I've been thinking about the Simple Zend_Form File Upload Example that I discussed last month.
To recap, if you haven't read the comments, if the form fails to validate for some reason then you get a nasty error:
Warning: htmlspecialchars() expects parameter 1 to be string, object given in /Users/rob/Sites/akrabat/Zend_Form_FileUpload_Example/lib/Zend/View/Abstract.php on line 786
Essentially, what is happening is that the App_Form_Element_File class that we wrote assigns the $_FILES array to the $value parameter for the form element. On redisplay of the form, the formFile view helper then calls the escape() view helper passing in the $value when rendering the <input> element. The escape() view helper calls htmlspecialchars() which throws the warning about $value not being a string.
*whew!*
What we need is something that's an array when the data is valid, but can also look like a string to htmlspecialchars(). This got me thinking about the SPL and creating an object for the data from the $_FILES array.
Let's call this object App_Form_Element_FileValue and store it in lib/App/Form/Element/FileValue.php:
<?php class App_Form_Element_FileValue extends ArrayObject { public function __toString() { $result = ''; if(isset($this->name)) { $result = $this->name; } return $result; } }
The ArrayObject class is part of the SPL and handily provides a set of functions that enables the object to work with most functions that we like to use with an array including the ability to access the data using array notation. We implement the PHP5 magic function __toString() so that htmlspecialchars() will get a string from the object when it asks for one which nicely knocks that problem on the head.
To integrate it into the code, we need to modify App_Form_Element_File::isValid() from:
public function isValid($value, $context = null) { // for a file upload, the value is not in the POST array, it's in $_FILES $key = $this->getName(); if(null === $value) { if(isset($_FILES[$key])) { $value = $_FILES[$key]; } } // continues...
to
public function isValid($value, $context = null) { // for a file upload, the value is not in the POST array, it's in $_FILES $key = $this->getName(); if(null === $value) { if(isset($_FILES[$key])) { $value = new App_Form_Element_FileValue($_FILES[$key]); } } // continues...
We also need to modify the validator App_Validate_ValidFile::isValid() function as it's rather too rigourous in its checking. We currently check that $value is an array using is_array():
public function isValid($value) { // default value and error is "no file uploaded" $valueString = ''; $error = UPLOAD_ERR_NO_FILE; if(is_array($value) && array_key_exists('error', $value)) { // set the error to the correct value $error = $value['error']; // set the %value% placeholder to the uplaoded filename $valueString = $value['name']; } // continues...
As $value is now an object of type App_Form_Element_FileValue, we need to change the test in the if statement to:
public function isValid($value) { // default value and error is "no file uploaded" $valueString = ''; $error = UPLOAD_ERR_NO_FILE; if((is_array($value) || $value instanceof ArrayObject) && array_key_exists('error', $value)) { // set the error to the correct value $error = $value['error']; // set the %value% placeholder to the uplaoded filename $valueString = $value['name']; } // continues...
Note that we test for an instance of ArrayObject as that is where the functionality of array behaviour is implemented and is more generic in case we need to reuse this code with another object that behaves like an array.
Those are the only changes needed to elegantly remove the error message.
Here's a zip file of this project with the above changes: Zend_Form_FileUpload_Example_Revisited.zip (It includes Zend Framework 1.5.2 which is why it's 3.9MB big).
Test it out and see if it works for you as well as it works for me !
