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 = Array.new
$shown.each { |thing| puts "->#{thing}<-"; @selected.push thing;
}
@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....
Anyone know why, and if there is a work around?
--
Posted via http://www.ruby-forum.com/.
Mk 27 wrote:> 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. Best, -- Marnen Laibow-Koser http://www.marnen.org marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org -- Posted via http://www.ruby-forum.com/.
Marnen Laibow-Koser wrote:> 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. After all, if globals were *that* bad, I presume $global a syntax for them should not exist either? -- Posted via http://www.ruby-forum.com/.
Marnen Laibow-Koser wrote:> 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*. The database I am working with is not modifiable via the interface (there is no new or create method). 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: class SomeController def list @array = Some.find(:all) end def another_method [don''t bother referring to @array, it is empty] end end Since there are actually a variety of methods here that could have been responsible for the last @array, I cannot simply repeat the block in list and hope that @array will be what is it currently is/was when last applied in a view. Any suggestions? -- Posted via http://www.ruby-forum.com/.
Mk 27 wrote: [...]> After all, if globals were *that* bad, I presume > > $global > > a syntax for them should not exist either?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.) Best, -- Marnen Laibow-Koser http://www.marnen.org marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org -- Posted via http://www.ruby-forum.com/.
Mk 27 wrote:> Marnen Laibow-Koser wrote: > >> 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. Best, -- Marnen Laibow-Koser http://www.marnen.org marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org -- Posted via http://www.ruby-forum.com/.
Marnen Laibow-Koser wrote:> Mk 27 wrote: >> Marnen Laibow-Koser wrote: >> >>> 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 *YOU CAN DO THAT IN RAILS* So thanks again -- MK -- Posted via http://www.ruby-forum.com/.
On May 24, 8:18 am, Mk 27 <rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:> 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. >Not to be snarky, but this seems to describe a session variable perfectly... --Matt Jones
Matt Jones wrote:> > Not to be snarky, but this seems to describe a session variable > perfectly... > > --Matt JonesWell thanks Matt for waiting until I had spent the afternoon re-writing my code to use instance variables (just kidding). Actually, having no professional web dev experience, it occurred to me that maybe this is what cookies would be good for*. At any rate, I was probably jumping the gun a little (or getting derailed, haha) in my ambitions for learning project #1. 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... thanks again and in advance, MK *Page caching is definitely not the thing. I need to keep track of what has happened on the page -- ie, all the relevant data is there in front of the user. KEY QUESTION: Where would I start if I wanted to grab and parse the "raw" page in it''s current state? I was also thinking I could keep a hidden form, but the former (parse the page) would be preferable if possible. -- Posted via http://www.ruby-forum.com/.
On May 24, 10:11 pm, Mk 27 <rails-mailing-l...-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:> 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...see the Session section at http://api.rubyonrails.org/classes/ActionController/Base.html Fred> > thanks again and in advance, MK > > *Page caching is definitely not the thing. I need to keep track of what > has happened on the page -- ie, all the relevant data is there in front > of the user. KEY QUESTION: Where would I start if I wanted to grab and > parse the "raw" page in it''s current state? > > I was also thinking I could keep a hidden form, but the former (parse > the page) would be preferable if possible. > -- > Posted viahttp://www.ruby-forum.com/.
Matt Jones wrote:> > Not to be snarky, but this seems to describe a session variable > perfectly... > > --Matt JonesYep, that''s exactly what I wanted, the equivalent of a global hash. Evidently this is implemented with cookies. Long live snarky! Thanks Fred too for the reference. -- Posted via http://www.ruby-forum.com/.