Django returns blank pages

Suddenly I started getting开发者_JAVA百科 HTTP 200 with zero byte content for every request handled by Django.

This problem has appeared in past, too, and seemed to randomly disappear.

I see a debug view when I make syntax errors, but if the code executes fine, I get a blank page.

I tried resetting Apache, moving project directory, removing .pyc's—what next?

This mistake scores highest on stupidness * impact measure among all I've ever made.

I upload changes to our server via SFTP, and I got a short connection outage during last round of changes. Apparently, it happened exactly the moment I was uploading base.html, the base template for them all. The file was overwritten as zero byte empty file, and Django was correctly serving it.

Two things I've learned:

• to never trust SFTP clients;
• to inspect diff with HEAD when a problem occurs.

This just happened to me again. (I guess I'm lucky!)
I haven't found the cause but was able to recover by stopping and then starting Apache:

sudo apache2ctl stop
sudo apache2ctl start

Apparently, this isn't the same as restarting (sudo apache2ctl start) which didn't help at all.