[Catalyst] $c->write() buffering?

Daniel J. Luke dluke at geeklair.net
Wed Oct 30 00:51:21 GMT 2013

I've got some legacy CGI code that does a bunch of processing and uses the old hack of $| = 1; print "foo\n"; do_work(); print "foo done\n"; etc. (solution #1 from http://wiki.catalystframework.org/wiki/longcomputations)

While I'll eventually convert it to a job queue, I'd like to create an output-identical implementation first with Catalyst, however it seems like I'm getting output buffering when I don't want it.

As a very simple test, I've set up apache 2.2, mod_fastcgi (FastCgiExternalServer with -flush and without -flush) and a method like this:

sub test: Local {
    my ($self, $c) = @_;

    $c->response->content_type( 'text/plain; charset=utf-8' );

    my $i;
    for($i=1;$i<8;$i++) {
        $c->write("$i: foo bar baz\n");

I see all the data at once in my browser instead of a line every second, and with tcpdump, can see that all of the data is coming back in one packet and not in 8+ smaller packets like I expect. If I make the string that gets passed to write longer, I get several packets, but all at once (and not with each iteration through the for loop).

Am I missing something obvious? Is there some way to get the behavior I'm expecting?

Daniel J. Luke                                                                   
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