I am new to this forum. This is my first question.
I have a nginx-server + fcgiwrapper set up to run Programs on user request (no PHP).
For testing I have a simple bash script, which displays the environment variables and sets two cookies, a second bash-script prints "Hello World" as text/plain and another bash-script prints "Hello World" as text/html.
Another Program written in C is supposed to read Text from stdin, parse it and print Text based in the input to stdout, which the should be displayed as text/plain in the requesting webbrowser. (the requesting browser needs to use POST).
However sometimes it displays the returned text as "text/plain" (which it should do), but sometimes the browser wants to download the returned text, as if it was "application/octet-stream".
But, if I test the C-Program in a prepared Environment
Environment Variables:
CONTENT_LENGTH=30
REQUEST_METHOD=POST
HTTP_COOKIE=NAME=TEST; ID=200
it works every time, shows no errors and at the beginning it prints:
Content-type: text/plain (plus two newlines)
I have found that depending on the contents length it sometimes works and sometimes doesn't. (This only happens when the program is started through a webbrowser.) In Firefox, using the dev-tools, I could see that the answers Content-type was
application/octet-stream
and if I save it, it turns out to be a text file which contains the text that should have been displayed in the browser directly. What am I doing wrong?
Edit: I have already searched for similar problems with no success + all other things work perfectly + This also happens with different browsers (epiphany, lynx, internet explorer on Windows)
Through trial and error (with curl + firefox-dev-tools) I have found, that the character
0x11
in combination with:
Content-type: text/plain
makes nginx deliver Content-type: application/octet-stream .
I don't know why this happens, but i found that the C-program produces the error, because it prints 0x11 or ^Q or dc1.
This phenomenom also happens with files containing this character.