This module enables you to transparently read and write gzip (.gz) compressed files, through versions of most of the filesystem functions which work with gzip-compressed files (and uncompressed files, too, but not with sockets).
注: Version 4.0.4 introduced a fopen-wrapper for .gz-files, so that you can use a special 'zlib:' URL to access compressed files transparently using the normal f*() file access functions if you prepend the filename or path with a 'zlib:' prefix when calling fopen().
In version 4.3.0, this special prefix has been changed to 'zlib://' to prevent ambiguities with filenames containing ':'.
This feature requires a C runtime library that provides the fopencookie() function. To my current knowledge the GNU libc is the only library that provides this feature.
This module uses the functions of zlib by Jean-loup Gailly and Mark Adler. You have to use a zlib version >= 1.0.9 with this module.
Zlib support in PHP is not enabled by default. You will need to configure PHP --with-zlib[=DIR]
PHP 的 Windows 版本已经内置该扩展模块的支持。无需加载任何附加扩展库即可使用这些函数。
注: Builtin support for zlib on Windows is available with PHP 4.3.0.
这些函数的行为受 php.ini 的影响。
The zlib extension offers the option to transparently compress your pages on-the-fly, if the requesting browser supports this. Therefore there are three options in the configuration file php.ini.
表格 1. Zlib Configuration Options
|zlib.output_compression||"0"||PHP_INI_ALL||Available since PHP 4.0.5.|
|zlib.output_compression_level||"-1"||PHP_INI_ALL||Available since PHP 4.3.0.|
|zlib.output_handler||""||PHP_INI_ALL||Available since PHP 4.3.0.|
Whether to transparently compress pages. If this option is set to "On" in php.ini or the Apache configuration, pages are compressed if the browser sends an "Accept-Encoding: gzip" or "deflate" header. "Content-Encoding: gzip" (respectively "deflate") and "Vary: Accept-Encoding" headers are added to the output.
This option also accepts integer values instead of boolean "On"/"Off", using this you can set the output buffer size (default is 4KB).
注: output_handler must be empty if this is set 'On' ! Instead you must use zlib.output_handler.
Compression level used for transparent output compression.
You cannot specify additional output handlers if zlib.output_compression is activated here. This setting does the same as output_handler but in a different order.
This example opens a temporary file and writes a test string to it, then it prints out the content of this file twice.
例子 1. Small Zlib Example