I don't think it matters much what server you use for this type of service. We've been using FastCGI for two fairly large JSON services (11K lines) for a year with no problems. Warp and Snap are also sufficient. Is speed a big concern? Otherwise the iterators will be a bit pointless. I'm with you on forgeting about worrying about the server for this type of service and calling it a day.

I'm fairly ignorant of how FastCGI works and only slightly less ignorant about Warp after reading a paper on it by Michael Snoyman, but concurrent connections is a concern. I haven't been able to test the app with a large dataset but the algorithm is something along the lines of O^2 complexity so some requests may take much longer than others. One of my concerns then is that the server should be able to handle concurrent connections well and not let any long-running requests starve/block the others. If FastCGI forks off one process per connection, that would likely be a lot of overhead for the simple case.

One thing I can say is that my app as it exists now must parse the entire request body JSON before it starts acting on it. I hope that clears things up.

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Michael Xavier
http://www.michaelxavier.net