[racket] tcp-read handlers

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- From this code extracted from the context of where the exn took place,
this does seem to be the case:

;; url.rkt
(define (purify-http-port in-port)
  (define-values (in-pipe out-pipe) (make-pipe))
  (thread
   (λ ()
     (define status (http-read-status in-port))
     (define chunked? (http-read-headers in-port))
     (http-pipe-data chunked? in-port out-pipe)
     (close-input-port in-port)))
  in-pipe)

Thanks for the exn tip btw.

On 01/18/2014 02:04 PM, Matthew Flatt wrote:
> The `exn?` predicate would catch all exceptions from the base 
> libraries.[*]
> 
> I think the problem may be that the underlying TCP port is read in
> a separate decoding thread, and so the exception and printing
> happens in that thread. If I'm right, then that seems like a flaw
> in our implementation of decoding.
> 
> [*] To avoid interfering with the `exn:break?` exceptions triggered
> by Ctl-C, you almost always want `exn:fail?` instead of just
> `exn?`.
> 
> At Sat, 18 Jan 2014 09:50:15 -0200, Eduardo Bellani wrote: Is there
> a way to install a handler for the tcp-error exception? I have a
> function like this
> 
> (define (get-page link-url (max-tries 5)) (let loop ([current-try
> 0]) (with-handlers ([exn? (? (e) (if (> current-try max-tries) 
> (error 'get-page "failed because it exceeded ~a tries" max-tries) 
> (begin (sleep 2) (loop (add1 current-try)))))]) (get-pure-port
> link-url))))
> 
> that I'm using to crawl some data, but sometimes it's printing:
> 
> tcp-read: error reading system error: Connection reset by peer;
> errno=104 context...: /usr/racket/collects/net/url.rkt:392:3
> 
> Thanks for the attention.
> 
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