[Twisted-web] Resource.child_()

[Wilfredo Sánchez Vega]

   I'm wondering how married we are to the child_ method registration  
implementation for children in Resource.  it's a bit of a strange way  
to do this... it means that valid URI characters can't be used, for  
one thing.

   Additionally, File doesn't use this mechanism at all, and instead  
puts registered children into a dictionary instead.  That  
implementation is more flexible, but not compatible with the  
documented API in its Resource superclass, which says that putChild 
("foo", x) means child_foo() = x.

   Furthermore, Resource also allows for a childFactory() method to  
be a source for children, and that API is also ignored by File.  My  
feeling is that Resource should be doing none of this at all, and  
that there should be two subclasses (ie.  
FunkyChildMethodDispatchingResource and FactoryResource) which do one  
or the other, if we need these mechanisms to be provided by web2 in a  
generic class at all.

   Going to the extreme, the notion of resources having children at  
all is a strange thing to build into a generic HTTP resource.   
Resources that contain other resources (collections) are specified in  
WebDAV, but (intentionally) not in HTTP.  A lot of implementations  
map URIs with slashes in them to a hierarchical back-end (eg. a file  
system), but that's not inherrent in HTTP; /foo and /foo/ can be  
different and completely unrelated resources.  That leads me to think  
that locateChild() itself shouldn't be an IResource thing, but  
perhaps that's too pedantic given common usage of URI paths.

	-wsv