The main function in this script is for the validation of our upload, here we do things like check the file type, and if an image, what it’s dimensions are.
<?php
function validate_upload($the_file) {
global $my_max_file_size, $image_max_width, $image_max_height,$allowed_types,$the_file_type,$registered_types;
$start_error = "n<b>Error:</b>n<ul>";
if ($the_file == "none") { # do we even have a file?
$error .= "n<li>You did not upload anything!</li>";
} else { # check if we are allowed to upload this file_type
if (!in_array($the_file_type,$allowed_types)) {
$error .= "n<li>The file that you uploaded was of a ".
"type that is not allowed, you are only
allowed to upload files of the type:n<ul>";
while ($type = current($allowed_types)) {
$error .= "n<li>" . $registered_types[$type] . " (" . $type . ")</li>";
next($allowed_types);
}
$error .= "n</ul>";
}
if (ereg("image",$the_file_type) && (in_array($the_file_type,$allowed_types))) {
$size = GetImageSize($the_file);
list($foo,$width,$bar,$height) = explode(""",$size[3]);
if ($width > $image_max_width) {
$error .= "n<li>Your image should be no wider than " .
$image_max_width . " Pixels</li>";
}
if ($height > $image_max_height) {
$error .= "n<li>Your image should be no higher than " .
$image_max_height . " Pixels</li>";
}
}
if ($error) {
$error = $start_error . $error . "n</ul>";
return $error;
} else {
return false;
}
}
} # END validate_upload
?>
Notes:
| 1-4: | we start our function off and tell PHP what variables have a global scope (i.e. originated outside this function), this also saves us having to use $GLOBALS[] everywhere. |
| 5: | Start our error message off |
| 6-9: | if there is no file, $the_file is set to ‘none’ so we check if the user actually specified a file to upload |
| 13-21: | Here, our in_array function and the two arrays we built earlier come into play, we loop through the $allowed_types array and see if the PHP set $the_file_type is in there, if it is the script knows that it is allowed to accept this. If it is not allowed, then we use the $registered_types array to give a sensible error message. |
| 23-35: | If the uploaded file is an image, we want to check that it’s dimensions are smaller than our pre-defined maximum values. We use the PHP function getimagesize() to check the file dimensions and build up the error string if it is too big. |
| 37-42: | If we have anything in $error, we finish the string off and return it, else we return false. There that’s the hard work done. |
