stream_copy_to_stream

(PHP 5, PHP 7, PHP 8)

stream_copy_to_stream — Copies data from one stream to another

说明

function stream_copy_to_stream(
    resource $from,
    resource $to,
    ?int $length = null,
    int $offset = 0
): int|false

Makes a copy of up to length bytes of data from from to to, starting at the current position in from, or at offset if it is greater than 0. If length is null, all remaining content in from will be copied.

参数

from: The source stream
to: The destination stream
length: Maximum bytes to copy. By default all bytes left are copied.
offset: If greater than 0, the position in from, counted from the start of the stream, at which to start copying: from is first moved to that position, as with fseek() and SEEK_SET. If 0 (the default) or negative, no seek is performed and copying starts at the current position in from.

返回值

Returns the total count of bytes copied, 或者在失败时返回 false.

更新日志

版本	说明
8.0.0	`length` is now nullable.

示例

示例 #1 A stream_copy_to_stream() example

<?php
$src = fopen('http://www.example.com', 'r');
$dest1 = fopen('first1k.txt', 'w');
$dest2 = fopen('remainder.txt', 'w');

echo stream_copy_to_stream($src, $dest1, 1024) . " bytes copied to first1k.txt\n";
echo stream_copy_to_stream($src, $dest2) . " bytes copied to remainder.txt\n";

?>

注释

注意:
When from is a socket stream in blocking mode, copying stops as soon as no data is received within the stream timeout, even if the end of the stream has not been reached. false may then be returned, even though the data read until then has already been written to to. This timeout defaults to default_socket_timeout and can be changed with stream_set_timeout().

参见

copy() - 拷贝文件

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down

divinity76 at gmail dot com ¶

7 years ago

note that this function does not actually use sendfile() on linux systems (at least not in PHP 7.2.12)

down

none at noone dot com ¶

19 years ago

stream_copy_to_stream almost copies a stream...

$objInputStream = fopen("php://input", "rb");
$objTempStream = fopen("php://temp", "w+b");
stream_copy_to_stream($objInputStream, $objTempStream);

That code will copy a stream but it will also move the stream pointers to EOF.  This is fine if you plan on rewinding the temp stream but good luck rewinding the input stream.

rewind($objTempStream);
rewind($objInputStream);

So as you can see this is stream copy or stream move depending on what kind of stream you are working with, and because there are no peaking functions your effed if you need to read from an input stream in multiple classes that are unrelated.

down

anon at example dot com ¶

10 months ago

Passing 0 as $offset does not rewind the stream. Any offset that's zero or less is just ignored. It's a bit inconsistent with stream_get_contents().