(http://www.mail-archive.com/osg-users@lists.openscenegraph.org/msg23098.html)
Background: when you access a file over HTTP, you cannot rely on a file extension being present; instead the file's mime-type is conveyed in the HTTP Content-Type response header. This facility adds a mime-type-to-extension map to the registry to handle this.
There are two new osgDB::Registry functions which are pretty self-explanatory:
void addMimeTypeExtensionMapping( mime-type, extension )
ReaderWriter* getReaderWriterForMimeType( mime-type )
I also added the file osgDB/MimeTypes.cpp which houses a hard-coded list of built-in types. I took the list from here (http://www.webmaster-toolkit.com/mime-types.shtml) and then pared it down to include mostly image and video types, editing them to map to existing plugins where possible.
In addition, I updated the CURL plugin to a) install a set of built-in mime-type mappings, and b) use them to look up an extension in the event that the target filename does not have an extension.
Here is a test case. This URL pulls down a JPEG (without a file extension):
osgviewer --image "http://us.maps3.yimg.com/aerial.maps.yimg.com/ximg?v=1.8&s=256&t=a&r=1&x=0&y=0&z=2"
"
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