Hi,
I’ve created a Rails application and am having a problem listing by a
particular category in an associated table. I followed the instructions
found at the O’Reilly tutorial
(Radar – O’Reilly) but
have
not had success. Can anyone please outline a better set of instructions
than in the “Showing Recipes in a Category” section? Thank you for your
time!
Melanie
Hey! … I saw that … apparently you are a girl programmer? so am I
… there seems to be so few of us! I just wondered if perhaps you
wanted to be friends?
I’m 28 and live near Chicago, IL. I’ve been a programmer for past 8
years. I’ve been doing PHP post of that time
On 3/3/06, Melanie C. [email protected] wrote:
Melanie
Rails mailing list
[email protected]
http://lists.rubyonrails.org/mailman/listinfo/rails
Hi Nola, and other Railschix (to coin a term),
Are you familiar with the Linuxchix lists? LOTS of girl programmers
there, and in fact girl techies of all sorts. A lot of times, it’s nice
to have a community of female experts. Meaning no offence to anyone
here 
Check them out at
Rachel
Sorry for continuing off topic, but I want to correct a misconception I
inadvertently propagated (say that 5 times fast) plus correct a dumb
typo.
Linuxchix isn’t women only.
Men are welcome on all but one of the 7 or 8 (I forget exactly) lists -
and the women-only one isn’t the heaviest trafficked one by a long shot.
And the real URL is
And Tom, thanks for the welcome! I’ve already gotten some much-needed
assistance here and hopefully will soon be able to contribute as well.
Rachel
PS- Tom, I have lots of thoughts on same-sex institutions, but I’ll keep
that off this list. Feel free to email me directly if you want to have
that conversation
I find it fascinating that for decades (if not millenia!)
women have been striving for a much deserved equality, and
then now that they’re so much closer than they have ever
been to achieving that ideal they perpetuate the grand old
tradition of same sex institutions which have historically
been the ire of their movement in the form of Men’s clubs.
I suppose the difference is that it’s a choice they’ve
made, rather than a choice made for them.
In any case, welcome all Rails and Linux Chixs!
–
– Tom M.
I’ve seen the linuxchix site and recently started a similar thing
… I started a message board at www.devchix.com … if interested,
send me an email.
On 3/4/06, Rachel McConnell [email protected] wrote:
nice to have a community of female experts. Meaning no offence to
Hey! … I saw that … apparently you are a girl programmer? so am I
instructions
Rails mailing list
[email protected]
http://lists.rubyonrails.org/mailman/listinfo/rails
Rails mailing list
[email protected]
http://lists.rubyonrails.org/mailman/listinfo/rails
Rachel
> http://www.linuxchix.org/
I searched for the shop where I could buy the “LinuxChix Wet T-shirt”,
but I couldn’t find it.
(sorry, I couldn’t resist.)
To rant a little, what’s next?
DemocratsRuby.org
RubyForBlacks
or a Debian distribution for GOP, with weakened encryption and mandatory
backdoors?
In forums and mailing lists, nobody cares if you’re ugly, fat or even if
you’re a woman, as long as you are polite and don’t ask stupid
questions?
When I look around me, women are as rare as they are welcome in the IT
techies world. Good code is good code.
I read “why linuxchix exists” but I didn’t get it. It must be this
Mars-Venus thing.
I also checked UbuntuWomen, but I find it even worse.
Alain
Everyone else, I won’t feed the trolls any more, I promise!
But Alain, and anyone who thinks he might just have a point, please do
your research first. Start here:
http://www.tldp.org/HOWTO/Encourage-Women-Linux-HOWTO/
Rachel
As a fellow female programmer I just have to say that David Heinemeier
Hansson is very good looking 
So there goes all my credability as a female programmer.
Melanie C. wrote:
Hi,
I’ve created a Rails application and am having a problem listing by a
particular category in an associated table. I followed the instructions
found at the O’Reilly tutorial
(Radar – O’Reilly) but
have not had success. Can anyone please outline a better set of
instructions than in the “Showing Recipes in a Category” section? Thank
you for your time!
[Just in case this is what you are stuck on, did you miss the <% end %>
required to match the <% if … %> added in recipe/list.rhtml? If that’s
not the answer, read on.]
Assuming everything was still working at the end of page 2, here’s a
breakdown of what is added in “Showing Recipes in a Category”:
The user needs to be able to choose which category to focus on. This
is enabled by turning the category name, displayed in the list, into a
link. It was
and it becomes
<%= link_to recipe.category.name,
:action => “list”,
:category => “#{recipe.category.name}” %>
This is a link to the “list” action in the current controller, and it
also provides a “category” parameter whose value is the name of the
category of the recipe.
