Wow. Thank you very much.
On Tue, Apr 24, 2012 at 4:31 PM, Jay McCarthy wrote:
There was no way to do this, but I just added the 92nd keyword to
serve/servlet to do it:
#:servlet-responder
(λ (url exn)
(response/xexpr
`(html (body "Some other message"))))
allows you to inspect the exception and return a different thing.
(The push will happen shortly.)
Jay
On Mon, Apr 23, 2012 at 3:35 PM, Galler <lzgal...@optonline.net>
wrote:
Description:
the stateless webserver allows a user to generate a stuffer to
manipulate
the encoding of the ANF sent to the client in the URL
For example
(stuffer-chain serialize-stuffer (stuffer-compose base64-stuffer
(HMAC-SHA1-stuffer #"mysupersecretkey")))
will prepend a digest to the base64-encoded ANF, and recompute and
authenticate the digest on receipt.
If either the encoded ANF, or the digest has been altered (i.e.
forged) by
the client, the stuffer correctly throws an error, which is caught by
the
webserver, which sends the following response back to the client:
<some html>
Exception
The application raised an exception with the message:
HMAC-SHA1-stuffer: Signature does not match!
</some html>
Question:
While the behavior is absolutely correct, is there someplace to set a
response if an error occurs with the stuffer? Is the error caught at
the
top-level of the dispatching server and not available for
customization?
If the answer is the latter, its ***not*** critical and probably not
important to implement.
Example code: Once running, alter the url in your browser in any
manner
(character addition, deletion, substitution) to generate the expected
error.
#lang web-server
(require web-server/stuffers)
(provide/contract (start (request? . -> . response?)))
(define (start request)
(phase-1 request))
; phase-1: request -> response
(define (phase-1 request)
(local [(define (response-generator embed/url)
(response/xexpr
`(html
(body (h1 "Phase 1")
(a ((href ,(embed/url phase-2)))
"click me!")))))]
(send/suspend/dispatch response-generator)))
; phase-2: request -> response
(define (phase-2 request)
(display (request-bindings/raw request))
(local [(define (response-generator embed/url)
(response/xexpr
`(html
(body (h1 "Phase 2")
(a ((href ,(embed/url phase-1)))
"click me!")))))]
(send/suspend/dispatch response-generator)))
(require web-server/servlet-env)
(serve/servlet start
#:stateless? #t
#:launch-browser? #t
#:connection-close? #t
#:stuffer (stuffer-chain serialize-stuffer
(stuffer-compose
base64-stuffer (HMAC-SHA1-stuffer #"mysupersecretkey")))
#:quit? #f
#:listen-ip #f
#:servlet-path "/")
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--
Jay McCarthy <j...@cs.byu.edu>
Assistant Professor / Brigham Young University
http://faculty.cs.byu.edu/~jay
"The glory of God is Intelligence" - D&C 93
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