How do I use ViewScripts on Zend_Form File Elements?

This is not a simple or ideal solution because it requires an extension of the File decorator... but it's rather frustrating that they didn't make the effort to separate the hidden element generation logic from the file input generation logic. I'm not sure if the file view helper handles the issue of an element being an array (that seems to be the reason they did it this way.)

Extension of File Decorator: (the commented out part is what causes the extra input to be generated.)

<?php

class Sys_Form_Decorator_File extends Zend_Form_Decorator_File {

  public function render($content) {

    $element = $this->getElement();
    if (!$element instanceof Zend_Form_Element) {return $content;}

    $view = $element->getView();
    if (!$view instanceof Zend_View_Interface) {return $content;}

    $name = $element->getName();
    $attribs = $this->getAttribs();
    if (!array_key_exists('id', $attribs)) {$attribs['id'] = $name;}

    $separator = $this->getSeparator();
    $placement = $this->getPlacement();
    $markup = array();
    $size = $element->getMaxFileSize();

    if ($size > 0) {

      $element->setMaxFileSize(0);
      $markup[] = $view->formHidden('MAX_FILE_SIZE', $size);

    }

    if (Zend_File_Transfer_Adapter_Http::isApcAvailable()) {

      $apcAttribs = array('id' => 'progress_key');
      $markup[] = $view->formHidden('APC_UPLOAD_PROGRESS', uniqid(), $apcAttribs);

    }

    else if (Zend_File_Transfer_Adapter_Http::isUploadProgressAvailable()) {

      $uploadIdAttribs = array('id' => 'progress_key');
      $markup[] = $view->formHidden('UPLOAD_IDENTIFIER', uniqid(), $uploadIdAttribs);

    }

    /*

    if ($element->isArray()) {

      $name .= "[]";
      $count = $element->getMultiFile();

      for ($i = 0; $i < $count; ++$i) {

        $htmlAttribs = $attribs;
        $htmlAttribs['id'] .= '-' . $i;
        $markup[] = $view->formFile($name, $htmlAttribs);

      }

    }

    else {$markup[] = $view->formFile($name, $attribs);} 

    */

    $markup = implode($separator, $markup);

    switch ($placement) {

      case self::PREPEND: return $markup . $separator . $content;
      case self::APPEND:
      default: return $content . $separator . $markup;

    }

  }

 }

?>

Form setup in controller action:

$form = new Zend_Form();
$form->addElement(new Zend_Form_Element_File('file'));
$form->file->setLabel('File');
$form->file->setDescription('Description goes here.');

$decorators = array();
$decorators[] = array('File' => new Sys_Form_Decorator_File());
$decorators[] = array('ViewScript', array('viewScript' => '_formElementFile.phtml'));
$form->file->setDecorators($decorators);

$this->view->form = $form;

In action view:

<?php echo $this->form; ?>

In element script:

<div class="field" id="field_<?php echo $this->element->getId(); ?>">

<?php if (0 < strlen($this->element->getLabel())) : ?>
<?php echo $this->formLabel($this->element->getName(), $this->element->getLabel());?>
<?php endif; ?>

<span class="value">
<?php 

echo $this->{$this->element->helper}(

  $this->element->getName(),
  $this->element->getValue(),
  $this->element->getAttribs()

);

?>
</span>

<?php if (0 < $this->element->getMessages()->length) : ?>
<?php echo $this->formErrors($this->element->getMessages()); ?>
<?php endif; ?>

<?php if (0 < strlen($this->element->getDescription())) : ?>
<span class="hint"><?php echo $this->element->getDescription(); ?></span>
<?php endif; ?>

</div>

Output should be:

<form enctype="multipart/form-data" action="" method="post">
<dl class="zend_form">
<input type="hidden" name="MAX_FILE_SIZE" value="134217728" id="MAX_FILE_SIZE" />
<div class="field" id="field_file">
<label for="file">File</label>
<span class="value"><input type="file" name="file" id="file" /></span>
<span class="hint">Description goes here.</span>
</div>
</dl>
</form>

A problem with this solution is that the hidden elements don't render within the viewscript; this might be a problem if you're using the div as a selector in a client-side script...

I've found a work-around that avoids the ViewScript altogether.

First, the element definition:

$this->addElement('file', 'upload_file', array(
    'disableLoadDefaultDecorators' => true,
    'decorators' => array(
        'File',
        array(array('Value'=>'HtmlTag'), array('tag'=>'span','class'=>'value')),
        'Errors',
        'Description',
        'Label',
        array(array('Field'=>'HtmlTag'), array('tag'=>'div','class'=>'field file')),
    ),
    'label' => 'Upload File',
    'required' => false,
    'filters' => array('StringTrim'),
    'validators' => array(),
));

Second, after the form class has been instantiated, I mimic the behavior of my ViewScript:

$field = $form->getElement('upload_file');
$decorator = $field->getDecorator('Field');
$options = $decorator->getOptions();
$options['id'] = 'field_' . $field->getId();
if ($field->hasErrors()) {
    $options['class'] .= ' errors';
}
$decorator->setOptions($options);

I guess that I should look into class-based decorators. Maybe there's more flexibility there?

The easiest thing to do is to add no markup at all to the output in your custom File Decorator:

class Custom_Form_Decorator_File extends Zend_Form_Decorator_File {
        public function render($content) {
                return $content;
        }
}

now you can do whatever you want in your viewscript for this file element (output the file input field and all hidden fields you need on your own).