Uploading files via CakePHP has been covered a few times on Labs. Based on the feedback, it’s safe to assume bridging the gap between file uploads and PHP can be tricky. Usually Cake is ready to lend a helpful hand. Not this time.

If you're finding that executing this:
<?php echo $html->formTag('/' . $params['url']['url'], 'post', array('enctype' => 'multipart/form-data')); ?>
	<?php echo $html->input('Test/title'); ?>
	<?php echo $html->file('Test/file'); ?>
	<?php echo $html->submit('Save'); ?>
</form>

... returns something like this:
$this->data:Array
(
    [Test] => Array
        (
            [title] => Foo
            [file] => 4tmp/phpHGSjDA
        )
)

... instead of something like this:
$this->data:Array
(
    [Test] => Array
        (
            [title] => Foo
            [file] => Array
                (
                    [name] => aeo.jpg
                    [type] => image/jpeg
                    [tmp_name] => /tmp/phppM8tfc
                    [error] => 0
                    [size] => 45471
                )
        )
)

... then you must be as annoyed as I am.

The reason why the file form field is returning the tmp name is because CakePHP expects register_globals is OFF.

Solution One

Turn off register_globals via .htaccess:

#/app/webroot/.htaccess
php_flag register_globals off

Solution Two

Manually write your HTML form fields without using an input array:

-- do this --
<input type="file" name="file" />
-- not this --
<?php echo $html->file('Test/file'); ?> // will output: <input type="file" name="data[Test][test]" />

Solution two is a slight pain in the ass, because now that you’ve eliminated the array within the form input field, you need to do a little extra work in your CakePHP controller. (If there’s a demand, I’ll give some examples.)

Hopefully this’ll clear up Cake’s messhole.