Rails - Mar 2006 - How to go DRY?

We are creating a website for creating and maintaining communities. When
members of a community are listed, we show their summary in a TABLE. So
we have written a _member.rhtml partial to show this summary for that
member. To show the memberlist we do
render :partial => member, :collection => @members

Now the problem is the row displayed for every member by the _member
partial, may differ depending on the context. For instance, if we are
listing them under a community, we want to show a BLOCK button next to
each member, to allow the user to block other members from that
community. When displaying members in a general list, not under a
community, we want to show an INVITE button against every member to add
him as a friend in the user''s Friends list.
There are a number of other cases, wherein the buttons or additional
info shown for each member is different depending on the context.

In such cases how do we code the _member partial to take care of all
different possible ways to show a member?
In general is there a guideline on how to make sure we Don''t Repeat
Ourselves?

-Yash

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

On 3/22/06, Yash <yash@persistent.co.in> wrote:
> Now the problem is the row displayed for every member by the _member
> partial, may differ depending on the context. For instance, if we are
> listing them under a community, we want to show a BLOCK button next to
> each member, to allow the user to block other members from that
> community. When displaying members in a general list, not under a
> community, we want to show an INVITE button against every member to add
> him as a friend in the user''s Friends list.
> There are a number of other cases, wherein the buttons or additional
> info shown for each member is different depending on the context.
>
> In such cases how do we code the _member partial to take care of all
> different possible ways to show a member?
> In general is there a guideline on how to make sure we Don''t
Repeat
> Ourselves?
You could parameterize the partial and use calls like this:

render :partial => member, :collection => @members, :locals => {
:invite => true }

Then you would conditionally show or hide parts of the partial based
on the parameters:

<tr>
<!-- other fields -->
<% if invite %><td><!-- invite button --></td><% end
%>
<% if block %><td><!-- block button --></td><% end
%>
</tr>

I have old code which did this, and I received errors about nil
variables for when :invite was not passed, but this may have been
addressed, and is also generally easy to prevent: <% if
defined?(invite) and invite %> to default to off, and <% if
!defined?(invite) or invite %> to default to on.

I hope this helps, and that I didn''t make any mistakes in my samples.
:P
> -Yash
Sincerely,

Tom Lieber
http://AllTom.com/
http://GadgetLife.org/