I am using a global array to accumulate controller output as it is added
to the display, eg, when the user adds more items to a list, I add them
to the global.
However, something strange is going on when I then try and use that
global array in a controller method. In a nutshell:
@selected is the array I want to produce (for simplicity, in the example
here it should be identical to $shown). When this runs, the puts
statement output is correct, and .each iterates thru the array.
But debugging with the next line:
@selected.each { |x| puts "XXX:"+x }
@selected is nil; it is not even an Array now! There is output from
WEBrick mentioning an "authenticity_token", altho it doesn't appear to
be an error and I don't know if it is relevent, I have not been using
this for long:
Processing MainController#bysize (for 127.0.0.1 at 2009-05-23 20:36:27)
[POST]
Parameters: {"authenticity_token"=>"5KvBJEMB3I....
I am using a global array to accumulate controller output as it is added
to the display, eg, when the user adds more items to a list, I add them
to the global.
Don't ever do that. Forget that globals exist. They cause problems
with maintainability and (I think) concurrency.
In this case, you should probably be using a local or @instance variable
in the controller.
Don't ever do that. Forget that globals exist. They cause problems
with maintainability and (I think) concurrency.
Yes, that is the CS Doctrine, and generally I agree.
However, it seems dysfunctional to me that it would not be possible (I
promise you will never be asked to maintain my project ;). This could
be some kind of ruby object issue, I am as new to that as I am to rails.
Don't presume that. Just because a language feature exists doesn't mean
it's a good idea to use it.
(Globals have their uses in short scripts. But...really...don't ever
use them in an app of any complexity, or *your* code will be the
dysfunctional part.)
In this case, you should probably be using a local or @instance variable
in the controller.
*There is no way to do that in rails*.
Well, if you're so sure of that, why are you asking for help?
The database I am working with
is not modifiable via the interface (there is no new or create method).
That is irrelevant.
I would use an instance variable (populated by the list method), but
when I call another method referencing this variable, it is no longer
populated:
[...]
Any suggestions?
Do I understand correctly that you'd like to cache a database query in
the controller between requests? If so, perhaps a @@class variable is
the way to go here. Or maybe Rails' built-in caching would do what you
need.
In this case, you should probably be using a local or @instance variable
in the controller.
*There is no way to do that in rails*.
Well, if you're so sure of that, why are you asking for help?
Because, as they say, it is like pulling teeth sometimes
Actually, I didn't really believe that, but after doing a little more
research, I learned that in a production environment a class variable
will not work either, and that it is true:
*YOU CANNOT DO THAT IN RAILS*
ie, you will have to write that data to a file of some sort, and use
some kind of per user key to identify it. Which sucks, but I guess that
is life.
Do I understand correctly that you'd like to cache a database query in
the controller between requests? If so, perhaps a @@class variable is
the way to go here. Or maybe Rails' built-in caching would do what you
need.
Thanks for ringing my head Marnen re: class variables. I only skimmed
thru the pickaxe book on the web last week. My stupidity.
Perhaps this issue has been solved with the "built-in caching"? The
aforementioned "research" was another, similar forum thread from 2006.
Hopefully -- then I will have to admit
I just googled "Ruby on Rails session variable" and found virtually no
info, so I still don't know what this refers to. It does not come up in
the searchable API either, but I imagine they are in there -- can anyone
point me to the spot? Otherwise I will just have to wait for the books
I requested at the library to roll in next week...
