作为PHP开发人员，我们不需要担心内存管理。在极少数情况下，我们可能需要走出舒适的界限—例如，当我们尝试在可以创建的最小VPS上为大型项目运行Composer时，或者需要在同样小的服务器上读取大文件时。这是我们将在本教程中讨论的一个问题。 衡量成功 // formatBytes 方法取材于 php.net 文档
memory_get_peak_usage();
function formatBytes($bytes, $precision = 2) {
$units = array("b", "kb", "mb", "gb", "tb");
$bytes = max($bytes, 0);
$pow = floor(($bytes ? log($bytes) : 0) / log(1024));
$pow = min($pow, count($units) - 1);
$bytes /= (1 << (10 * $pow));
return round($bytes, $precision) . " " . $units[$pow];
}我们有什么选择？ 逐行读取文件 // from memory.php
function formatBytes($bytes, $precision = 2) {
$units = array("b", "kb", "mb", "gb", "tb");
$bytes = max($bytes, 0);
$pow = floor(($bytes ? log($bytes) : 0) / log(1024));
$pow = min($pow, count($units) - 1);
$bytes /= (1 << (10 * $pow));
return round($bytes, $precision) . " " . $units[$pow];
}
print formatBytes(memory_get_peak_usage());
// from reading-files-line-by-line-1.php
function readTheFile($path) {
$lines = [];
$handle = fopen($path, "r");
while(!feof($handle)) {
$lines[] = trim(fgets($handle));
}
fclose($handle);
return $lines;
}
readTheFile("shakespeare.txt");
require "memory.php";// from reading-files-line-by-line-2.php
function readTheFile($path) {
$handle = fopen($path, "r");
while(!feof($handle)) {
yield trim(fgets($handle));
}
fclose($handle);
}
readTheFile("shakespeare.txt");
require "memory.php";// from reading-files-line-by-line-3.php
$iterator = readTheFile("shakespeare.txt");
$buffer = "";
foreach ($iterator as $iteration) {
preg_match("/\n{3}/", $buffer, $matches);
if (count($matches)) {
print ".";
$buffer = "";
} else {
$buffer .= $iteration . PHP_EOL;
}
}
require "memory.php";文件之间的管道 // from piping-files-1.php
file_put_contents(
"piping-files-1.txt", file_get_contents("shakespeare.txt")
);
require "memory.php";// from piping-files-2.php
$handle1 = fopen("shakespeare.txt", "r");
$handle2 = fopen("piping-files-2.txt", "w");
stream_copy_to_stream($handle1, $handle2);
fclose($handle1);
fclose($handle2);
require "memory.php";// from piping-files-3.php
file_put_contents(
"piping-files-3.jpeg", file_get_contents(
"https://github.com/assertchris/uploads/raw/master/rick.jpg"
)
);
// ...or write this straight to stdout, if we don't need the memory info
require "memory.php";// from piping-files-4.php
$handle1 = fopen(
"https://github.com/assertchris/uploads/raw/master/rick.jpg", "r"
);
$handle2 = fopen(
"piping-files-4.jpeg", "w"
);
// ...or write this straight to stdout, if we don't need the memory info
stream_copy_to_stream($handle1, $handle2);
fclose($handle1);
fclose($handle2);
require "memory.php";$handle1 = fopen(
"https://github.com/assertchris/uploads/raw/master/rick.jpg", "r"
);
$handle2 = fopen(
"php://stdout", "w"
);
stream_copy_to_stream($handle1, $handle2);
fclose($handle1);
fclose($handle2);
// require "memory.php";其他流 php://stdin只读 php://stderr只写，与php://stdout相似 php://input只读，使我们可以访问原始请求内容 php://output只写，可让我们写入输出缓冲区 php://memory与php://temp(可读写) 是临时存储数据的地方。区别在于数据足够大时php:/// temp就会将数据存储在文件系统中，而php:/// memory将继续存储在内存中直到耗尽。 过滤器 // from filters-1.php
$zip = new ZipArchive();
$filename = "filters-1.zip";
$zip->open($filename, ZipArchive::CREATE);
$zip->addFromString("shakespeare.txt", file_get_contents("shakespeare.txt"));
$zip->close();
require "memory.php";// from filters-2.php
$handle1 = fopen(
"php://filter/zlib.deflate/resource=shakespeare.txt", "r"
);
$handle2 = fopen(
"filters-2.deflated", "w"
);
stream_copy_to_stream($handle1, $handle2);
fclose($handle1);
fclose($handle2);
require "memory.php";// from filters-2.php
file_get_contents(
"php://filter/zlib.inflate/resource=filters-2.deflated"
);自定义流 // from creating-contexts-1.php
$data = join("&", [
"twitter=assertchris",
]);
$headers = join("\r\n", [
"Content-type: application/x-www-form-urlencoded",
"Content-length: " . strlen($data),
]);
$options = [
"http" => [
"method" => "POST",
"header"=> $headers,
"content" => $data,
],
];
$context = stream_content_create($options);
$handle = fopen("https://example.com/register", "r", false, $context);
$response = stream_get_contents($handle);
fclose($handle);创建自定义协议和过滤器 Protocol {
public resource $context;
public __construct ( void )
public __destruct ( void )
public bool dir_closedir ( void )
public bool dir_opendir ( string $path , int $options )
public string dir_readdir ( void )
public bool dir_rewinddir ( void )
public bool mkdir ( string $path , int $mode , int $options )
public bool rename ( string $path_from , string $path_to )
public bool rmdir ( string $path , int $options )
public resource stream_cast ( int $cast_as )
public void stream_close ( void )
public bool stream_eof ( void )
public bool stream_flush ( void )
public bool stream_lock ( int $operation )
public bool stream_metadata ( string $path , int $option , mixed $value )
public bool stream_open ( string $path , string $mode , int $options ,
string &$opened_path )
public string stream_read ( int $count )
public bool stream_seek ( int $offset , int $whence = SEEK_SET )
public bool stream_set_option ( int $option , int $arg1 , int $arg2 )
public array stream_stat ( void )
public int stream_tell ( void )
public bool stream_truncate ( int $new_size )
public int stream_write ( string $data )
public bool unlink ( string $path )
public array url_stat ( string $path , int $flags )
}if (in_array("highlight-names", stream_get_wrappers())) {
stream_wrapper_unregister("highlight-names");
}
stream_wrapper_register("highlight-names", "HighlightNamesProtocol");
$highlighted = file_get_contents("highlight-names://story.txt");Filter {
public $filtername;
public $params
public int filter ( resource $in , resource $out , int &$consumed ,
bool $closing )
public void onClose ( void )
public bool onCreate ( void )
}$handle = fopen("story.txt", "w+");
stream_filter_append($handle, "highlight-names", STREAM_FILTER_READ);总结 CodeAE代码之家 其它相关文章！ 
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发布于：2021-09-13 11:06
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