with what your gut tells > > you > > > > with > > > > > this stuff. Does it make sense? Absolutely it does. > > > > > So you''re saying the CommentsController#index would indeed be called > > > > in response to /articles/1/comments? If so, then why do they > > > > specifically not implement this in the book example? > > > > > Thanks, > > > > John--~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
On 11/27/07, Nicholas Henry <nicholas.henry-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> > Quite right, Brian, sorry about that - yes my post was directed to > John.Very interesting...thanks Nicholas! --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---