symfony - Symfony2 invalid token with big files -

i'm having problem token , file field form.

the validation of form this:

public function getdefaultoptions(array $options) {     $collectionconstraint = new collection(array(         'fields' => array(             'file' => new file(                 array(                     'maxsize' => '2m',                     'mimetypes' => array(                         'application/pdf', 'application/x-pdf',                         'image/png', 'image/jpg', 'image/jpeg', 'image/gif',                     ),                 )             ),         )     ));      return array(         'validation_constraint' => $collectionconstraint } 

when upload invalid size file(~5mb) error hope:

the file large. allowed maximum size 2m bytes 

but when upload big file(~30mb) error changes:

the csrf token invalid. please try resubmit form uploaded file large. please try upload smaller file 

the problem error token. i've in form {{ form_rest(form) }} code. think error change because of this: how increase upload limit files on symfony 2 form?

i don't want increase upload limit. want token error doesn't show.

php (not symfony) rejects file if bigger configured values in:

post_max_size upload_max_filesize 

because of csrf-error thrown.

if want avoid have increase upload limit. way. if add file-constraint should no risk.