(PHP 4, PHP 5, PHP 7)
tmpfile — 建立一个临时文件
以读写（w+）模式建立一个具有唯一文件名的临时文件，返回一个文件句柄。
文件会在关闭后（用 fclose()）自动被删除，或当脚本结束后。
详细信息请参考系统手册中的 tmpfile(3) 函数，以及 stdio.h 头文件。
返回一个与 fopen() 所打开返回类似的新文件句柄， 或者在失败时返回 FALSE.
Example #1 tmpfile() 例子
<?php
$temp = tmpfile();
fwrite($temp, "writing to tempfile");
fseek($temp, 0);
echo fread($temp, 1024);
fclose($temp); // this removes the file
?>
以上例程会输出：
writing to tempfile
Since this function may not be working in some environments, here is a simple workaround:
function temporaryFile($name, $content)
{
$file = DIRECTORY_SEPARATOR .
trim(sys_get_temp_dir(), DIRECTORY_SEPARATOR) .
DIRECTORY_SEPARATOR .
ltrim($name, DIRECTORY_SEPARATOR);
file_put_contents($file, $content);
register_shutdown_function(function() use($file) {
unlink($file);
});
return $file;
}
Beware that PHP's tmpfile is not an equivalent of unix' tmpfile.
PHP (at least v. 5.3.17/linux I'm using now) creates a file in /tmp with prefix "php", and deletes that file on fclose or script termination.
So, if you want to be sure that you don't leave garbage even in case of a fatal error, or killed process, you shouldn't rely on this function.
Use the classical method of deleting the file after creation:
<?php
$fn = tempnam ('/tmp', 'some-prefix-');
if ($fn)
{
$f = fopen ($fn, 'w+');
unlink ($fn); // even if fopen failed, because tempnam created the file
if ($f)
{
do_something_with_file_handle ($f);
}
}
?>
No, the fseek() is necessary - after writing to the file, the file pointer (I'll use "file pointer" to refer to the current position in the file, the thing you change with fseek()) is at the end of the file, and reading at the end of the file gives you EOF right away, which manifests itself as an empty upload.
Where you might be getting confused is in some systems' requirement that one seek or flush between reading and writing the same file. fflush() satisfies that prerequisite, but it doesn't do anything about the file pointer, and in this case the file pointer needs moving.
-- Josh
I found this function useful when uploading a file through FTP. One of the files I was uploading was input from a textarea on the previous page, so really there was no "file" to upload, this solved the problem nicely:
<?php
# Upload setup.inc
$fSetup = tmpfile();
fwrite($fSetup,$setup);
fseek($fSetup,0);
if (!ftp_fput($ftp,"inc/setup.inc",$fSetup,FTP_ASCII)) {
echo "<br /><i>Setup file NOT inserted</i><br /><br />";
}
fclose($fSetup);
?>
The $setup variable is the contents of the textarea.
And I'm not sure if you need the fseek($temp,0); in there either, just leave it unless you know it doesn't effect it.