Summary of problem: my params hash is being made nil in my controller
without any reason that I can identify.
Everything was fine until I put this new code as the first lines of code
in my controller. But the block is not being executed because the puts
statement is not evaluated:
def calculate
if params[:id]
puts "in if statement"
@query = Query.where(:id => params[:id])
params = eval(@query[0].queryString).to_options
params[:query_end_date].to_options!
params[:query_start_date].to_options!
end
The controller then fails in the first line of the next block of code
(below), and the error is that I am evaluating a nil object.
if params[:entity_selection]=="ELB"
@instances_array = get_instances_array(params[:instance])
@grouped_elb_instances get_grouped_elb_instances(@instances_array,
params[:instance])
else
@instances_array = []
@grouped_elb_instances = []
end
If I comment out the first ''if'' block, the controller works
perfectly.
When I print the params before the if statement, it has a value, but for
some reason, it seems like the params variable is cleared from memory.
I have no idea what is happening.
Any ideas?
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On 15 September 2011 22:42, Jonathan S. <lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:> Any ideas?Are you *sure* the "if" is not getting run through? Change the "puts" to a "raise"... -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On Thu, Sep 15, 2011 at 17:42, Jonathan S. <lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:> But the block is not being executed because the puts > statement is not evaluated: > > def calculate > > if params[:id] > puts "in if statement"Where are you looking for the output of the puts? On the web page? In the log? On the screen of the server? In too many faces? ;-) -Dave -- LOOKING FOR WORK, preferably Ruby on Rails, in NoVa/DC; see main web site. Main Web Site: davearonson.com Programming Blog: codosaur.us Excellence Blog: dare2xl.com -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
@Michael: I''ll give this a shot soon and let you know what happens. @Dave: I was looking for the output on the screen of the server. Should I look somewhere else? I''d have to post the entire controller to show you this, but when I included my begin-rescue-ensure block (with the criminal if statement at the top of the begin block), the error still happens, but not until the ensure block..even though the params hash is referenced multiple times before then. I can post the whole controller if that would be helpful, but in any case, I''ll see what happens with a raise statement in the criminal if. Let me know if you have any other suggestions. JS Michael Pavling wrote in post #1022225:> On 15 September 2011 22:42, Jonathan S. <lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote: >> Any ideas? > > Are you *sure* the "if" is not getting run through? Change the "puts" > to a "raise"...-- Posted via http://www.ruby-forum.com/. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On Sep 15, 10:42 pm, "Jonathan S." <li...-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:> Summary of problem: my params hash is being made nil in my controller > without any reason that I can identify. > > Everything was fine until I put this new code as the first lines of code > in my controller. But the block is not being executed because the puts > statement is not evaluated: > > def calculate > > if params[:id] > puts "in if statement" > @query = Query.where(:id => params[:id]) > params = eval(@query[0].queryString).to_options > params[:query_end_date].to_options! > params[:query_start_date].to_options! > end >Local variables are tricky - merely mentioning them causes them to spring into existence. For example if you run if false x = 2 end Then the local variable x is created, with value nil. I think the same thing is happening here - a local variable called params is being created, which is shadowing the params instance method. Fred> The controller then fails in the first line of the next block of code > (below), and the error is that I am evaluating a nil object. > > if params[:entity_selection]=="ELB" > @instances_array = get_instances_array(params[:instance]) > @grouped_elb_instances > get_grouped_elb_instances(@instances_array, params[:instance]) > else > @instances_array = [] > @grouped_elb_instances = [] > end > > If I comment out the first ''if'' block, the controller works perfectly. > When I print the params before the if statement, it has a value, but for > some reason, it seems like the params variable is cleared from memory. > I have no idea what is happening. > > Any ideas? > > -- > Posted viahttp://www.ruby-forum.com/.-- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
@Fred,
Thanks man. I agree, that could be the problem. However, to test it out,
I commented out everything inside the if part of the ''criminal
if-else''
and no exception is raised. For example, the new code that works is:
def calculate
#Check if request is from a linked URL or direct request from site
puts "before if statement"
puts params[:entity_selection]
if params[:id]
#puts "in if statement"
#@query = Query.where(:id => params[:id])
#params = eval(@query[0].queryString).to_options
#params[:query_end_date].to_options!
