Rails - Mar 2006 - Displaying related entries by tags - HELP!

Ok, my site is setup like pretty much every other blog out there.  A 
list of the most recent 5 posts, then by clicking one, you go to an 
individual post page, displaying the full context of that post.

Now, what I would like to do is to display the related entries in the 
side column, which is part of the layout, based on the tags belonging to 
that specific entry.

Here''s my coding so far:

#view
<% for post in @posts %>
  <h2><%= post.title %></h2>

  tags: <%= post.tags.collect { |tag| link_to tag.name, :controller =>
        "articles", :action => "by_category", :category
=> tag.name.to_s
        }.join(", ") %>

  <p><%= post.entry %></p>

<% end %>

#layout
<% for related in @contents_related %>
  <li><%= related.title %><br /></li>
<% end %>

#controller (how do I pass the tag_id and the content_id?)
@contents_related = Content.show_related_entries(?,?)

#model
def self.show_related_entries(t_id, c_id)
    find_by_sql("select c.title from contents c inner join contents_tags 
ct on c.id = ct.content_id where ct.tag_id = #{t_id} and c.id != 
#{c_id}")
  end

The function works if I manually pass a content_id (for my entry) and a 
tag id (for a tag of that entry).  Now, how can I dynamically pull out 
the single content_id for the post, but execute the function for each 
tag related to that individual post???

Hopefully you can see what I''m trying to accomplish, and can have a 
suggestion (even if it''s completely different) as to how I can get this
working!

Thanks for any help!

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

Am Montag, den 13.03.2006, 04:50 +0100 schrieb ryan:
> Ok, my site is setup like pretty much every other blog out there.  A 
> list of the most recent 5 posts, then by clicking one, you go to an 
> individual post page, displaying the full context of that post.
> 
> Now, what I would like to do is to display the related entries in the 
> side column, which is part of the layout, based on the tags belonging to 
> that specific entry.
> 
> Here''s my coding so far:
> 
> #view
> <% for post in @posts %>
>   <h2><%= post.title %></h2>
> 
>   tags: <%= post.tags.collect { |tag| link_to tag.name, :controller
=>
>         "articles", :action => "by_category",
:category => tag.name.to_s
>         }.join(", ") %>
> 
>   <p><%= post.entry %></p>
> 
> <% end %>
> 
> #layout
> <% for related in @contents_related %>
>   <li><%= related.title %><br /></li>
> <% end %>
> 
> #controller (how do I pass the tag_id and the content_id?)
> @contents_related = Content.show_related_entries(?,?)
> 
> #model
> def self.show_related_entries(t_id, c_id)
>     find_by_sql("select c.title from contents c inner join
contents_tags
> ct on c.id = ct.content_id where ct.tag_id = #{t_id} and c.id != 
> #{c_id}")
>   end
> 
> The function works if I manually pass a content_id (for my entry) and a 
> tag id (for a tag of that entry).  Now, how can I dynamically pull out 
> the single content_id for the post, but execute the function for each 
> tag related to that individual post???
> 
> Hopefully you can see what I''m trying to accomplish, and can have
a
> suggestion (even if it''s completely different) as to how I can get
this
> working!
> 
> Thanks for any help!
Hi Ryan,

your message is a little confusing, because of these mass of different
names you use. Names you have in your code or talking about are: post,
tag, entry, category, related, content, related_content,
related_entries, contents_tags

I am not sure what you title content and entry within a blog. What i
would expect is post, comment, tag (or keyword). What are
related_contents and entries? Where is the difference between content
and entry? Maybe you can do a little refactoring.

Please clarify this and try to describe your problem again. If i would
understand it, i probably could help you.

Ciao,
Norman
-- 
Norman Timmler

http://blog.inlet-media.de

Yes, I understand what you mean, it is confusing.  Ok, basically, all I 
want to do is pull a list of related entries which will be displayed in 
the layout in a column to the right, but it must be based on the current 
entry loaded into the view.

I can write a sql query to accomplish this, but I don''t know how to get
the id of the tag (and there will be multiple tags to check, so I need a 
loop?) as well as the id of the post (or entry).

The way I load my posts is with a for loop.  So, in words, I do this in 
the view:

#view
<% for [variable_name] in [@class_variable_holding_the_data] %>
  <% [variable_name].title %>

  #get the tags
  <% [table_name].tags.collect {|tag| tag.name} %>

<% end %>

Now, the @class_variable_holding_the_data, in this case, is one entry 
based on a permalink.  I need to pass that ID along with some sort of 
loop to get all of the tag IDs, and display this in the layout.

I''m still probably confusing you really bad, but maybe you can now see 
what I''m trying to do.  If not, it''s ok, i''m not very
good with
explaining stuff.

Basically, I want to pull related entries in the layout based on any 
number of tags for an individual entry loaded into the view.  If you 
know a better way, I''m open for suggestions.  Thanks!

