在脚本中设置 application/json 内容类型不起作用

Question

I have a fairly simple php script on my site. It basically greps a file for some text, then send it to the user as json. On my local system, it works fine. On my Reclaim Hosting site, the content-type comes out text/html. Here are the relevant lines:

header('Content-Type: application/json');
$json_output = json_decode(implode("\n", $matches[0]));
print_r(json_encode($json_output));

I set my php.ini to:

output_buffering = Off

php 7.3.6. Apache 2.4.46

Answer 1

I was messing around so much with the file that I'm not quite sure of the entire sequence, but the error log showed a header already sent, as @Barmar suggested. In the end the format was UTF-8 BOM and the BOM was doing it.

So the working output lines are now:

header('Content-Type: application/json');
echo implode("\n", $matches[0]);

Thanks for the help.

EDIT: To be clear a BOM in the script file triggers this.