#params[:query_start_date].to_options!
else
puts "in else"
puts params[:entity_selection]
end
So if it were the case that the params hash being mentioned could
overwrite it, then this version of the code would fail, right?
I appreciate the help. I''ll continue to try to figure this out. If this
doesn''t work, it could be anarchy out there. I''m worried.
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On Sep 16, 2:58 pm, "Jonathan S." <li...-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:> @Fred, > > Thanks man. I agree, that could be the problem. However, to test it out, > I commented out everything inside the if part of the ''criminal if-else'' > and no exception is raised. For example, the new code that works is: > > def calculate > > #Check if request is from a linked URL or direct request from site > puts "before if statement" > puts params[:entity_selection] > > if params[:id] > #puts "in if statement" > #@query = Query.where(:id => params[:id]) > #params = eval(@query[0].queryString).to_options > #params[:query_end_date].to_options! > #params[:query_start_date].to_options! > else > puts "in else" > puts params[:entity_selection] > end > > So if it were the case that the params hash being mentioned could > overwrite it, then this version of the code would fail, right? >Except that it''s not mentioned any more - it''s commented out ( mentioned is obviously a rather wooly term) Fred> I appreciate the help. I''ll continue to try to figure this out. If this > doesn''t work, it could be anarchy out there. I''m worried. > > -- > Posted viahttp://www.ruby-forum.com/.-- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
I see what you mean. However, x=3 if false x=2 end puts x This code outputs 3, not nil. And I think that''s a more appropriate analogy. I really don''t understand what''s happening though. Frederick Cheung wrote in post #1022322:> On Sep 16, 2:58pm, "Jonathan S." <li...-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote: >> puts params[:entity_selection] >> end >> >> So if it were the case that the params hash being mentioned could >> overwrite it, then this version of the code would fail, right? >> > > Except that it''s not mentioned any more - it''s commented out > ( mentioned is obviously a rather wooly term) > > Fred-- Posted via http://www.ruby-forum.com/. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
return 3 is the right! the value dont change and never in into if, because you put false...its right 2011/9/16 Jonathan S. <lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org>> I see what you mean. However, > > > x=3 > if false > x=2 > end > > puts x > > > This code outputs 3, not nil. And I think that''s a more appropriate > analogy. I really don''t understand what''s happening though. > > > Frederick Cheung wrote in post #1022322: > > On Sep 16, 2:58pm, "Jonathan S." <li...-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote: > >> puts params[:entity_selection] > >> end > >> > >> So if it were the case that the params hash being mentioned could > >> overwrite it, then this version of the code would fail, right? > >> > > > > Except that it''s not mentioned any more - it''s commented out > > ( mentioned is obviously a rather wooly term) > > > > Fred > > -- > Posted via http://www.ruby-forum.com/. > > -- > You received this message because you are subscribed to the Google Groups > "Ruby on Rails: Talk" group. > To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org > To unsubscribe from this group, send email to > rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org > For more options, visit this group at > http://groups.google.com/group/rubyonrails-talk?hl=en. > >-- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
@leoncio: I was responding to Fred''s suggestion that params was being overwritten because it was mentioned in the if statement in the original code. Forget my replies to Fred, do you have any idea why the params variable is being made nil in the original post? leoncio caminha wrote in post #1022336:> return 3 is the right! the value dont change and never in into if, > because > you put false...its right > > 2011/9/16 Jonathan S. <lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org>-- Posted via http://www.ruby-forum.com/. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On 16 September 2011 16:07, Jonathan S. <lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:> @leoncio: > > I was responding to Fred''s suggestion that params was being overwritten > because it was mentioned in the if statement in the original code. > Forget my replies to Fred, do you have any idea why the params variable > is being made nil in the original post?Use ruby-debug to break into the code and see what is happening. See the Rails Guide on debugging if you do not know how to do that. Colin -- gplus.to/clanlaw -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On Sep 16, 3:48 pm, "Jonathan S." <li...