[racket-dev] Racket web server doesn't handle POST requests with 'Transfer-Encoding: chunked' ?
There is nothing going wrong with the supported features of the Web
server. It's just that the Web server doesn't support any
Transfer-Encoding other than the default of no encoding.
Jay
On Fri, Mar 9, 2012 at 1:44 AM, John Clements <clements at brinckerhoff.org> wrote:
> My students are working on an assignment that has them CPS and defunctionalize a small evaluator so that they can ship computations from one compute server to another:
>
> http://www.brinckerhoff.org/clements/csc430-wi12/Assignments/ass7.html
>
> As part of this assignment, some of the students are writing servers in node.js, and one of them drew my attention to what appears to be a small bug in Racket's web server. Specifically, it appears that when a request is made with POST data using the 'Transfer-Encoding: chunked" style, that the result of calling request-post-bytes/raw on the request is #f. I can't tell whether the web server is actually reading the POST data correctly and discarding it when the request is constructed, or actually failing to read the data.
>
> To see this happen, run this racket program:
>
> #lang racket
>
> (require web-server/servlet-env
> web-server/http/xexpr
> web-server/http)
>
> ; the function that handles requests:
> (define (start request)
> (define post-bytes (request-post-data/raw
> request))
> (cond [(bytes? post-bytes) (response/xexpr `(html "yep"))]
> [else (response/xexpr `(html "nope"))]))
>
> ; start serving the 'start' function on port 8054:
> (serve/servlet start
> #:servlet-regexp #px".*"
> #:port 8054
> #:launch-browser? #f)
>
> ... and then ping it with curl:
>
> curl -v -X POST -d "hello" http://localhost:8054 -H 'Transfer-Encoding: chunked'
> * About to connect() to localhost port 8054 (#0)
> * Trying 127.0.0.1... connected
> * Connected to localhost (127.0.0.1) port 8054 (#0)
>> POST / HTTP/1.1
>> User-Agent: curl/7.19.7 (universal-apple-darwin10.0) libcurl/7.19.7 OpenSSL/0.9.8r zlib/1.2.3
>> Host: localhost:8054
>> Accept: */*
>> Transfer-Encoding: chunked
>> Content-Type: application/x-www-form-urlencoded
>>
>> 5
> < HTTP/1.1 200 Okay
> < Date: Fri, 09 Mar 2012 08:41:55 GMT
> < Last-Modified: Fri, 09 Mar 2012 08:41:55 GMT
> < Server: Racket
> < Content-Type: text/html; charset=utf-8
> < Connection: close
> <
> * Closing connection #0
> <html>nope</html>
>
>
> The header lines shown by curl here are exactly what they should be, but the server is getting #f for the post-bytes.
>
> Trying this without the 'Transfer-Encoding: chunked' returns the expected byte-string:
>
> oiseau:~ clements$ curl -v -X POST -d "hello" http://localhost:8054* About to connect() to localhost port 8054 (#0)
> * Trying 127.0.0.1... connected
> * Connected to localhost (127.0.0.1) port 8054 (#0)
>> POST / HTTP/1.1
>> User-Agent: curl/7.19.7 (universal-apple-darwin10.0) libcurl/7.19.7 OpenSSL/0.9.8r zlib/1.2.3
>> Host: localhost:8054
>> Accept: */*
>> Content-Length: 5
>> Content-Type: application/x-www-form-urlencoded
>>
> < HTTP/1.1 200 Okay
> < Date: Fri, 09 Mar 2012 08:43:25 GMT
> < Last-Modified: Fri, 09 Mar 2012 08:43:25 GMT
> < Server: Racket
> < Content-Type: text/html; charset=utf-8
> < Connection: close
> <
> * Closing connection #0
> <html>yep</html>
>
> So, is this a bug, or a known problem, or am I just doing something silly? I spent (more time than I want to admit) poking around in the source tree, but I couldn't find the spot where the request was constructed.
>
> John
>
>
> _________________________
> Racket Developers list:
> http://lists.racket-lang.org/dev
>
--
Jay McCarthy <jay at 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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