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File Upload

table of Contents

File Upload

principle

Written form

$ _FILES variable Detailed

Move the temporary files to the target location

Multiple file uploads

Data structure in the form of multi-file upload $ _FILES variable

Traversal of the multi-file read and process information

Upload file follow-up questions

principle

File uploads: files from the user's local computer saved to the server computer where the directory specified by the transmission (web forms).

1, increasing the file upload form: a server browser requests an HTML script (include file upload form)

2, the user selects a file from the local (click the upload box (button))

3, the user clicks the Upload button: the file will be transferred to the server via the Internet,

4, server operating system will save the file to a temporary directory: Temporary files are saved in a format (Windows under tmp)

5, the server script to work: to determine the file is valid

6, the server script will effectively move the file from the temporary directory to the specified directory (complete)

Written form

1) method attribute: a file upload form submission must be POST

2) entype attributes: form Form Properties, mainly standardized form of data encoding.

3) upload form: file Form

$ _FILES variable Detailed

In PHP, there is a predefined variable $ _FILES is designed to store the user to upload the file.

Test: If there is no enctype attribute, upload files look like?

1) name: files on the user (browser) computer name actually exists (to retain the actual suffix)

2) tmp_name: upload files to a temporary path to the server operating system saved (PHP actually used to later use)

3) type: MIME type (Multipurpose Internet Mail Extensions), is used in the computer client identify the file type (determined software)

4) error: file upload code that tells the application software (PHP) files what's wrong reception process (post-judgment according to the code PHP files)

5) size: file size (PHP late to determine whether or not according to the actual needs of the reservation)

Move the temporary files to the target location

After the saved file is uploaded to the $ _FILES, then the information is in the form of access to the file $ _FILES [ 'form name attribute value'] [ 'element information']

1）判断是否为上传文件：is_uploaded_file()