At $WORK, I’m looking at a web service built on mod_perl 1 / Apache 1. The service takes XML as input and returns XML as output. So far, so good.
Unfortunately, whilst I was testing with curl, I found something odd:
curl -s -v -T- -H'Content-Type: text/xml;charset=UTF-8' http://localhost/api < input.xml
That -T- says to do a PUT request from stdin. It fails and my code returned “no input”.
But when I did this, things worked:
curl -s -v -Tinput.xml -H'Content-Type: text/xml;charset=UTF-8' http://localhost/api
That reads directly from the file. The only difference between the two requests is that the latter includes a Content-Length header whilst the former has Transfer-Encoding: chunked instead.
This is the code that was reading the request.
my $content;
if ( $r->header_in( 'Content-Type' ) ) {
$r->read( $content, $r->header_in( 'Content-Length' ) );
}
return $content;
So, if there’s no Content-Length, what should we do? My first stop is always the venerable eagle book. There’s a little footnote next to read():
At the time of this writing, HTTP/1.1 requests which do not have a Content-Length header, such as one that uses chunked encoding, are not properly handled by this API.
Marvellous. Now, I had a look around in the source code and noticed a function called new_read(). Unfortunately, that failed to work. It stopped chunked reads, but failed to work for ordinary ones.
I did see a post on the mod_perl mailing list which reckoned you could loop and read all input. But I was unable to get that to work either.
So I just decided to disallow chunked input. That’s fairly easy to do, and HTTP has a special status code for it: 411 Length Required. It’s not ideal, but unless this project gets upgraded to Apache 2 (unlikely, quite frankly), it seems to be the best option.
Jabbering Giraffe 