Writing files to temporary locations

Question

I have a requirement to write a file as part of a PHP script (XML contents with a custom file extension), then once the file has been saved to then attach that to an email I'll be sending using PHP Mailer.

The emailing part is fine but I've never had to write a file with PHP before. The file is only required for the duration of the script and doesn't need to be kept permanently.

How can I write a file to a temporary location?

Do I need to clean up the temporary location when done with the file? If so, how?

Answer 1

To avoid the Write-Read-Delete cycle with an actual file on disk, I would keep all of your temporary "file" data stored in memory using php's built-in php://temp and php://memory IO stream wrappers^docs.

// open a temporary file handle in memory
$tmp_handle = fopen('php://temp', 'r+');
fwrite($tmp_handle, 'my awesome text to be emailed');

// do some more stuff, then when you want the contents of your "file"
rewind($tmp_handle);
$file_contents = stream_get_contents($tmp_handle);

// clean up your temporary storage handle
fclose($tmp_handle);

You never have to write or delete a file to the disk. Also, note the difference between using php://temp and php://memory from the docs on the topic:

php://memory and php://temp are read-write streams that allow temporary data to be stored in a file-like wrapper. The only difference between the two is that php://memory will always store its data in memory, whereas php://temp will use a temporary file once the amount of data stored hits a predefined limit (the default is 2 MB). The location of this temporary file is determined in the same way as the sys_get_temp_dir() function.