PHP input and output stream study notes_PHP tutorial

PHP input and output stream study notes

This article mainly introduces PHP input and output stream study notes. PHP input and output streams are accessed through php://. Allows access to PHP's input and output streams, standard input and output and error descriptors, temporary file streams in memory and disk backup, and filters that can operate other read and write file resources. Friends in need can refer to

PHP input and output streams are accessed through php://, which allows access to PHP's input and output streams, standard input and output, and error descriptors, temporary file streams in memory, disk backup, and other read operations. Filter for writing to file resources.

　php://stdin, php://stdout and php://stderr

　php://stdin, php://stdout and php://stderr allow access to the corresponding input or output streams of the PHP process.

php://input

php://input is a read-only stream that can access the requested raw data. In the case of POST requests, it is best to use php://input instead of $HTTP_RAW_POST_DATA (native post data), because it does not rely on specific php.ini instructions and consumes less memory. For example:

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echo file_get_contents("php://input"); ?>

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echo file_get_contents("php://input"); ?>

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/* 这会以大写字母输出 www.jb51.net 的全部内容 */ readfile("php://filter/read=string.toupper/resource=http://www.jb51.net"); ?>

Result: php://output

php://output is a write-only data stream that allows you to write to the output buffer in the same way as print and echo. 　php://fd 　php://fd allows direct access to the specified file descriptor. For example, php://fd/3 refers to file descriptor 3. 　php://memory and php://temp php://memory and php://temp are data streams similar to file wrappers that allow reading and writing temporary data. The only difference between the two is that php://memory always stores data in memory, while php://temp will store it in a temporary file after the amount of memory reaches a predefined limit (default is 2MB). The temporary file location is determined in the same manner as sys_get_temp_dir(). php://filter php://filter is a meta-wrapper designed for filtering applications when a data stream is opened. This is useful for all-in-one file functions like readfile(), file() and file_get_contents(), where there is no opportunity to apply additional filters before the stream contents are read. The parameters are as follows:

Example as follows: 　?

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<🎜>/* This will output the entire contents of www.jb51.net in uppercase letters */<🎜> <🎜>readfile("php://filter/read=string.toupper/resource=http://www.jb51.net");<🎜> <🎜>?>

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