php if else error with form field - php

Question

My form has a input file type field.
<input type="file" name="file" size="80" value="">
when submitted and this field is empty the file upload part of my php script should be skipped. This does not seem to be happening. What I am getting is the wrong file type message popping. Nothing was populated in the field on the form so why is my if/else statement not being followed? What am I doing wrong?
<?php
// connect to datebase
require "master.db.php";
// this if(empty statement is not working?
// should be checking to see if the form field 'file' is populated if so check file
// type if not skip and update sql database with information in form field 'test'
if(!empty($_FILES))
{
if ((($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg")
|| ($_FILES["file"]["type"] == "image/pjpeg"))
&& ($_FILES["file"]["size"] < 2097152))
{
// code here works - function is to upload the file - not part of my current problem
}
// currently this else statement is displayed regardless of 'file' input
// wrong function for its intended purpose
else
{
// wrong file type
echo "Invalid file <br />";
echo "Tryed to upload: " . $_FILES["file"]["name"] . "<br />";
echo "Type: " . $_FILES["file"]["type"] . "<br />";
echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb Max 2Mb <br />";
echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />";
die;
}
}
else
{
// update other data in mysql database
$sql="UPDATE `characters` SET test='$test' WHERE ID='$id'";
$result=mysql_query($sql);
// if successfully updated mysql.
if($result){
echo "<b>Update successful</b> <br />";
echo "<a href='test.html'>View result</a>";
touch('master.html');
clearstatcache();
}
else
{
echo "Whoops: " . mysql_error(); ;
}
mysql_close();
}
?>

Answer 1

The browser will still send the input value, even though the value is empty. As a consequence, PHP will populate the $_FILES array with something like:
Array
(
[file] => Array
(
[name] =>
[type] =>
[tmp_name] =>
[error] => 4
[size] => 0
)
)
So instead of checking with isset/empty, I guess you should use PHP's native is_uploaded_file method. See this SO post for more info on checking if an optional file input was provided.
I'll try to clarify my answer. The reference I just gave suggests using file_exists and is_uploaded_file. According to the PHP manual only using is_uploaded_file is sufficient. In fact, I can imagine is_uploaded_file looks up the file anyway (so internally already does something like file_exists).
Please note that you really should use the tmp_name-key instead of the name-key. The 'name' key specifies the name of the file on the client's PC, but the tmp_name specifies the name on the server. There are situations when the server renames the file and therefore differs from the name on the users PC.

Answer 2

please be sure to add
enctype="multipart/form-data"
attribute in you form tag . and follow #Martijn guidelines
check the below code, it must work. be sure to customize .
<?php
// connect to datebase
require "master.db.php";
// this if(empty statement is not working?
// should be checking to see if the form field 'file' is populated if so check file
// type if not skip and update sql database with information in form field 'test'
if(!empty($_FILES)) // MEANS form is valid ( have valid file and other data)
{
$sql="UPDATE `characters` SET test='$test' WHERE ID='$id'";
$result=mysql_query($sql);
if (((($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg")
|| ($_FILES["file"]["type"] == "image/pjpeg"))
&& ($_FILES["file"]["size"] < 2097152)) && $result ))
{
// code you need to execute
echo "<b>Update successful</b> <br />";
echo "<a href='test.html'>View result</a>";
touch('master.html');
clearstatcache();
}
else
{
// wrong file type
echo "Invalid file <br />";
echo "Tryed to upload: " . $_FILES["file"]["name"] . "<br />";
echo "Type: " . $_FILES["file"]["type"] . "<br />";
echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb Max 2Mb <br />";
echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />";
die;
}
}
else
{
echo "data is not valid";
}
?>