在PHP中将大文件写入磁盘的最佳方式是什么？ [英] What is the best way to write a large file to disk in PHP?

问题描述

我有一个PHP脚本，偶尔需要将大文件写入磁盘。使用 file_put_contents（），如果文件足够大（在这种情况下大约2 MB），PHP脚本内存不足（PHP致命错误：允许的内存大小＃ ####### bytes exhausted）。我知道我可以增加内存限制，但是这似乎不是一个完整的解决方案，我必须有一个更好的方法，对吗？

<在PHP中写大文件到磁盘的最佳方法是什么？ 您需要一个临时文件，在其中放置源文件的位加上要附加的内容：

  $ sp = fopen（'source' ，'r'）; 
 $ op = fopen（'tempfile'，'w'）; 
 
 while（！feof（$ sp））{
 $ buffer = fread（$ sp，512）; //使用512字节的缓冲区
 fwrite（$ op，$ buffer）; 
} 
 
 //追加新数据
 fwrite（$ op，$ new_data）; 
 
 //关闭句柄
 fclose（$ op）; 
 fclose（$ sp）; 
 
 //使临时文件成为新来源
 rename（'tempfile'，'source'）; 
  

这样， source 不被读入内存。使用cURL时，可以省略设置 CURLOPT_RETURNTRANSFER ，而是添加一个写入临时文件的输出缓冲区：

 函数write_temp（$ buffer）{
 global $ handle; 
 fwrite（$ handle，$ buffer）; 
 return''; //返回EMPTY字符串，所以没有内部缓冲
 
 
 $ handle = fopen（'tempfile'，'w'）; 
 ob_start（'write_temp'）; 
 
 $ curl_handle = curl_init（'http://example.com/'）; 
 curl_setopt（$ curl_handle，CURLOPT_BUFFERSIZE，512）; 
 curl_exec（$ curl_handle）; 
 
 ob_end_clean（）; 
 fclose（$ handle）; 
  

---

好像我总是想念那些显而易见的事物。正如Marc指出的，有 CURLOPT_FILE 可以直接将响应写入磁盘。

I have a PHP script that occasionally needs to write large files to disk. Using file_put_contents(), if the file is large enough (in this case around 2 MB), the PHP script runs out of memory (PHP Fatal error: Allowed memory size of ######## bytes exhausted). I know I could just increase the memory limit, but that doesn't seem like a full solution to me--there has to be a better way, right?

What is the best way to write a large file to disk in PHP?

解决方案

You'll need a temporary file in which you put bits of the source file plus what's to be appended:

$sp = fopen('source', 'r');
$op = fopen('tempfile', 'w');

while (!feof($sp)) {
   $buffer = fread($sp, 512);  // use a buffer of 512 bytes
   fwrite($op, $buffer);
}

// append new data
fwrite($op, $new_data);    

// close handles
fclose($op);
fclose($sp);

// make temporary file the new source
rename('tempfile', 'source');

That way, the whole contents of source aren't read into memory. When using cURL, you might omit setting CURLOPT_RETURNTRANSFER and instead, add an output buffer that writes to a temporary file:

function write_temp($buffer) {
     global $handle;
     fwrite($handle, $buffer);
     return '';   // return EMPTY string, so nothing's internally buffered
}

$handle = fopen('tempfile', 'w');
ob_start('write_temp');

$curl_handle = curl_init('http://example.com/');
curl_setopt($curl_handle, CURLOPT_BUFFERSIZE, 512);
curl_exec($curl_handle);

ob_end_clean();
fclose($handle);

---

It seems as though I always miss the obvious. As pointed out by Marc, there's CURLOPT_FILE to directly write the response to disk.

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