Therefore, if
you browse to a file named vacation.png and upload it via the form, this variable
will be assigned the value vacation.png.
??? $_FILES['userfile']['size']: This variable specifies the size, in bytes, of the
file uploaded from the client machine. Therefore, in the case of the vacation.png
file, this variable could plausibly be assigned a value such as 5253, or roughly 5KB.
??? $_FILES['userfile']['tmp_name']: This variable specifies the temporary name
assigned to the file once it has been uploaded to the server. This is the name of
the file assigned to it while stored in the temporary directory (specified by the
PHP directive upload_tmp_dir).
??? $_FILES['userfile']['type']: This variable specifies the MIME type of the file
uploaded from the client machine. Therefore, in the case of the vacation.png
image file, this variable would be assigned the value image/png. If a PDF were
uploaded, the value application/pdf would be assigned. Because this variable
sometimes produces unexpected results, you should explicitly verify it yourself
from within the script.
PHP??™s File-Upload Functions
In addition to the host of file-handling functions made available via PHP??™s file
system library (see Chapter 10 for more information), PHP offers two functions
specifically intended to aid in the file-upload process, is_uploaded_file() and
move_uploaded_file(). This section introduces each function.
Pages:
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472