Скачать или смотреть Efficiently Delete Files Not Listed in a Dynamic Text File Using PHP

Learn how to create a PHP script that deletes files not matching the names found in a dynamic text file. Get step-by-step guidance and code examples.
---
This video is based on the question https://stackoverflow.com/q/72491860/ asked by the user 'Zythmo' ( https://stackoverflow.com/u/19265201/ ) and on the answer https://stackoverflow.com/a/72491991/ provided by the user 'Barmar' ( https://stackoverflow.com/u/1491895/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: php script to delete file names not matching a dynamic text file

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Delete Files Not Listed in a Dynamic Text File Using PHP

Managing files on a server or local directory can become a chore, especially when dealing with numerous images or documents. If you find yourself needing to delete files that do not match a regularly updated list, PHP provides a robust solution. In this guide, we will look at how to create a PHP script that reads file names from a text file and deletes corresponding files from a specified directory.

The Problem

You have a text file, named images.txt, which is located in the directory /home/users/images.txt. This text file contains a list of JPEG file names, such as:

1.jpeg

12.jpeg

33.jpeg

As this text file is regularly updated with new filenames, you want to use a PHP script to ensure that any files in your images directory (/home/user/images/) that do not match the names in images.txt are deleted.

Understanding the Initial Approach

You might have attempted an initial solution that resembles the following code:

[[See Video to Reveal this Text or Code Snippet]]

However, you might have encountered a few issues with this code. Let's break down the primary problems:

Array Values: The names retrieved from the glob() function include the directory path, but the ones stored in $array do not. This discrepancy leads to the in_array() check failing because the comparison is not done correctly.

File Deletion: The unlink() function is being called with the wrong path, as it concatenates the directory path to the filename already containing the directory path.

A Simplified Solution

To fix the aforementioned issues, we need to ensure that we compare just the base names of the files. Here’s how to properly implement the script:

Step-by-Step Breakdown

Read the Text File: Use the file() function with the FILE_IGNORE_NEW_LINES flag to read the names into an array while ignoring any newline characters.

Get the Directory Path: Define the path to the image directory.

List All Files: Use glob() to list all files in the specified directory.

Compare and Delete: Use a loop to check each file in the directory against the list of names and delete those that are not found.

Here’s the revised code:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Code

file() function: It reads the images.txt directly into an array, where each line corresponds to an element in the array. The FILE_IGNORE_NEW_LINES flag ensures that there are no extraneous newline characters.

basename() function: This function extracts just the filename from the complete file path, allowing for an accurate comparison against the array of image names.

unlink() function: When the script identifies that a file does not match any name in the list, it will execute unlink($file) on the exact path that was retrieved from glob().

Conclusion

By applying the changes outlined above, you can efficiently manage files and keep your directory clean from unwanted files that do not match your specified list. This PHP script provides a simple yet effective solution for automated file management, maintaining an organized structure and aiding in preventing clutter.

Feel free to modify the paths and filenames based on your specific setup, and happy coding!