Propel can create Models with autoset created_at and Updated_at field, but dont include autoset for Created_by and Updated_by field, because this fields are most aplication dependent. We can set Propel to build models with autosetting Created_by and Updated_by fields (and any other fields) extending SfObjectBuilder. In the forum message 7535 Tamcy give us a good example. Here I post a SFObjectBuilder extension class (in this example I check if using SfGuardPlugin for user Class).

<?php
/* I recomend put this class out Symfony Folder.
*  If you put this class in some project folder
* you can use include_once 'symfony/addon/propel/builder/SfObjectBuilder.php'
* @author     Boris Duin 
 */
require_once 'sfObjectBuilder.php';
class SfObjectAdvBuilder extends SfObjectBuilder
{
  */Extend Method addSave
  protected function addSave(&$script)
  {
    $tmp = '';
    parent::addSave($tmp);
 
    $date_script = '';
 
    $user_updated = false;
    $user_created = false;
    foreach ($this->getTable()->getColumns() as $col)
    {
      $clo = strtolower($col->getName());
 
      if (!$user_created && $clo == 'created_by')
      {
        $user_created = true;
        $date_script .= "
    if (\$this->isNew() && !\$this->isColumnModified('created_by'))
    {
      \$user = sfContext::getInstance()->getUser();
      if (\$user instanceof sfGuardSecurityUser)
        \$this->setCreatedby(\$user->getUsername())
    }
";
      }
      else if (!$user_updated && $clo == 'updated_by')
      {
       $user_updated = true;
        $date_script .= "
    if (\$this->isModified() && !\$this->isColumnModified('updated_by'))
    {
      \$user = sfContext::getInstance()->getUser();
      if (\$user instanceof sfGuardSecurityUser)
        \$this->setUpdatedby(\$user->getUsername())
    }
";
      }
    }
 
    $tmp = preg_replace('/{/', '{'.$date_script, $tmp, 1);
    $script .= $tmp;
  }
}

Note: I write this class for synfony 0.9.x versión. Yesterday I was refactoring this class for 1.0.x version, but I leave this in my house, :(. To set propel to use this class you must edit config/propel.ini. Replace this line

propel.builder.object.class = symfony.addon.propel.builder.SfObjectBuilder

for

propel.builder.object.class = route.to.my.class.SfObjectAdvBuilder

Example: If you put this class in your Project/Lib folder you can set the line:

propel.builder.object.class = ${propel.output.dir}.lib.SfObjectAdvBuilder

Now, when you run symfony propel-build-model, propel will use this class and add autoset code for created_by and Updated_by field. Here an example of models class generated by propel (symfony 0.9.x):

public function save($con = null)
    {
    if ($this->isNew() && !$this->isColumnModified('created_by'))
    {
      $user = sfContext::getInstance()->getUser();
      if ($user instanceof sfGuardSecurityUser)
        $this->setCreatedby($user->getUsername());
    }
 
    if ($this->isNew() && !$this->isColumnModified('created_at'))
    {
      $this->setCreatedAt(time());
    }
 
    if ($this->isModified() && !$this->isColumnModified('updated_by'))
    {
      $user = sfContext::getInstance()->getUser();
      if ($user instanceof sfGuardSecurityUser)
        $this->setUpdatedby($user->getUsername());
    }
 
    if ($this->isModified() && !$this->isColumnModified('updated_at'))
    {
      $this->setUpdatedAt(time());
    }

I will investigate how to create a Symfony plugin using maybe Behavior like other Symfony-propel plugins

You can pass aditional parameters to input_auto_complete_tag helper. By default, autocompleter pass only object-referer value. For aditional parameter you need use 'with' in $completion_options array. in view layer:

<
<?php echo object_input_tag($model, 'getFilter', array ('size' => 20, 'control_name' => 'filter',));?>
?php echo input_auto_complete_tag('field_to_search','','module/autocomplete', array('autocomplete'=>'off'),array('use_style'=>true,'with'=> " value+'&filter='+$('filter').value"))?>

you must put '" value' (with whitespace) because javascript fail (a little symfony bug). Aditional parameters must go after value.

in control layer:

 public function executeAutocomplete(){
    $search=$this->getRequestParameter('field_to_search');
    $filter=$this->getRequestParameter('filter');
....
}

now you can use field_to_search and filter to construct any query in model layer ans show this in AutocompleteSuccess.php view or another view that you define. this was tested in synfony version > 0.9. Check your version, and review your javascripthelper helper to verify if your input_auto_complete_tag helper supports 'with' option