File interface

Looking to go from a file uri to a file object without reading the files table yourself with SQL? Try file_uri_to_object from the media.module! Oh yes!

I couldn't find any documentation about this anywhere so here's what I did:

/**
 * Implementation of hook_form_FORM_ID_alter
 **/
hook_form_FORM_ID_alter(&$form, &$form_state, $form_id){

$form['field_MY_FILE_FIELD_NAME']['und'][0]['#process'][] = 'my_processing_function';

}

/**
 * My Ajax Upload File Processing Function
 **/
function my_processing_function($element, &$form_state){

// check to see if it's submitted and if there's a file
if ($form_state['submitted'] && $element['#value']['fid']){

  // Do stuff to the file here
  $fid = $element['#value']['fid']
}

// make sure we return the element when we're done
return $element;
}

Here is information on how to save a file that has been uploaded using a form and the type managed_file. The file is normally saved only temporarily and will be deleted automatically during CRON runs.

The form code looks something like this,

function MYMODULE_form ($form, &$form_state){
  $form['MY_IMAGE_NAME'] = array(
    '#title' => t('My Image'),
    '#type' => 'managed_file',
    '#description' => t('Please upload an image!'),
    '#default_value' => variable_get('MY_IMAGE_NAME', ''),
    '#progress_indicator' => 'bar',
    '#upload_location' => 'public://',
  );
}

function MYMODULE_form_submit ($form, &$form_state) {
  /*Update the status to permanent*/
  $form['MY_IMAGE_NAME']['#file']->status = FILE_STATUS_PERMANENT;
  /*Save the updated file information to the database*/
  file_save($form['MY_IMAGE_NAME']['#file']);
}

You can check that the file is permanent by looking in the "file_managed" table in the "status" field. 0 means temporary, 1 means permanent.

I hope this helps someone. It was a little tricky for me to figure out.

I have a content type with some file fields
When I insert the content for the first time I know that all the files are new in hook_node_insert

But in hook_node_update how to know if this is new uploaded file when updated the content or the files has not been changed?

How can I change the location of where the uploaded files are saved in my submit function?

I configured the cck file field in my content type to upload to private and currently Drupal is saving it in private://<uid>/. However, I want the upload file to go to private://<uid>/<id>/<subdirectory>/ where and are generated in the submit function. I tried:

        $files = $form_state['values'][$field_name][LANGUAGE_NONE];
        foreach ( $files as $file )
        {
            $file_obj = file_load ( $file['fid'] );
            if ( $file_obj )
            {
                $file_obj->status = FILE_STATUS_PERMANENT;
                $file_obj->uri = $directory . "/" . $file_obj->filename;
                file_save ( $file_obj );
            }
        }

But that didn't work, I kept getting:
"The file used in the Plots field may not be referenced.
Warning: filesize() [function.filesize]: stat failed for private://2/pp/plots/volcano_1.0mpa.png in file_save() (line 570 of /projects/sysint/web_db/servers/drupal/drupal-7.19/includes/file.inc)."

All help is appreciated.

Actually i m getting some problem in displaying the information which has been filled in the form by the user... And i wanted to show only some of the information in the main page.like e-mail message and so on..... so would you please give me some information regarding to it....

How to use "define('FILE_EXISTS_REPLACE', 1)" in code ..?

I want to replace a file including the database entry into a given fid ..
Can you help me by sample snippets of code ..

It would be useful to have a function in the File API to return a file schema's base URL, as it seems to be hardcoded for example for private schema - currently '/system/files/'.