thr3ads.net - Rails - can someone explain this code to me? [Mar 2007]

If this information is useful, please help other people find it:
Share via:

treebeard

2007-Mar-14 18:38 UTC

can someone explain this code to me?

taken from here using acts_as_fu, possible work for acts as attachment
as well
http://beast.caboo.se/forums/2/topics/870

Image.transaction do
  images = params[:image].collect { |img| Image.create(:uploaded_data =>
img }
end unless params[:image].nil?


basically i think i can have a form with a dynamic amount of file fields
for each file i would like to upload. Image i guess is the table that
will be storing the photos.

i am confused at the block part. basically is this converting the hash
into an array, going through each index in the array, and saving each
photo into the Image table?

-- 
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-/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
-~----------~----~----~----~------~----~------~--~---

Alex Wayne

2007-Mar-14 18:52 UTC

head link

Re: can someone explain this code to me?

treebeard wrote:> taken from here using acts_as_fu, possible work for acts as attachment
> as well
> http://beast.caboo.se/forums/2/topics/870
> 
> Image.transaction do
>   images = params[:image].collect { |img| Image.create(:uploaded_data =>
> img }
> end unless params[:image].nil?
> 
> 
> basically i think i can have a form with a dynamic amount of file fields
> for each file i would like to upload. Image i guess is the table that
> will be storing the photos.
> 
> i am confused at the block part. basically is this converting the hash
> into an array, going through each index in the array, and saving each
> photo into the Image table?
Collect takes every element in the array and replaces it with the result 
of the passed block.  The unless after the transaction block prevent the 
block from executing if the condition is true.

So you could rewrite the code like this:

  unless params[:image].nil?
    Image.transaction do
      images = []
      params[:image].each do |img|
        images << Image.create(:uploaded_data => img)
      end
    end
  end

But what fun is that?  Although, personally I don''t like a condition 
after a multi-line block like that.  You don''t realize it will be 
conditionally executed until the end of it.  But it''s a great case for 
the use of collect.

-- 
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-/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
-~----------~----~----~----~------~----~------~--~---

javier ramirez

2007-Mar-14 18:56 UTC

head link

Re: can someone explain this code to me?

> images=params[:image].collect{|img|Image.create(:uploaded_data=>img}
>
> i am confused at the block part. basically is this converting the hash
> into an array, going through each index in the array, and saving each
> photo into the Image table?
>   Assuming Image is a plain old ActiveRecord class (no overwritten 
methods) then yes. The collect would iterate over every image saving the 
records (the records would contain just two fields with values: id and 
uploaded_data) and returning finally an array with the AR objects created.

regards

javier ramirez

-- 
--------
Estamos de estreno... si necesitas llevar el control de tus gastos visita
http://www.gastosgem.com !!Es gratis!!


--~--~---------~--~----~------------~-------~--~----~
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
-~----------~----~----~----~------~----~------~--~---

treebeard

2007-Mar-14 18:59 UTC

head link

Re: can someone explain this code to me?

hi Alex, thanks for the post. however, im still trying to understand 
this...

images = []
params[:image].each do |img|
     images << Image.create(:uploaded_data => img)
end


params[:image]....the actual file is here correct?

params[:image][:uploaded_data]
and is that the same as this?

params[''0''][:uploaded_data]
params[''1''][:uploaded_data]

etc... for multiple files?

also, what is the purpose for images? cant one just call

Image.create(:uploaded_data => img) inside the block?


thanks.








Alex Wayne wrote:> treebeard wrote:
>> taken from here using acts_as_fu, possible work for acts as attachment
>> as well
>> http://beast.caboo.se/forums/2/topics/870
>> 
>> Image.transaction do
>>   images = params[:image].collect { |img| Image.create(:uploaded_data
=>
>> img }
>> end unless params[:image].nil?
>> 
>> 
>> basically i think i can have a form with a dynamic amount of file
fields
>> for each file i would like to upload. Image i guess is the table that
>> will be storing the photos.
>> 
>> i am confused at the block part. basically is this converting the hash
>> into an array, going through each index in the array, and saving each
>> photo into the Image table?
> 
> Collect takes every element in the array and replaces it with the result 
> of the passed block.  The unless after the transaction block prevent the 
> block from executing if the condition is true.
> 
> So you could rewrite the code like this:
> 
>   unless params[:image].nil?
>     Image.transaction do
>       images = []
>       params[:image].each do |img|
>         images << Image.create(:uploaded_data => img)
>       end
>     end
>   end
> 
> But what fun is that?  Although, personally I don''t like a
condition
> after a multi-line block like that.  You don''t realize it will be 
> conditionally executed until the end of it.  But it''s a great case
for
> the use of collect.

-- 
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-/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
-~----------~----~----~----~------~----~------~--~---

Rick Olson

2007-Mar-14 19:24 UTC

head link

Re: can someone explain this code to me?

> params[:image]....the actual file is here correct?
If you look at the form, it''s probably using a group of file fields
with a name of ''image[]''.  Get params have no concept of
arrays, so
this is basically posted like this:

image[]=FILE1&image[]=FILE2

Rails parses fields with names ending in [] into an array.  So
params[:image] is an array of the images from the file field.
> params[:image][:uploaded_data]
> and is that the same as this?
Nope.
> params[''0''][:uploaded_data]
> params[''1''][:uploaded_data]
>
> etc... for multiple files?
It''s an array... params[:image][0]
> also, what is the purpose for images? cant one just call
>
> Image.create(:uploaded_data => img) inside the block?
Yup.  Alex was just showing an example using #each instead of
#collect.  #collect will return an array of the created images.  With
#each, you have to populate an images array manually.

-- 
Rick Olson
http://lighthouseapp.com
http://weblog.techno-weenie.net
http://mephistoblog.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-/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
-~----------~----~----~----~------~----~------~--~---

Xavier Noria

2007-Mar-14 20:26 UTC

head link

Re: can someone explain this code to me?

On Mar 14, 2007, at 7:52 PM, Alex Wayne wrote:
> Collect takes every element in the array and replaces it with the  
> result
> of the passed block.
Just for the record, collect does not modify the array in place, in  
that sense no element is replaced. (Replacement is provided by collect!)

-- fxn


--~--~---------~--~----~------------~-------~--~----~
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
-~----------~----~----~----~------~----~------~--~---

treebeard

2007-Mar-15 15:28 UTC

head link

Re: can someone explain this code to me?

thanks all and thanks rick for the code you posted over in beast!


-- 
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-/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
-~----------~----~----~----~------~----~------~--~---

Rails - Mar 2007 - can someone explain this code to me?

can someone explain this code to me?

Re: can someone explain this code to me?

Re: can someone explain this code to me?

Re: can someone explain this code to me?

Re: can someone explain this code to me?

Re: can someone explain this code to me?

Re: can someone explain this code to me?