at least on Windows 10 with php 7.3.7, and Debian Linux with php 7.4.2,
the mode is not (as the documentation states) 'w+' , it is 'w+b'
(an important distinction when working on Windows systems)
(PHP 4, PHP 5, PHP 7, PHP 8)
tmpfile — 建立一个临时文件
以读写（w+）模式创建一个具有唯一文件名的临时文件，然后返回该文件的句柄。
文件在关闭后（例如，调用 fclose() 或 tmpfile() 返回的文件句柄已无引用的情况）或脚本运行结束后，会自动删除。
如果脚本运行被意外终止，可能不会删除该临时文件。
返回新文件的句柄，类似于 fopen() 返回的文件句柄， 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
at least on Windows 10 with php 7.3.7, and Debian Linux with php 7.4.2,
the mode is not (as the documentation states) 'w+' , it is 'w+b'
(an important distinction when working on Windows systems)
To get tmpfile contents:
<?php
$tmpfile = tmpfile();
$tmpfile_path = stream_get_meta_data($tmpfile)['uri'];
// ... write to tmpfile ...
$tmpfile_content = file_get_contents($tmpfile_path);
?>
Perhaps not the best way for production code, but good enough for logging or a quick var_dump() debug run.
To get the underlying file path of a tmpfile file pointer:
<?php
$file = tmpfile();
$path = stream_get_meta_data($file)['uri']; // eg: /tmp/phpFx0513a
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.