Would like include model association in to_xml

rubyonrails-talk
1

i have:

class Library << ActiveRecord::Base has_many :books end

class Book << ActiveRecord::Base belongs_to :library end

in my controller i have:

render :xml=> Library.find(:all).to_xml(:include=>books) but, i would like put a condition in the books ( e.: pages >= 100 )

i would like to create a xml with all Libraries, but books with pages more than 100)

How to do this?

2

Just put the conditions in the Library.find call, ie ["books.pages >= ?", 100] or similar. Or better still provide a named scope in Library to do this.

Colin

3

I can`t put the conditionbs in the Library.find, because this relashionship is uses in other part of code. How to call named scope in this case?

4

I can`t put the conditionbs in the Library.find, because this relashionship is uses in other part of code. How to call named scope in this case?

I meant use render :xml=> Library.find(:all, :include => :books, :conditions => ['books.pages >= ?', 100]).to_xml(:include=>books)

Or define a named_scope books_with_more_than_100_pages, though I suspect you would actually parameterise this, then render :xml=> Library.books_with_more_than_100_pages.to_xml(:include=>books)

The above not tested so probably full of typos.

By the way it is generally frowned upon to top post in this list.

Colin

5

but, if me put the conditions in find method, it will filter much libraries ( if libraries has more one book with more than 100 pages ).

6

but, if me put the conditions in find method, it will filter much libraries ( if libraries has more one book with more than 100 pages ).

I don't understand. Your original query would give you everything, the modified one will only give you Libraries and books with greater than 100 pages which is what I thought you asked for. To quote 'i would like to create a xml with all Libraries, but books with pages more than 100'. Perhaps I do not understand exactly what you mean, could you give a more detailed example of what you want?

Colin

7

i want to list every libraries, but only show the your books with more than 100 pages.

8

i want to list every libraries, but only show the your books with more than 100 pages.

I understand now. I can not immediately see how to do that in one query. Anyone else?

You are _still_ top posting. It makes it much more difficult for someone who has not been following the thread to pick it up and help.

Colin

9

I run into these sort of to_xml problems all the time. Especially with nested models it gets really ugly, but I think for you just adding a line to your model should fix it.

...I've been working on an issue similar to this is on another thread but its a little more complicated because it uses order and a join, but your situation is similar.

http://groups.google.com/group/rubyonrails-talk/browse_thread/thread/82d640d37bdfb3cb?hl=en

Here is how I would solve your issue.

Add this line to your model

class Library << ActiveRecord::Base      has_many :books      has_many :long_books, :class_name => "Book", :conditions => 'pages > 100' end

Now update the controller to include :long_books Library.find(:all, :include => :long_books).to_xml (:include=>:long_books)