Question

Here is a code form a PHP+MySQL book I am reading and I am having trouble understanding this code. This code is about checking a file uploaded into a database. (Please excuse any spelling errors if any, I was typing it in)

Q1: How does it know which case to echo? In the whole code, there is no mention of each case.

Q2: Why do they skip case 5?! Or does it not matter which numbers you use(so I can have case 1, case 18, case 2?)

For this statement, can you say if($_FILES[‘userfile’][‘error’]=1) instead of >0? Are they the same thing?

    if($_FILES['userfile']['error']>0)
{
    echo 'Problem: ';
switch($_FILES['userfile']['error'])
{
    case 1: echo 'File exceeded upload_max_filesize';
            break;
    case 2: echo 'File exceeded max_file_size';
            break;
    case 3: echo 'File only partially uploaded';
            break;
    case 4: echo 'No file uploaded';
            break;
    case 6: echo 'Cannot upload file: no temp directory specified';
            break;
    case 7: echo 'Upload failed: Cannot write to disk';
            break;
}
exit;
}

Answer 1

This should help:

UPLOAD_ERR_OK Value: 0; There is no
error, the file uploaded with success.

UPLOAD_ERR_INI_SIZE Value: 1; The
uploaded file exceeds the
upload_max_filesize directive in
php.ini.

UPLOAD_ERR_FORM_SIZE Value: 2; The
uploaded file exceeds the
MAX_FILE_SIZE directive that was
specified in the HTML form.

UPLOAD_ERR_PARTIAL Value: 3; The
uploaded file was only partially
uploaded.

UPLOAD_ERR_NO_FILE Value: 4; No file
was uploaded.

UPLOAD_ERR_NO_TMP_DIR Value: 6;
Missing a temporary folder. Introduced
in PHP 4.3.10 and PHP 5.0.3.

UPLOAD_ERR_CANT_WRITE Value: 7; Failed
to write file to disk. Introduced in
PHP 5.1.0.

UPLOAD_ERR_EXTENSION Value: 8; A PHP
extension stopped the file upload. PHP
does not provide a way to ascertain
which extension caused the file upload
to stop; examining the list of loaded
extensions with phpinfo() may help.
Introduced in PHP 5.2.0.

The gist of it is that when you are handling an uploaded file, you check the error value ($_FILES['userfile']['error']) to see the status of the file. The switch statement just breaks it down by checking the possible error codes that could be present. These are basically "hardwired".