gtfs zip occasionally broken?

[bennlich]

I can't figure out how to reproduce this, but it looks like the gtfs zip download occasionally breaks, giving the error:

Error: cannot open file: /Users/bennlich/Documents/NodePractice/santafe-autobus/data/santa-fe-trails_20120504_1700.zip error: Not a zip archive

When this happens, trying to open the archive from the finder also fails.

At first I was able to reproduce the error by deleting the entire data folder (as opposed to only its contents) and restarting the server, but now everything's working as expected.