PHP: How to put out text/plain content in UTF-8 with BOM for download?

Question

I need to offer a plain text file for download. The text file needs to be UTF-8 encoded and needs a BOM to be present. I saved my php file as UTF-8 without BOM and send the following headers:

header('HTTP/1.1 200 OK');
header('Content-Type: text/plain; charset=utf-8');
header('Content-Disposition: attachment; filename="test.txt"');

I save the script without BOM because it would interfere with sending the headers. So I tried putting a BOM manually by:

echo chr(239).chr(187).chr(191);

Then I put out my text. Without The manual BOM an editor like Notepad++ will recognize the file to be ANSI encoded, with the supposed manual BOM it will be recognized as UTF-8 but will contain the characters:



at the start. So I assume it is detected to be UTF-8 by means of heuristics and my manual BOM is wrong.

How do I do it right?

EDIT: HEX contents as requested. I simply made the text "SOME TEXT" and I get:

C3 AF C2 BB C2 BF 53 4F 4D 45 20 54 45 58 54

Saving "SOME TEXT" as UTF-8 with BOM yields:

EF BB BF 53 4F 4D 45 20 54 45 58 54

Solution

What you're seeing is the result of interpreting the individual bytes of the BOM as IOS-8859-1 and then encoding the result in UTF-8. As for why this happens, I suspect the chr() function - try using char literals instead, i.e.

echo "\xEF\xBB\xBF";