[Catalyst] Where is the form field lost?

[Stephen Howard]

I believe your problem lies in the browser itself.  I know, for  
example, that browsers do not send empty values for checkboxes that  
remain unchecked - they simply eliminate that field from the form  
submission altogether. Sounds like file fields might be the same way.   
Your best bet is to use a bit of scripting on the browser side to mark  
a hidden field to stand in for the empty file field.

- Stephen

On Jan 24, 2010, at 7:03 AM, Octavian Rasnita wrote:

> Hi,
>
> After sending a form with a file upload field, that field is lost if  
> no file
> was attached, just like when the form doesn't contain that file  
> upload field
> at all.
>
> I have tried to check Catalyst, Catalyst::Request, Catalyst::Engine,
> HTTP::Body and HTTP::Body::MultiPart in order to find where are the  
> file upload fields lost, but I
> couldn't find it.
>
> I need to know if the form didn't have a file upload field, or if it  
> had it
> but no file was uploaded.
>
> I have printed Dumper $request->_body in  
> Catalyst::Engine::prepare_uploads,
> and when a file is uploaded, it looks like:
>
> $VAR1 = bless( {
>                'content_length' => '1727',
>                'tmpdir' => 'C:\\DOCUME~1\\Octavian\\LOCALS~1\\Temp',
>                'part' => {},
>                'buffer' => '',
>                'state' => 'done',
>                'chunk_buffer' => '',
>                'body' => undef,
>                'content_type' => 'multipart/form-data;
> boundary=---------------------------7da8c3070458',
>                'length' => 1727,
>                'boundary' =>  
> '---------------------------7da8c3070458',
>                'chunked' => '',
>                'upload' => {
>                              'file' => {
>                                          'headers' => {
>                                                         'Content- 
> Type' =>
> 'text/plain',
>                                                         'Content- 
> Disposition'
> => 'form-data; name="file"; filename="E:\\zzzz_cool.txt"'
>                                                       },
>                                          'tempname' =>
> 'C:\\DOCUME~1\\Octavian\\LOCALS~1\\Temp\\PrJ0ruNzzR',
>                                          'name' => 'file',
>                                          'size' => 44,
>                                          'filename' => 'E:\ 
> \zzzz_cool.txt'
>                                        }
>                            },
>                'param' => {},
>              }, 'HTTP::Body::MultiPart' );
>
>
> If no file was uploaded, it prints:
>
> $VAR1 = bless( {
>                'content_length' => '1699',
>                'tmpdir' => 'C:\\DOCUME~1\\Octavian\\LOCALS~1\\Temp',
>                'part' => {},
>                'buffer' => '',
>                'state' => 'done',
>                'chunk_buffer' => '',
>                'body' => undef,
>                'content_type' => 'multipart/form-data;
> boundary=---------------------------7da1573870458',
>                'length' => 1699,
>                'boundary' =>  
> '---------------------------7da1573870458',
>                'chunked' => '',
>                'upload' => {},
>                'param' => {},
>              }, 'HTTP::Body::MultiPart' );
>
> So the 'upload' key doesn't contain anything, not even the name of  
> the file
> upload field.
>
> Can you give me a hint where I should look for finding where the  
> empty file
> upload field is skipped if it is empty?
>
> Thank you.
>
> Octavian
>
>
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