Rails - Apr 2005 - Views: dealing with criss-crossing commonalities?

In my views I have to dimensions of commonality: Views related to one 
controller have in common the kind of object they''re about. More 
importantly, to me, is the commonality among views pertaining to the 
same action on different kinds of objects. That is, I''d like to have 
all list, edit, show, ... views respectively to have the same basic 
layout. Can this be done with little effort -- POLS-like?

Michael

-- 
Michael Schuerig                            You can twist perceptions
mailto:michael-q5aiKMLteq4b1SvskN2V4Q@public.gmane.org                       
Reality won''t budge
http://www.schuerig.de/michael/               --Rush, Show Don''t Tell

On Apr 22, 2005, at 12:09 PM, Michael Schuerig wrote:
> In my views I have to dimensions of commonality: Views related to one
> controller have in common the kind of object they''re about. More
> importantly, to me, is the commonality among views pertaining to the
> same action on different kinds of objects. That is, I''d like to
have
> all list, edit, show, ... views respectively to have the same basic
> layout. Can this be done with little effort -- POLS-like?
Look at Layouts and Partials.

For Layouts you''ll have to create your instance variables with the same
name (e.g. @item instead of @user or @post) so that the data comes out 
the same way.

For Partials you can pass them in.

Another way is to use helper methods.

Following is a helper method from my app/helpers/application_helper.rb 
file that I created for spitting out columns of a record in a table. (I 
use this on my list pages.)

First, in action:
<%= create_table_from @roles, :edit => ''role/edit'',
:delete =>
''role/delete'' %>

Produces:
<table class="sortable autolinkrows
highlightrows"><thead><tr>
<th comparemethod="number">Id</th>
<th comparemethod="text">Name</th>
<th></th><th></th></tr></thead><tbody>
<tr><td>2</td><td>Admin
Helpers</td><td><a
href="/role/edit/2">[edit]</a></td><td><a 
href="/role/delete/2">[delete]</a></td></tr>
<tr><td>1</td><td>Admins</td><td><a 
href="/role/edit/1">[edit]</a></td><td><a 
href="/role/delete/1">[delete]</a></td></tr>
<tr><td>3</td><td>Franchise
Owners</td><td><a
href="/role/edit/3">[edit]</a></td><td><a 
href="/role/delete/3">[delete]</a></td></tr>
<tr><td>5</td><td>Job</td><td><a 
href="/role/edit/5">[edit]</a></td><td><a 
href="/role/delete/5">[delete]</a></td></tr>
<tr><td>4</td><td>Restaurant
Owners</td><td><a
href="/role/edit/4">[edit]</a></td><td><a 
href="/role/delete/4">[delete]</a></td></tr>
<tr><td>6</td><td>Super-Admin</td><td><a 
href="/role/edit/6">[edit]</a></td><td><a 
href="/role/delete/6">[delete]</a></td></tr>
</tbody></table>


While this:
<%= create_table_from @users, :edit => ''edit'', :delete
=> ''delete'',
:columns => [ ''id'', ''login'',
''email'' ] %>

Produces:
<table class="sortable autolinkrows
highlightrows"><thead><tr>
<th comparemethod="number">Id</th>
<th comparemethod="text">Login</th>
<th comparemethod="text">Email</th>
<th></th><th></th></tr></thead><tbody>
<tr><td>1</td><td>phrogz</td><td>gavin-XtLdkLkwz3ZWk0Htik3J/w@public.gmane.org</td><td><a
href="/user/edit/1">[edit]</a></td><td><a 
href="/user/delete/1">[delete]</a></td></tr>
</tbody></table>


The code:
   # _rows_ ::An array of model instances, such as returned by 
ActiveRecord::Base#find_all
   # _options_ ::(optional) A hash with one or more of the key/value 
pairs:
   # ToDo - document :columns, :edit, and :delete options
   #
   # Returns the HTML string of a table for all the records in the 
_rows_ array, with the
   # ability to sort by columns, and (if supplied) with links to edit or 
delete them
   def create_table_from( rows, options={} )
     return ''<p class="ancillary">no rows
found</p>'' unless rows.first

     model = rows.first.class
     columns_by_name = model.columns_hash
     #Map ActiveRecord Column types to TableSort.js sort types
     sort_types = Hash.new(''text'')
     sort_types[:integer] = sort_types[:float] = ''number''
     sort_types[:datetime] = sort_types[:date] = ''date''
     sort_types[:timestamp] = sort_types[:time] = ''time''

     html = ''<table class="sortable autolinkrows
highlightrows">''
     col_names = options[:columns] || options[''columns'']
     if col_names
       #find the Column objects for each name
       columns = col_names.collect do |col_name|
         columns_by_name[ col_name ]
       end
     else
       columns = model.columns
     end

     #ToDo: deal with columns that are methods and not actual columns

     #draw the table header
     html << "<thead><tr>\r"
     columns.each do |column|
       sort_type = column ? sort_types[ column.type ] : sort_types[ 
:text ]
       nice_name = column ? column.name.humanize : ''foo''
       html << %Q|<th comparemethod="#{ sort_type }">#{
nice_name
}</th>\r|
     end
     html << ''<th></th>'' if options[ :edit ]
     html << ''<th></th>'' if options[ :delete
]
     html << "</tr></thead><tbody>\r"

     rows.each do |row|
       html << "<tr>"
       columns.each do |column|
         html << %Q|<td>#{ row.send( column.name ) }</td>|
       end
       if options[:edit]
         dest_pair = options[:edit].split(''/'')
         dest_action = dest_pair.last
         dest_controller = ( dest_pair.length > 1 ) ? dest_pair.first : 
@controller.controller_name
         html << "<td>#{ link_to ''[edit]'',
:controller=>dest_controller,
:action=>dest_action, :id=>row.id }</td>"
       end
       if options[:delete]
         dest_pair = options[:delete].split(''/'')
         dest_action = dest_pair.last
         dest_controller = dest_pair.length > 1 ? dest_pair.first : 
@controller.controller_name
         html << "<td>#{ link_to ''[delete]'', 
:controller=>dest_controller, :action=>dest_action, :id=>row.id
}</td>"
       end
       html << "</tr>\r"
     end
     html << ''</tbody></table>''
   end

On Saturday 23 April 2005 03:14, Gavin Kistner wrote:
> On Apr 22, 2005, at 12:09 PM, Michael Schuerig wrote:
> > In my views I have to dimensions of commonality: Views related to
> > one controller have in common the kind of object they''re
about.
> > More importantly, to me, is the commonality among views pertaining
> > to the same action on different kinds of objects. That is,
I''d like
> > to have all list, edit, show, ... views respectively to have the
> > same basic layout. Can this be done with little effort --
> > POLS-like?
>
> Look at Layouts and Partials.
I''m already using both of them in addition to helper methods.
> For Layouts you''ll have to create your instance variables with the
> same name (e.g. @item instead of @user or @post) so that the data
> comes out the same way.
>
> For Partials you can pass them in.
Both of these still require some effort to keep different views for the
same object as well as same view kinds for different objects
consistent. I was hoping for a way to get consistency more or less
automatically. The noteworthy thing about layouts that affords this 
consistency is the inversion of control (now is that a fashionable 
concept?), where a structure is defined in a single place and imposed 
on all other places where it is used.

This is hardly a pressing problem for me, currently, more an aesthetic 
thing...

Michael

-- 
Michael Schuerig                       Face reality and stare it down
mailto:michael-q5aiKMLteq4b1SvskN2V4Q@public.gmane.org        --Jethro Tull,
Silver River Turning
http://www.schuerig.de/michael/