stream_get_contents

(PHP 5, PHP 7, PHP 8)

stream_get_contents — 读取资源流到一个字符串

说明

stream_get_contents(resource $stream, ?int $length = null, int $offset = -1): string|false

与 file_get_contents() 一样，但是 stream_get_contents() 是对一个已经打开的资源流进行操作，并将其内容写入一个字符串返回。返回的内容取决于 length 字节长度和 offset 指定的起始位置。

参数

stream (resource): 一个资源流（例如 fopen() 操作之后返回的结果）
length (int): 需要读取的最大的字节数。默认为 null（读取全部的缓冲数据）。
offset (int): 在读取数据之前先查找指定的偏移量。如果这个数字是负数，就不进行查找，直接从当前位置开始读取。

返回值

返回一个字符串或者在失败时返回 false.

更新日志

版本	说明
8.0.0	现在 `length` 可以为 null。

示例

示例 #1 stream_get_contents() 例子

<?php

if ($stream = fopen('http://www.example.com', 'r')) {
    // 打印从开始的位置偏移 10 个字节后页面的所有内容
    echo stream_get_contents($stream, -1, 10);

    fclose($stream);
}


if ($stream = fopen('http://www.example.net', 'r')) {
    // 打印前 5 个字节
    echo stream_get_contents($stream, 5);

    fclose($stream);
}

?>

注释

注意: 此函数可安全用于二进制对象。

注意:
当指定一个非 null 的 length 值时，即使实际内容要短得多，该函数也会立即分配一个内部缓冲区，其大小为指定的长度。

参见

fgets() - 从文件指针中读取一行
fread() - 读取文件（可安全用于二进制文件）
fpassthru() - 输出文件指针处的所有剩余数据

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User Contributed Notes 5 notes

down

vasiliy at hotger dot com ¶

11 years ago

It is important to know that stream_get_contents behaves differently with different versions of PHP. Consider the following

<?php

$handle = fopen('file', 'w+'); // truncate + attempt to create
fwrite($handle, '12345'); // file position > 0
rewind($handle); // position = 0
$content = stream_get_contents($handle); // file position = 0 in PHP 5.1.6, file position > 0 in PHP 5.2.17!
fwrite($handle, '6789');
fclose($handle);

/**
 *
 * 'file' content
 * 
 * PHP 5.1.6:
 * 67895
 *
 * PHP 5.2.17:
 * 123456789
 *
 */
?>

As a result, stream_get_contents() affects file position in 5.1, and do not affect file position in 5.2 or better.

down

clarck dot smith at gmail dot com ¶

11 years ago

In that case when stream_get_contents/fread/fgets or other stream reading functions block indefinitely your script because they don't reached the limit of bytes to read use the socket_get_meta_data function to figure out the number of the bytes to read. It returns an array that contains a key named 'unread_bytes' and then pass that number to your favourite stream reading functions second parameter to read from the stream.

Maybe a good workaround to use the stream_select function, and set the socket to non-blocking mode with the use of stream_set_blocking($stream, 0). In this case the socket reading functions work properly.

Cheers, Ervin

down

m rahman ¶

12 years ago

When omitting the parameter $maxlength, any received bytes are stacked up until the underlying stream is not readable anymore, the the function returns that stack in one piece.

down

-2

Mike Shiyan ¶

7 years ago

stream_get_contents() can be used instead of fread() even with local files.

down

-15

divinity76+nospam at gmail dot com ¶

7 years ago

/*
 * problem: stream_get_contents blocks / is very slow.
 * I have tried
 * 1: stream_set_blocking, doesn't make a difference.
 * 2: stream_get_meta_data['unread_bytes'] = ITS BUGGED, ALWAYS SAYS 0.
 * 3: feof(): ALSO EFFING BLOCKING
 * 4: my_stream_get_contents hack... kinda working! :D
 */
function my_stream_get_contents ($handle, $timeout_seconds = 0.5)
{
    $ret = "";
    // feof ALSO BLOCKS:
    // while(!feof($handle)){$ret.=stream_get_contents($handle,1);}
    while (true) {
        $starttime = microtime(true);
        $new = stream_get_contents($handle, 1);
        $endtime = microtime(true);
        if (is_string($new) && strlen($new) >= 1) {
            $ret .= $new;
        }
        $time_used = $endtime - $starttime;
        // var_dump('time_used:',$time_used);
        if (($time_used >= $timeout_seconds) || ! is_string($new) ||
                 (is_string($new) && strlen($new) < 1)) {
            break;
        }
    }
    return $ret;
}

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