PHP: php:// - Manual (original) (raw)

php:// — Accessing various I/O streams

Description

PHP provides a number of miscellaneous I/O streams that allow access to PHP's own input and output streams, the standard input, output and error file descriptors, in-memory and disk-backed temporary file streams, and filters that can manipulate other file resources as they are read from and written to.

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

php://stdin, php://stdout andphp://stderr allow direct access to the corresponding input or output stream of the PHP process. The stream references a duplicate file descriptor, so if you open php://stdin and later close it, you close only your copy of the descriptor-the actual stream referenced by [STDIN](reserved.constants.php#constant.stdin) is unaffected. It is recommended that you simply use the constants [STDIN](reserved.constants.php#constant.stdin),[STDOUT](reserved.constants.php#constant.stdout) and [STDERR](reserved.constants.php#constant.stderr) instead of manually opening streams using these wrappers.

php://stdin is read-only, whereasphp://stdout and php://stderr are write-only.

php://input

php://input is a read-only stream that allows you to read raw data from the request body.php://input is not available in POST requests withenctype="multipart/form-data" ifenable_post_data_reading option is enabled.

php://output

php://output is a write-only stream that allows you to write to the output buffer mechanism in the same way asprint and echo.

php://fd

php://fd allows direct access to the given file descriptor. For example, php://fd/3 refers to file descriptor 3.

php://memory and php://temp

php://memory and php://temp are read-write streams that allow temporary data to be stored in a file-like wrapper. One difference between the two is thatphp://memory will always store its data in memory, whereas php://temp will use a temporary file once the amount of data stored hits a predefined limit (the default is 2 MB). The location of this temporary file is determined in the same way as thesys_get_temp_dir() function.

The memory limit of php://temp can be controlled by appending /maxmemory:NN, where NN is the maximum amount of data to keep in memory before using a temporary file, in bytes.

Caution

Some PHP extensions may require a standard IO stream, and may attempt to cast a given stream to a standard IO stream. This cast can fail for memory streams as it requires the Cfopencookie() function to be available. This C function is not available on Windows.

php://filter

php://filter is a kind of meta-wrapper designed to permit the application of filters to a stream at the time of opening. This is useful with all-in-one file functions such as readfile(),file(), and file_get_contents() where there is otherwise no opportunity to apply a filter to the stream prior the contents being read.

The php://filter target takes the following parameters as part of its path. Multiple filter chains can be specified on one path. Please refer to the examples for specifics on using these parameters.

php://filter parameters

Options

Wrapper Summary (for php://filter, refer to the summary of the wrapper being filtered)

Examples

Example #1 php://temp/maxmemory

This optional parameter allows setting the memory limit beforephp://temp starts using a temporary file.

<?php
// Set the limit to 5 MB.
$fiveMBs = 5 * 1024 * 1024; <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>f</mi><mi>p</mi><mo>=</mo><mi>f</mi><mi>o</mi><mi>p</mi><mi>e</mi><mi>n</mi><mo stretchy="false">(</mo><mi mathvariant="normal">&quot;</mi><mi>p</mi><mi>h</mi><mi>p</mi><mo>:</mo><mi mathvariant="normal">/</mi><mi mathvariant="normal">/</mi><mi>t</mi><mi>e</mi><mi>m</mi><mi>p</mi><mi mathvariant="normal">/</mi><mi>m</mi><mi>a</mi><mi>x</mi><mi>m</mi><mi>e</mi><mi>m</mi><mi>o</mi><mi>r</mi><mi>y</mi><mo>:</mo></mrow><annotation encoding="application/x-tex">fp = fopen(&quot;php://temp/maxmemory:</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.8889em;vertical-align:-0.1944em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">p</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">=</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord mathnormal" style="margin-right:0.10764em;">f</span><span class="mord mathnormal">o</span><span class="mord mathnormal">p</span><span class="mord mathnormal">e</span><span class="mord mathnormal">n</span><span class="mopen">(</span><span class="mord">&quot;</span><span class="mord mathnormal">p</span><span class="mord mathnormal">h</span><span class="mord mathnormal">p</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">:</span><span class="mspace" style="margin-right:0.2778em;"></span></span><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mord">//</span><span class="mord mathnormal">t</span><span class="mord mathnormal">e</span><span class="mord mathnormal">m</span><span class="mord mathnormal">p</span><span class="mord">/</span><span class="mord mathnormal">ma</span><span class="mord mathnormal">x</span><span class="mord mathnormal">m</span><span class="mord mathnormal">e</span><span class="mord mathnormal">m</span><span class="mord mathnormal" style="margin-right:0.03588em;">ory</span><span class="mspace" style="margin-right:0.2778em;"></span><span class="mrel">:</span></span></span></span>fiveMBs", 'r+');

fputs($fp, "hello\n");

// Read what we have written.
rewind($fp);
echo stream_get_contents($fp);
?>

Example #2 php://filter/resource=

This parameter must be located at the end of your php://filter specification and should point to the stream which you want filtered.

<?php
/* This is equivalent to simply:
  readfile("http://www.example.com");
  since no filters are actually specified */

readfile("php://filter/resource=http://www.example.com");
?>

Example #3 php://filter/read=

This parameter takes one or more filternames separated by the pipe character |.

<?php
/* This will output the contents of
  www.example.com entirely in uppercase */
readfile("php://filter/read=string.toupper/resource=http://www.example.com");

/* This will do the same as above
  but will also ROT13 encode it */
readfile("php://filter/read=string.toupper|string.rot13/resource=http://www.example.com");
?>

Example #4 php://filter/write=

This parameter takes one or more filternames separated by the pipe character |.

<?php
/* This will filter the string "Hello World"
  through the rot13 filter, then write to
  example.txt in the current directory */
file_put_contents("php://filter/write=string.rot13/resource=example.txt","Hello World");
?>

Example #5 php://memory and php://temp are not reusable

php://memory and php://temp are not reusable, i.e. after the streams have been closed there is no way to refer to them again.

<?php
file_put_contents('php://memory', 'PHP');
echo file_get_contents('php://memory'); // prints nothing

Example #6 php://input to read JSON data from the request body

This example demonstrates how to read raw JSON data from POST, PUT and PATCH requests using php://input.

<?php
$input = file_get_contents("php://input");
$json_array = json_decode(
  json: $input,
  associative: true,
  flags: JSON_THROW_ON_ERROR
);

echo "Received JSON data: ";
print_r($json_array);
?>

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