2011/2/22 Danny Yoo <[email protected]>: > On Tue, Feb 22, 2011 at 12:51 PM, Jay McCarthy <[email protected]> wrote: >> The Web Server will kill connections after a relatively short timeout. >> You'll get an exception when you finally try to use the connection. >> This isn't very nice for COMET. You'll have to reset the timeout on >> the connection manually. > > > Two comments: > > 1. Is output-response from web-server/http/response documented? I > searched and couldn't find it. It seems a critical function for > writing dispatchers.
It is not documented. I imagined people would just throw next-dispatcher and drop to a lifted procedure (dispatch-lift) or their servlet. > > 2. If a user cancels an http request (say, by pressing the stop > button on the browser), is that observable from the web-server side of > things? You can't tell the difference between that and the connection closing for any other reason. Jay > > > I have something like this now, but unfortunately, it's not handling > the scenario from question 2 correctly: > > ;;;;;;;;;;;;;;;;;;; > #lang racket > > ;; Comet demonstration > > (require web-server/web-server > web-server/http/bindings > web-server/http/response > web-server/http/response-structs) > > (define ch (make-channel)) > > (void > (thread (lambda () > > (define (my-dispatcher conn req) > (cond [(exists-binding? 'comet (request-bindings req)) > (handle-comet conn req)] > [else > (handle-default conn req)])) > (serve #:dispatch my-dispatcher #:port 8080)))) > > > (define (handle-comet conn req) > (let ([v (sync ch)]) > (with-handlers ([exn:fail? (lambda (exn) > (printf "exn: ~s\n" exn) > (thread (lambda () (channel-put ch v))))]) > (output-response conn > (response/full 200 #"Okay" > (current-seconds) > #"text/plain; charset=utf-8" > empty > (list #"" (string->bytes/utf-8 > (format "~s" v)))))))) > > (define (handle-default conn req) > (output-response conn '(html (body (p "hello world"))))) > > (define (send-to-client v) > (channel-put ch v)) > -- Jay McCarthy <[email protected]> Assistant Professor / Brigham Young University http://faculty.cs.byu.edu/~jay "The glory of God is Intelligence" - D&C 93 _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
