Hey all,
when a user submits a new item in my app, I want to generate a random
7-digit number for that item. So far, I am a little unclear as to how
this should work.
Here is what I have in my item.rb model
# generate a random item number for each new listing
def generate_item_number
rand(9999999).to_s.center(7, rand(9).to_s)
end
Now, my question is......
Should I create this random number in my items controller right before
it saves the item to the DB?
def create
# associate user to new item listing
@item = @current_user.items.build(params[:item])
-------------GENERATE RANDOM NUMBER HERE--------------???
if @item.save
flash[:notice] = ''Your item has been successfully
submitted!''
redirect_to items_path
else
flash[:notice] = "Uh Oh! Your item cannot be posted yet."
render :action => "new"
end
end
I am thinking that is best method for doing this, but how would I
actually do it? Is this the cleanest way to produce this number?
Thanks!
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On 1 Sep 2008, at 18:34, CPerry wrote:> > Hey all, > > when a user submits a new item in my app, I want to generate a random > 7-digit number for that item. So far, I am a little unclear as to how > this should work. > > Here is what I have in my item.rb model > > # generate a random item number for each new listing > def generate_item_number > rand(9999999).to_s.center(7, rand(9).to_s) > endI would say 1000000 + rand(8999999) is slightly more obvious.> > > Now, my question is...... > > Should I create this random number in my items controller right before > it saves the item to the DB? > > def create > # associate user to new item listing > @item = @current_user.items.build(params[:item]) > -------------GENERATE RANDOM NUMBER HERE--------------??? > if @item.save > flash[:notice] = ''Your item has been successfully submitted!'' > redirect_to items_path > else > flash[:notice] = "Uh Oh! Your item cannot be posted yet." > render :action => "new" > end > end > > I am thinking that is best method for doing this, but how would I > actually do it? Is this the cleanest way to produce this number? >I''d do it in a model before_create/before_save. This shouldn''t be the controller''s concern Fred> Thanks! > >--~--~---------~--~----~------------~-------~--~----~ 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-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
Thanks Frederick, I see what you area saying now. So, in my model, I have now added class Item < ActiveRecord::Base #add associations belongs_to :user before_save :generate_item_number end Now, how would I actually have this random number written to my "item_number" column in the DB? Should I use a hidden field that calls that method? --Cory On Sep 1, 1:52 pm, Frederick Cheung <frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> On 1 Sep 2008, at 18:34, CPerry wrote: > > > > > Hey all, > > > when a user submits a new item in my app, I want to generate a random > > 7-digit number for that item. So far, I am a little unclear as to how > > this should work. > > > Here is what I have in my item.rb model > > > # generate a random item number for each new listing > > def generate_item_number > > rand(9999999).to_s.center(7, rand(9).to_s) > > end > > I would say 1000000 + rand(8999999) is slightly more obvious. > > > > > Now, my question is...... > > > Should I create this random number in my items controller right before > > it saves the item to the DB? > > > def create > > # associate user to new item listing > > @item = @current_user.items.build(params[:item]) > > -------------GENERATE RANDOM NUMBER HERE--------------??? > > if @item.save > > flash[:notice] = ''Your item has been successfully submitted!'' > > redirect_to items_path > > else > > flash[:notice] = "Uh Oh! Your item cannot be posted yet." > > render :action => "new" > > end > > end > > > I am thinking that is best method for doing this, but how would I > > actually do it? Is this the cleanest way to produce this number? > > I''d do it in a model before_create/before_save. This shouldn''t be the > controller''s concern > > Fred > > > Thanks!--~--~---------~--~----~------------~-------~--~----~ 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-/JYPxA39Uh5TLH3MbocFFw@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 concur with Fred. Keep it in the model. If you want to make it more obvious and/or reusable create a public class method for this and call that from the before_save/update filters. As far as true random number generation, that is more of a political discussion. Using rand should be adequate. I would like to ask, is the number supposed to be unique across that model, because in theory it could occur 10X in a row and would not be truly random. If you want something that is a big number/pkey for that item, i would also look at using a hash on the item using the model primary key as salt. That in theory can give you a random looking number/string but in reality to unique like a pkey too. just a thought. H On Sep 1, 1:52 pm, Frederick Cheung <frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> On 1 Sep 2008, at 18:34, CPerry wrote: > > > > > Hey all, > > > when a user submits a new item in my app, I want to generate a random > > 7-digit number for that item. So far, I am a little unclear as to how > > this should work. > > > Here is what I have in my item.rb model > > > # generate a random item number for each new listing > > def generate_item_number > > rand(9999999).to_s.center(7, rand(9).to_s) > > end > > I would say 1000000 + rand(8999999) is slightly more obvious. > > > > > Now, my question is...... > > > Should I create this random number in my items controller right before > > it saves the item to the DB? > > > def create > > # associate user to new item listing > > @item = @current_user.items.build(params[:item]) > > -------------GENERATE RANDOM NUMBER HERE--------------??? > > if @item.save > > flash[:notice] = ''Your item has been successfully submitted!'' > > redirect_to items_path > > else > > flash[:notice] = "Uh Oh! Your item cannot be posted yet." > > render :action => "new" > > end > > end > > > I am thinking that is best method for doing this, but how would I > > actually do it? Is this the cleanest way to produce this number? > > I''d do it in a model before_create/before_save. This shouldn''t be the > controller''s concern > > Fred > > > Thanks!