Rails - Feb 2005 - Passing id around

Fellow rail workers,

Quick intro. ;) Hi I dig ruby and am now getting into rails. I''ve
been working on a simple little blog app using rails just to get my
bearings and all.

The simplified DB schema:

CREATE TABLE posts (
	id serial PRIMARY KEY,
	title varchar(255),
	content text
);

CREATE TABLE comments (
	id serial PRIMARY KEY,
	post_id integer NOT NULL REFERENCES posts ON DELETE CASCADE,
	content text
);

My current endeavor is adding comments to user posts.

You''ll see that "post_id" may not be null; I want every
comment to
correspond to an existing post.

When creating a new comment I''ll need to pass the post id along with
it.

For viewing a post and its comment I have a
"app/views/post/show.rhtml"
file with a link to leave a comment.

<%= link_to "Leave a comment.", :controller =>
"comment",
  :action => "new", :params => { "post_id" =>
@post.id } %>

And with that I can pick up the post id in the comment controller like
so:

def new
	Comment.new
	Comment.post_id = @params[''post_id'']
end

It works, but it''s not very pretty with urls like
/comment/new?post_id=2

I know there must be a better (rails) way to do this. One perhaps being:

	flash["post_id"] = @post.id

What I had in mind was perhaps the following based on the scaffolding
code. Using the follwing link:

<%= link_to "Leave a comment.", :controller =>
"comment",
  :action => "create", ...

def create
	# create the comment with the correct post id
	# and redirect directly to editing it. 
end

I guess my question is this: How is the create action from the
scaffolding code normally used. :)

Thanks in advance.

Emiel
-- 
Emiel van de Laar

Hi Emiel,

On 12.2.2005, at 22:43, Emiel van de Laar wrote:
>
> And with that I can pick up the post id in the comment controller like
> so:
>
> def new
> 	Comment.new
> 	Comment.post_id = @params[''post_id'']
> end
Here''s an alternative, maybe a bit more OO way for that:

@comment = Comment.new(@params["comment"])
@post = Post.find(@params["post_id"])

@post.comments << @comment
>
> It works, but it''s not very pretty with urls like 
> /comment/new?post_id=2
Well, do you think this would be prettier:
> <%= link_to "Leave a comment.", :controller =>
"comment",
>   :action => "create", :id => @post.id %>
Then the url would be /comment/create/2

Anyway, I wouldn''t sweat too much about that comment creation url.
It''s
not like anyone would link to it or that google would need to index it.
>
> I know there must be a better (rails) way to do this. One perhaps 
> being:
>
> 	flash["post_id"] = @post.id
Nah, that''s abusing the flash method. I would strongly suggest relaying
the id in the query vars (or in the url as above), that''s always the 
safest bet.

//jarkko
>
> What I had in mind was perhaps the following based on the scaffolding
> code. Using the follwing link:
>
> <%= link_to "Leave a comment.", :controller =>
"comment",
>   :action => "create", ...
>
> def create
> 	# create the comment with the correct post id
> 	# and redirect directly to editing it.
> end
Why would you want to create it before the user has written anything? 
You''d probably end up with a lot of bogus items in your comments. Just 
make a comment form page (or put the form in your post view page) and 
point the form to your create method. You can sneak the post_id in in a 
hidden form variable.

//jarkko



--
Jarkko Laine
http://jlaine.net
http://odesign.fi


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