Variables output in views/layouts?

Rails
1

Hi, I usually always deal with arrays this is the first time I have to
deal with a regular variable on a different view in this case in the
layout… so I have in my method:
def online
@online = Status.count_by_sql “SELECT COUNT(*) FROM status
WHERE
status = ‘online’;”
end

and in my layout view I have
<%= @online %>

and nothing comes up… :frowning:

What im doing wrong?

my question is how can I call variables from different controllers on
different views or in my layouts…??

Thanks

2

maybe the count is zero? Have you tried printing the value to the
log? try logger.info(“value of count: #{@count}”) in your controller
code

and if you’re trying to display the number of users online, you might
want to look at the session data to figure this out.

3

Mike G. wrote:

maybe the count is zero? Have you tried printing the value to the
log? try logger.info(“value of count: #{@count}”) in your controller
code

and if you’re trying to display the number of users online, you might
want to look at the session data to figure this out.

Yes I have try this testing it with the view for that method…
and no this is not for the users online but another application.
I also have try it from the console and there works…

so I am puzzle I am searching google with no straight result…
searching for “rails instance variables in layout”

I get a lot of how to use your view variables in layouts and viceversa
but
not the method variables or instance variables

4

if the @online variable contains a value, it will be printed by the
<%= @online %> statement. If nothing is printed, then the variable
contains a null value. What gets printed in your log? Try logging
the value in your view code right before you use the <%= @online %>,
such as the following:

<% logger.info(“online contains #{@online} online.blank?
#{@online.blank?}”) %>
<%= @online %>

if the logger prints out a value for @online, yet the second statement
prints nothing, then something is seriously wrong with your rails
stack

5

Ok I added that and I get:

Rendering pages/show
online contains online.blank? true
Rendered layouts/_menu (0.00793)

it returns true…
I know it has a value because if I go to
http://url.com/status/whos_online
I get the right ammount of users online…
not if I put exacly the same variable in the layout is not showing
anything…

also here is the console:

libre jabber # ./script/console
Loading development environment.

@online = Status.count_by_sql “SELECT COUNT(*) FROM status WHERE
status = ‘online’;”
=> 11
@online
=> 11

so this also works in the view… is obvios that in the layout there is
nothing happening…
do I have to tell the layout from what methong/class is the variable?

Mike G.
escribió:> if the @online variable contains a value, it will be printed by the

stack

so I am puzzle I am searching google with no straight result…

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6

On 5/6/08, rek2 [email protected] wrote:

Ok I added that and I get:

Rendering pages/show
online contains online.blank? true
Rendered layouts/_menu (0.00793)

it returns true…

do you understand that returning true is not what you want? The line
of code I wrote was:

<% logger.info(“online contains #{@online} online.blank?
#{@online.blank?}”) %>

this prints the value of the @online ivar and it also prints whether
or not @online is nil or blank (if it’s an empty string). In this
case it printed “true”, which means that @online doesn’t contain what
you think it contains. Most likely it’s nil.

I know it has a value because if I go to http://url.com/status/whos_online
I get the right ammount of users online…

and what does your whos_online method do?

not if I put exacly the same variable in the layout is not showing
anything…

the @online method will only be assigned in your ‘online’ action. If
you put:

Number of users online: <%= @online %> in your layout, then this will
only contain a value if the action you’re calling assigns to the
@online variable. Since you’re displaying this value in your layout,
you’ll want to globally assign this value either in a before filter in
your controller, or in your ApplicationController.

7

Hmm I’m confused… I though that the application layout will be used if
there is no default layout for
a method, and that instances variables from methods can be used in their
layouts… this is why I was hoping
for this to work.

You are right about the layout. The problem is that the @online is
not being set with every method that uses the application layout. The
purist way to solve the problem would be to create a before_filter in
the ApplicationController and use that filter to load the @online
instance variable. That way it will be inherited by all your
controllers and available to all your actions when they default into
using the application layout.

You might also want to wrap up your lookup into a class method on the
Status controller. It will make things more expressive when you re-
read the code later.

class Status < ARec::Base
…
def self.currently_online
count(:conditions=>{:status=>‘online’})
end
…
end

If you can deal with a little impurity (mixing V/C) in your
application layout you can also put the call to find the count in your
template:

<%= Status.currently_online %>

8

Mike G.
escribió:>

Yes, of course, this is why I sent the console output :slight_smile: so the issue
is that layout is seen the variable as nil.

and what does your whos_online method do?

is the method were I create the variable @online

class StatusController < ApplicationController
def who_online
@online = Status.count_by_sql “SELECT COUNT(*) FROM status WHERE
status = ‘online’;”
end
end

the @online method will only be assigned in your ‘online’ action. If you put:

Number of users online: <%= @online %> in your layout, then this will
only contain a value if the action you’re calling assigns to the
@online variable. Since you’re displaying this value in your layout,
you’ll want to globally assign this value either in a before filter in
your controller, or in your ApplicationController.

Hmm I’m confused… I though that the application layout will be used if
there is no default layout for
a method, and that instances variables from methods can be used in their
layouts… this is why I was hoping
for this to work.

Basically the layout Im using already has data that works well with a
render of _menu etc… I am just trying to add
to a corner of my site the amount of people using the service… so how
will I go to do this? I though this was going to be easy…
:frowning:

Thanks.

9

read the code later.
application layout you can also put the call to find the count in your
template:

Hi, I have ended moving the method to the application controller.
Thanks!

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