How to use compression and decompression functions in PHP

PHP, as a popular programming language, provides many functions for processing files and data. These include functions for compressing and decompressing files. These functions allow developers to easily compress and decompress data in PHP, thereby reducing file size and improving transfer efficiency. This article will introduce how to use compression and decompression functions in PHP.

1. Compressed files

In PHP, you can use the functions provided by the zlib extension to compress files. To use these functions, you need to ensure that the zlib extension is installed and enabled in PHP.

1. Installation of zlib extension

To install the zlib extension, you can use the command in the Linux system:

sudo apt-get install php-zip

In Windows systems, you can edit the php.ini file and cancel the comment mark in front of the following line:

;extension=php_zip.dll

2. Start compressing the file

After installing the zlib extension, you can use the following functions to compress files:

• gzwrite(): Write data to the opened gzip format file;
• gzopen(): Open a gzip format file;
• gzencode(): Compress data in gzip format.

Here is a simple example showing how to compress a file into gzip format:

$file = 'example.txt';
$outfile = 'example.txt.gz';
$fileContents = file_get_contents($file);
$gz = gzopen($outfile, 'w9');
gzwrite($gz, $fileContents) ;
gzclose($gz);
?>

In the above example, the file_get_contents() function is used to read data from the file, and the gzopen() function is used to open a compressed file . Use the gzwrite() function to write data to the compressed file, and use the gzclose() function to close the file.

2. Decompress files

In PHP, you can use the functions provided by the zlib extension to decompress files. To use these functions, you need to ensure that the zlib extension is installed and enabled in PHP.

1. Start decompressing the file

After installing the zlib extension, you can use the following function to decompress the file:

• gzread(): Read the opened gzip format file;
• gzopen(): open the gzip format file;
• gzdecode(): decompress the gzip format data.

The following is a simple example showing how to decompress a file in gzip format:

$infile = 'example.txt.gz' ;
$outfile = 'example.txt';
$gz = gzopen($infile, 'r');
$out = fopen($outfile, 'w');
while ( $string = gzread($gz, 4096)) {

fwrite($out, $string, strlen($string));

}
gzclose($gz);
fclose($out);
?>

In the above example, a compressed file is opened using the gzopen() function and the contents of the file are read using the gzread() function. Then, use the fwrite() function to write the data to the file. Finally, use the gzclose() function and fclose() function to close the file.

3. Conclusion

It is very simple to use compression and decompression functions in PHP. Just install the zlib extension and use the corresponding functions. These functions can help developers reduce file size and improve transfer efficiency.

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