Hi, all. I want to make a custom input port that behaves like one returned from get-pure-port, but, also handles file-position.
Simple use example: (let ([in (get-pure-port/seekable uri)]) (display (read-bytes 16 in)) (file-position in 0) (display (read-bytes 16 in)) ; gets same bytes as above To handle (file-position N) where N isn't already the current position, it abandons and reopens the connection using the HTTP header "Range: bytes=N-" (when servers support it). Subsequent reads from the port get the entity from N onward. Simple, and I have some code that works correctly. But using it requires special open/read/position/close functions. Instead, I want any code that knows how to use open-input-file ports and file-position, to be able to use this transparently. So it doesn't need to know or care if the port is a local file or an HTTP entity. So I need a custom port, right? But of the various callback functions I may provide to make-input-port, I don't see the one I need: A way to set the current position. Gah. I've been through the docs many times and I'm stumped. Any ideas? Thank you. _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
