PHP file operation returns the location information of the file (absolute address)

In the previous article "How to quickly know the size, type and permissions of the file in php file operations", we introduced how to obtain the file size, file type and file/directory permissions. There are Friends who need it can learn about it~

The main content of this article is: return the location information of the current file, that is, obtain and return the absolute path of the current file.

So how to get the absolute path of the file? Here are some commonly used methods.

1. Use the realpath() function

We know the name of the executed PHP script, assign it to$filename, and then use realpath ($filename) to get the absolute path of the file (including the file name) and learn the location information of$filename.

The output result is:

It can be seen that of course the file$filenameis in the sub-section of the wamp directory on the c drive In the directory www.

The absolute path returned by the realpath() function contains the file name. If you don’t want it, you can use the dirname() function to remove it.

This is the known part File url to get the absolute path of the specified file; but in practice sometimes we don't know part of the url of the current file, so how to get the absolute path of the file? We can use magic constants (__FILE__,__DIR__) or predefined variables ($_SERVER)

2. Use magic constants__FILE__

Use the__FILE__constant directly to get the absolute path of the current file (including the file name)

The output result is:

Same as above, if you don’t want the file name, you can use the dirname() function to remove it, that is, get the absolute directory information where the current file is located

Calling the dirname() function twice can also obtain the upper directory name of the current file

The output result is:

当前文件所在位置： C:\wamp

3. Use magic constants__DIR__

Use the__DIR__constant directly to get the absolute path of the current file, and it does not include the file name. , equivalent todirname(__FILE__).

The output result is:

当前文件所在位置： C:\wamp\www

4. Use predefined variables$_SERVER

$_SERVERcontains information about the server and execution environment. It is an array containing information such as header, path, and script locations. All items in this array are created by the web server.

We can directly use$_SERVER['SCRIPT_FILENAME']to get the absolute path of the currently executing script

The output result is:

当前文件所在位置： C:/wamp/www/demo.php

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