PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

432 Chapter 19 Interacting with the File System and the Server
Figure 19.1 The HTML form used for this file upload has different fields
and field types from those of a normal HTML form.
As you can see, the form has a box where the user can enter a filename or click the
Browse button to browse files available to him locally.We look at how to implement this
form shortly.
After entering a filename, the user can click Send File, and the file will be uploaded
to the server, where a PHP script is waiting for it.
Before we dive into the file uploading example, it is important to note that the
php.ini file has five directives that control how PHP will work with file uploading.These
directives, their default values, and descriptions are shown in Table 19.1.
Table 19.1 File Upload Configuration Settings in php.ini
Directive Description Default Value
file_uploads Controls whether HTTP file uploads are allowed. On
Values are On or Off.
upload_tmp_dir Indicates the directory where uploaded files will NULL
temporarily be stored while they are waiting to
be processed. If this value is not set, the system
default will be used.
upload_max_filesize Controls the maximum allowed size for uploaded 2M
files. If a file is larger than this value, PHP will
write a 0 byte placeholder file instead.
post_max_size Controls the maximum size of POST data that 8M
PHP will accept.This value must be greater than
the value for the upload_max_filesize
directive, since it is the size for all of the post
data, including any files to be uploaded.