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

Am Montag, den 13.03.2006, 14:31 +0100 schrieb ryan:
> Yes, I understand what you mean, it is confusing.  Ok, basically, all I 
> want to do is pull a list of related entries which will be displayed in 
> the layout in a column to the right, but it must be based on the current 
> entry loaded into the view.
> 
> I can write a sql query to accomplish this, but I don''t know how
to get
> the id of the tag (and there will be multiple tags to check, so I need a 
> loop?) as well as the id of the post (or entry).
> 
> The way I load my posts is with a for loop.  So, in words, I do this in 
> the view:
> 
> #view
> <% for [variable_name] in [@class_variable_holding_the_data] %>
>   <% [variable_name].title %>
> 
>   #get the tags
>   <% [table_name].tags.collect {|tag| tag.name} %>
> 
> <% end %>
> 
> Now, the @class_variable_holding_the_data, in this case, is one entry 
> based on a permalink.  I need to pass that ID along with some sort of 
> loop to get all of the tag IDs, and display this in the layout.
> 
> I''m still probably confusing you really bad, but maybe you can now
see
> what I''m trying to do.  If not, it''s ok, i''m not
very good with
> explaining stuff.
> 
> Basically, I want to pull related entries in the layout based on any 
> number of tags for an individual entry loaded into the view.  If you 
> know a better way, I''m open for suggestions.  Thanks!
Ok, i try to replay this:

You have a many-to-many association Entry <-> Tag.

Now you want to get all the entries, that share the same tags of a
specific entry, right?

Add a find method to your entry model, that does the magic. Don''t do
this in the view. Another place may be the controller, but for finders
use the model.

class Tag < ActiveRecord::Base
  has_and_belongs_to_many :entries

  def related_entries
    tags.collect { |tag| tag.entries }.flatten.uniq 
  end
end

class Entry < ActiveRecord::Base
  has_and_belongs_to_many :tags
end

Perhaps this solution might be a little bit slow, if you have a lot of
data. Try using this find method:

class Tag < ActiveRecord::Base
  has_and_belongs_to_many :entries

  def related_entries
    tag_ids = tags.collect { |tag| tag.id }
    Entries.find(
      :all,
      :include => tags,
      :conditions => [''tag.id IN (?)'',
tag_ids.join('','')]
    )
  end
end

No matter what way you go, you don''t have to deal with ids:

# view
<% for entry in @entries %>
  <% entry.title %>

  # get the related entries
  <% for related in entry.related_entries %>
    <%= related.title %>
  <% end %>
<% end %>

The perfect way would be to preload the related entries in your
controller and put them into an own instance variable, so if you need
them twice in a view, they are only loaded once.

EntriesController < ApplicationController
 def show
   @entry = Entry.find(params[:id])
   @related_entries = @entry.related_entries
 end
end

This is the best way, if you want the related entries linked in a
sidebar. In your sidebar view just test if the @related_entries is not
nil and then iterate over them and spit out links.

-- 
Norman Timmler

http://blog.inlet-media.de

Yes, that''s exactly what I''m trying to do, and I like your
suggestions
very much.  That was my original intention, but lack of experience let 
me come up with it.  Now, I''m trying to follow what you said to try,
and
I''m getting a "no method" error for
''related_entries''.

Is it possible to use the permalink to get the individual entry instead 
of the id?  Like so:

EntriesController < ApplicationController
 def show
   @entry = Entry.find_by_permalink(params[:permalink])
   @related_entries = @entry.related_entries
 end
end

That''s what I''m trying.  The method
''related_entries'' is defined in the
Tag.rb file, is that what you intended?

You said to add a "find" method in my entry model, but then defined 
''related_entries'' in the tag model.

You obviously know what you''re talking about, but I''m new at
all of
this, so I''m still somewhat confused.

Any suggestions?

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

Am Montag, den 13.03.2006, 18:52 +0100 schrieb ryan:
> Yes, that''s exactly what I''m trying to do, and I like
your suggestions
> very much.  That was my original intention, but lack of experience let 
> me come up with it.  Now, I''m trying to follow what you said to
try, and
> I''m getting a "no method" error for
''related_entries''.
> 
> Is it possible to use the permalink to get the individual entry instead 
> of the id?  Like so:
> 
> EntriesController < ApplicationController
>  def show
>    @entry = Entry.find_by_permalink(params[:permalink])
>    @related_entries = @entry.related_entries
>  end
> end
Sure, the code above should work as expected.
> That''s what I''m trying.  The method
''related_entries'' is defined in the
> Tag.rb file, is that what you intended?
No, the related_entries method should be defined in the Entry model, as
it is finding Entry models. The method is finding related entries, that
share the same tags as the entry, on wich you call the related_entries
method.
> You said to add a "find" method in my entry model, but then
defined
> ''related_entries'' in the tag model.
It is a find method without the find word in the method name ;) Call it
find_related_entries, if you like. It''s just a naming thing. Sorry for
the confusion.
> You obviously know what you''re talking about, but I''m new
at all of
> this, so I''m still somewhat confused.
Hope that helps.
-- 
Norman Timmler

http://blog.inlet-media.de