Re: Using guile's web client

[Nala Ginrut]

I'm afraid it's a real bug.

read-response-body didn't check <eof> before it call bytevector-length. 

But actually, all the data has already been read. When it encounters <eof>, it should return the body immediately. The bug is, it checks bytevector-length first which cause (bytevector-length <eof>).

I didn't realize this bug before, because I read the body by block which always constrains the bytevector length within the range of content-length. 

But I'm not going to send a patch for this bug. Because I've sent another patch to rewrite the whole read-response-body which get rid of this bug already. And it will return the received body data when any error or break happens. The old one didn't do this job.

Here is the thread:

http://lists.gnu.org/archive/html/guile-devel/2012-03/msg00116.html
What do you think?

Regard.

On Thu, Mar 15, 2012 at 8:05 AM, Chris Vine <address@hidden> wrote:

Hi,

I have been playing around with guile-2.0.5's high-level web modules.
In order to see if I understood them, I tried about the simplest thing
I could think of: a GET request to checkip.dyndns.com to obtain my IP
address.

The following code works correctly provided I leave the commented out
code commented out:

(use-modules
 (web uri)
 (web response)
 (rnrs bytevectors)
 (web client))

((lambda()
  (let ((uri (build-uri 'http
                        #:host "checkip.dyndns.com"
                        #:port 80
                        #:path "/")))
    (display uri)
    (newline)
    (let ((r (http-get uri #:keep-alive? #t)))
      (if r
          (begin
            (display r)(newline)
;;           (display (read-response-body r))(newline)
            )
          (begin
            (display "Can't obtain response body")
            (newline)))))))

It outputs:

#<<uri> scheme: http userinfo: #f host: "checkip.dyndns.com" port: 80 path: "/" query: #f fragment: #f>
#<<response> version: (1 . 1) code: 200 reason-phrase: "OK" headers: ((content-type text/html) (server . "DynDNS-CheckIP/1.0") (connection close) (cache-control no-cache) (pragma no-cache) (content-length . 105)) port: #<input-output: socket 6>>

The contents of the response object mirrors the response obtained by
node.js with the equivalent code written in _javascript_, including the
content length, so the response object appears to be correct.  However,
if I try to obtain the response body by uncommenting the call to
read-response-body, I get an error:

Backtrace:
In ice-9/boot-9.scm:
 149: 10 [catch #t #<catch-closure 81e9280> ...]
 157: 9 [#<procedure 81b38c0 ()>]
In unknown file:
  ?: 8 [catch-closure]
In ice-9/boot-9.scm:
 63: 7 [call-with-prompt prompt0 ...]
In ice-9/eval.scm:
 407: 6 [eval # #]
In ice-9/boot-9.scm:
2111: 5 [save-module-excursion #<procedure 81a1060 at ice-9/boot-9.scm:3646:3 ()>]
3653: 4 [#<procedure 81a1060 at ice-9/boot-9.scm:3646:3 ()>]
In unknown file:
  ?: 3 [load-compiled/vm "/home/chris/.cache/guile/ccache/2.0-LE-4-2.0/home/chris/src/scheme/my-ip-test.scm.go"]
In /home/chris/src/scheme/my-ip-test.scm:
 18: 2 [#<procedure 81ffd90 ()>]
In web/response.scm:
 223: 1 [read-response-body #]
In unknown file:
  ?: 0 [bytevector-length #<eof>]

ERROR: In procedure bytevector-length:
ERROR: In procedure scm_c_bytevector_length: Wrong type argument in position 1 (expecting bytevector): #<eof>

The error is in the procedure call to read-response-body.  Is this a
bug in guile-2, or am I doing something wrong?

Chris