[I don’t know why Curt used “#{recipe.category.name}” rather than recipe.category.name - either works for me.]
If you just make this change to the recipe list.rhtml, the list should
still work, the link should show, and when you hover over it (or view
its source in the browser) you should see a URL like
http://127.0.0.1:3000/recipe/list?category=Snacks
…but if you click on it, you should still see the whole list,
because nothing has been done to capture that parameter and use it to
filter the list.
In the RecipeController, the following line is added to the list
method:
@category = @params[‘category’]
This captures the value of the “category” parameter from the HTTP
request, and puts it in the @category instance variable of the
RecipeController instance handling the request. If there is no
“category” parameter - as when you list all recipes - @category will be
nil.
Rails “magically” makes all the controller’s instance variables
available to the view.
The whole of the list method is now:
def list
@category = @params[‘category’]
@recipes = Recipe.find_all
end
When the list action has executed, Rails will (by default) use a
template of the same name (list.rhtml) to render the response.
As well as putting the category name (or nil) in @category, the action
has put an array of all the recipes in @recipes.
If you make this change, everything should still work, but the list will
still show all the recipes.
[In a real application, which might have thousands of recipes, you would
expect the filtering by category to be done in the database query, but
Curt has kept the original Recipe.find_all and put the filtering in the
view.]
[In the year since this article was published there have been many
changes in Rails, and corresponding changes in recommended programming
style. These days you would write:
def list
@category = params[‘category’]
@recipes = Recipe.find(:all)
end
…but the old forms still work, for backwards compatibility.]
<% @recipes.each do |recipe| %>
…
<% end %>
becomes
<% @recipes.each do |recipe| %>
<% if (@category == nil) || (@category == recipe.category.name)%>
…
<% end %>
<% end %>
So a recipe is only displayed as a row in the list if its category name
is the same as @category, or if @category is nil.
Oh - Curt didn’t point out in his description that the <% if … %>
needs a corresponding <% end %> - perhaps that was your problem.
I hope this helps - if not, please tell us more about the symptoms.
Justin
Hi,
Wow, thank you for your explanation! It was very valuable in helping me
find where the problem resides. The application I’ve built has many
listing
pages and multiple controllers and at this point I’m outside the realm
of
the scaffolding. [For example sake, however, I will refer to the
recipes
application.] When I hover over the category I see that the URL has the
category selected, but when it directs to a new page, all of the recipes
are
listed.
At this point, I think I need help in displaying the single category in
a
new listing page since I’m not using the scaffolding. Below are two
examples of this.
[Taken from list2, where it selects the category]
<% @gisrs.each do |gisr| %>
<% if (@employee == nil) || (@employee == gisr.employee.name)%>
[Taken from list3, as stated in the action direction]
<% @gisrs.each do |gisr| %>
It makes sense to me why it’s listing all the “recipes” in list3… I
just
don’t know how to change it! Thanks for your help in this matter - I
appreciate all of your time!
Nola:
http://PhpGirl.blogger.com seems to be down… at least I can’t reach
it…
Aneesha:
Doesn’t DHH have a girl friend or even wife already? 
I’m following the cookbook example on O’Reilly and I’ve managed to show
all the recipes in a specific category via the list?category=Whatever
url.
I was wondering, is it possible to achieve the very same result with a
so-called Pretty URL, like Custom Application Development Software for Business - Salesforce.com or
Custom Application Development Software for Business - Salesforce.com ?
Thanks,
Andre.
Melanie C. wrote:
At this point, I think I need help in displaying the single category in
<% end %>[Taken from list3, as stated in the action direction]
<% @gisrs.each do |gisr| %><%= gisr.employee.name%> <% end %>It makes sense to me why it’s listing all the “recipes” in list3… I
just don’t know how to change it!
Still following the approach in the cookbook tutorial (i.e. filtering in
the view rather than in the query - not the most efficient approach, but
that may not matter if you don’t have too much data or too many
concurrent users) I assume that in the controller, in the list3 action,
you have
@employee = params['employee']
(or
@employee = @params[‘employee’]
if you are still using the old style)
Then the filtering needs to be in list3, rather than list2,
i.e. move the
<% if (@employee == nil) || (@employee == gisr.employee.name)%>
…
<% end %>
into list3.
Does that make sense?
Thanks for your help in this matter -
I appreciate all of your time!
You are welcome
Justin
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