-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:> I see what you mean. However, > > x=3 > if false > x=2 > end >An even better example is puts xyz # should raise name error if false xyz = 1 end puts xyz #=> nil The thing is that params isn''t initially a local variable - it''s a method that then gets shadowed by a local variable, i.e. def xyz "moo" end puts xyz.inspect #=> ''moo'' if false xyz = 1 end puts xyz.inspect #=> nil Fred> puts x > > This code outputs 3, not nil. And I think that''s a more appropriate > analogy. I really don''t understand what''s happening though. > > Frederick Cheung wrote in post #1022322: > > > On Sep 16, 2:58pm, "Jonathan S." <li...-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote: > >> puts params[:entity_selection] > >> end > > >> So if it were the case that the params hash being mentioned could > >> overwrite it, then this version of the code would fail, right? > > > Except that it''s not mentioned any more - it''s commented out > > ( mentioned is obviously a rather wooly term) > > > Fred > > -- > Posted viahttp://www.ruby-forum.com/.-- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On Sep 15, 5:42 pm, "Jonathan S." <li...-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:> Summary of problem: my params hash is being made nil in my controller > without any reason that I can identify. > > Everything was fine until I put this new code as the first lines of code > in my controller. But the block is not being executed because the puts > statement is not evaluated: > > def calculate > > if params[:id] > puts "in if statement" > @query = Query.where(:id => params[:id]) > params = eval(@query[0].queryString).to_optionsUnrelated, but in the name of all that is holy don''t do this. Look into the ''serialize'' method: http://api.rubyonrails.org/classes/ActiveRecord/Base.html#method-c-serialize for a cleaner, faster, safer way to stash whole data structures in the DB. --Matt Jones PS: Also, Query.find(params[:id]) is a good bit more understandable than doing a where and then getting the first element. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On 16 September 2011 16:07, Jonathan S. <lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:> @leoncio: > > I was responding to Fred''s suggestion that params was being overwritten > because it was mentioned in the if statement in the original code. > Forget my replies to Fred, do you have any idea why the params variable > is being made nil in the original post?I think perhaps you are thinking that a local variable created inside an if block will disappear at the end of the block, so that the original variable is restored. Wrong. Colin> > > leoncio caminha wrote in post #1022336: >> return 3 is the right! the value dont change and never in into if, >> because >> you put false...its right >> >> 2011/9/16 Jonathan S. <lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> > > -- > Posted via http://www.ruby-forum.com/. > > -- > You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. > To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org > To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org > For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en. > >-- gplus.to/clanlaw -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
@Matt, Serializing is definitely the right way to go. I''ll get into that. And of course, I''ll use the find method on the query. Awesome advice. Very appreciative. Matt Jones wrote in post #1022343:> On Sep 15, 5:42pm, "Jonathan S." <li...-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote: >> puts "in if statement" >> @query = Query.where(:id => params[:id]) >> params = eval(@query[0].queryString).to_options > > Unrelated, but in the name of all that is holy don''t do this. Look > into the ''serialize'' method: > > http://api.rubyonrails.org/classes/ActiveRecord/Base.html#method-c-serialize > > for a cleaner, faster, safer way to stash whole data structures in the > DB. > > --Matt Jones > > PS: Also, Query.find(params[:id]) is a good bit more understandable > than doing a where and then getting the first element.-- Posted via http://www.ruby-forum.com/. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
@Fred, Matt: Awesome example and good explanation. I''ll have to dig into this issue as well. Thanks to everyone for the help! Amazing group. -- Posted via http://www.ruby-forum.com/. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.