That should improve performance tremendously.
Both ETag and LastModified depend on all files the template rendering
depends on. If any of the depended on files changes, both values will
change as well. That allows us to track whether our cached copy is
still current (and force a refresh if not) and also process IfMatch request
headers and reply with a 304 directly so that we do not even have to
transfer the data if nothing changed and the browser still has it.
Introduced two new configuration settings, server.reverseProxy.prefixHeader and server.reverseProxy.schemeHeader to define the headers to evaluate for prefix and scheme to use respectively, also moved server.baseUrl and server.scheme to server.reverseProxy.fallbackPrefix and server.reverseProxy.fallbackScheme.
Also fixed SockJS URI as generated in index.jinja to include BASE_URL.
Should do what PR #507 intended, but with less code duplication.
Major refactoring of octoprint.server.util (divided into smaller submodules), extended Tornado to allow for request-specific max content lengths, introduced settings parameters to configure maximum upload size, maximum request body size and file suffixes
See #455
