Unique and temporary file names in PHP?

Question

I need to convert some files to PDF and then attach them to an email. I'm using Pear Mail for the email side of it and that's fine (mostly--still working out some issues) but as part of this I need to create temporary files. Now I could use the tempnam() function but it sounds like it creates a file on the filesystem, which isn't what I want. I just want a name in the temporary file system (using sys_get_temp_dir()) that won't clash with someone else running the same script of the same user invoking the script more than once. Suggestions?

Accepted Answer

I've used uniqid() in the past to generate a unique filename, but not actually create the file.

```
$filename = uniqid(rand(), true) . '.pdf';
```

The first parameter can be anything you want, but I used rand() here to make it even a bit more random. Using a set prefix, you could further avoid collisions with other temp files in the system.

```
$filename = uniqid('MyApp', true) . '.pdf';
```

From there, you just create the file. If all else fails, put it in a while loop and keep generating it until you get one that works.

```
while (true) {
 $filename = uniqid('MyApp', true) . '.pdf';
 if (!file_exists(sys_get_temp_dir() . $filename)) break;
}
```

Unique and temporary file names in PHP?

Solution

Problem