Form validating the content of an uploaded XML file

I have a form where an XML file is uploaded. After the form is submitted I have to check the content of a pair of tags in the XML file. If the content of the tags is different from some expected, an error should be shown next to the form.

I don't know exactly how to organize this code, any help?

tags: prevalidation, postvalidation

Solution

You have several places to perform this check:

in the action that create the form
in the form using a custom validator
in the model class (wich isn't really recommended ...)

I prefer the custom validator because if you have to re-use the form somewhere else you won't have to re-implement the logic of checking the xml.

So in your sfForm class, add a custom validator to your file widget:

class MyForm extends sfForm
{
  public function configure()
  {
    // .. other widget / validator configuration

    $this->validatorSchema['file'] = new customXmlFileValidator(array(
      'required'  => true,
    ));

And inside your new validator at /lib/validator/customXmlFileValidator.class.php:

// you extend sfValidatorFile, so you keep the basic file validator
class customXmlFileValidator extends sfValidatorFile
{
  protected function configure($options = array(), $messages = array())
  {
    parent::configure($options, $messages);

    // define a custom message for the xml validation
    $this->addMessage('xml_invalid', 'The XML is not valid');
  }

  protected function doClean($value)
  {
    // it returns a sfValidatedFile object
    $value = parent::doClean($value);

    // load xml file
    $doc = new DOMDocument();
    $doc->load($this->getTempName());

    // do what ever you want with the dom to validate your xml
    $xpath = new DOMXPath($doc);
    $xpath->query('/my/xpath');

    // if validation failed, throw an error
    if (true !== $result)
    {
      throw new sfValidatorError($this, 'xml_invalid');
    }

    // otherwise return the sfValidatedFile object from the extended class
    return $value;
  }
}

Do not forget to clear your cache php symfony cc and it should be ok.