--~--~---------~--~----~------------~-------~--~----~ 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-/JYPxA39Uh5TLH3MbocFFw@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 1, 7:26 pm, CPerry <c...-jEJZ73ctDLTqlBn2x/YWAg@public.gmane.org> wrote:> Thanks Frederick, I see what you area saying now. > > So, in my model, I have now added > > class Item < ActiveRecord::Base > #add associations > belongs_to :user > > before_save :generate_item_number > > end > > Now, how would I actually have this random number written to my > "item_number" column in the DB? Should I use a hidden field that calls > that method? >No. just do all that in the before_save, ie def my_before_save self.item_number = ... end (you might want it to be a before_create rather than a before_save) Fred> --Cory > > On Sep 1, 1:52 pm, Frederick Cheung <frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> > wrote: > > > On 1 Sep 2008, at 18:34, CPerry wrote: > > > > Hey all, > > > > when a user submits a new item in my app, I want to generate a random > > > 7-digit number for that item. So far, I am a little unclear as to how > > > this should work. > > > > Here is what I have in my item.rb model > > > > # generate a random item number for each new listing > > > def generate_item_number > > > rand(9999999).to_s.center(7, rand(9).to_s) > > > end > > > I would say 1000000 + rand(8999999) is slightly more obvious. > > > > Now, my question is...... > > > > Should I create this random number in my items controller right before > > > it saves the item to the DB? > > > > def create > > > # associate user to new item listing > > > @item = @current_user.items.build(params[:item]) > > > -------------GENERATE RANDOM NUMBER HERE--------------??? > > > if @item.save > > > flash[:notice] = ''Your item has been successfully submitted!'' > > > redirect_to items_path > > > else > > > flash[:notice] = "Uh Oh! Your item cannot be posted yet." > > > render :action => "new" > > > end > > > end > > > > I am thinking that is best method for doing this, but how would I > > > actually do it? Is this the cleanest way to produce this number? > > > I''d do it in a model before_create/before_save. This shouldn''t be the > > controller''s concern > > > Fred > > > > Thanks!--~--~---------~--~----~------------~-------~--~----~ 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-/JYPxA39Uh5TLH3MbocFFw@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 -~----------~----~----~----~------~----~------~--~---
Excellent, Thanks Frederick, it works perfectly! @Blasterpal.... Yes, the number does truly need to be random as well as unique across the model as I would not want 2 items to ever have the same item number. Most of these items will (later on) be searched and looked up by this number, so obviously duplicates can''t happen. So what you are saying is that my rand sequence I posted above could at some point generate the same number over again? --Cory On Sep 1, 2:58 pm, Frederick Cheung <frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> On Sep 1, 7:26 pm, CPerry <c...-jEJZ73ctDLTqlBn2x/YWAg@public.gmane.org> wrote: > > > Thanks Frederick, I see what you area saying now. > > > So, in my model, I have now added > > > class Item < ActiveRecord::Base > > #add associations > > belongs_to :user > > > before_save :generate_item_number > > > end > > > Now, how would I actually have this random number written to my > > "item_number" column in the DB? Should I use a hidden field that calls > > that method? > > No. just do all that in the before_save, ie > > def my_before_save > self.item_number = ... > end > > (you might want it to be a before_create rather than a before_save) > > Fred > > > --Cory > > > On Sep 1, 1:52 pm, Frederick Cheung <frederick.che...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> > > wrote: > > > > On 1 Sep 2008, at 18:34, CPerry wrote: > > > > > Hey all, > > > > > when a user submits a new item in my app, I want to generate a random > > > > 7-digit number for that item. So far, I am a little unclear as to how > > > > this should work. > > > > > Here is what I have in my item.rb model > > > > > # generate a random item number for each new listing > > > > def generate_item_number > > > > rand(9999999).to_s.center(7, rand(9).to_s) > > > > end > > > > I would say 1000000 + rand(8999999) is slightly more obvious. > > > > > Now, my question is...... > > > > > Should I create this random number in my items controller right before > > > > it saves the item to the DB? > > > > > def create > > > > # associate user to new item listing > > > > @item = @current_user.items.build(params[:item]) > > > > -------------GENERATE RANDOM NUMBER HERE--------------??? > > > > if @item.save > > > > flash[:notice] = ''Your item has been successfully submitted!'' > > > > redirect_to items_path > > > > else > > > > flash[:notice] = "Uh Oh! Your item cannot be posted yet." > > > > render :action => "new" > > > > end > > > > end > > > > > I am thinking that is best method for doing this, but how would I > > > > actually do it? Is this the cleanest way to produce this number? > > > > I''d do it in a model before_create/before_save. This shouldn''t be the > > > controller''s concern > > > > Fred > > > > > Thanks!--~--~---------~--~----~------------~-------~--~----~ 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-/JYPxA39Uh5TLH3MbocFFw@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 1, 8:26 pm, CPerry <c...-jEJZ73ctDLTqlBn2x/YWAg@public.gmane.org> wrote:> Excellent, Thanks Frederick, it works perfectly! > > @Blasterpal.... > > Yes, the number does truly need to be random as well as unique across > the model as I would not want 2 items to ever have the same item > number. Most of these items will (later on) be searched and looked up > by this number, so obviously duplicates can''t happen. > > So what you are saying is that my rand sequence I posted above could > at some point generate the same number over again? >Absolutely (it wouldn''t be very random if it never produced values it has already produced). Any individual number has the same chance of being produced at any given time. if you want a uniqueness guarantee you''ll have to enforce that yourself (and to be double sure stick a unique index on the relevant column). Fred --~--~---------~--~----~------------~-------~--~----~ 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-/JYPxA39Uh5TLH3MbocFFw@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 -~----------~----~----~----~------~----~------~--~---