[drakma-devel] Drakma : Problem saving file

[lam at tuxfamily.org]

hello,
i make some test with drakma and i have a problem with http-request :

CL-USER> (with-open-file (os (format nil "/tmp/~A.png" "tttt")
                                   :direction :output
                                   :if-exists :supersede
                                   :element-type 'unsigned-byte)
               (multiple-value-bind (body-stream status-code headers uri
    stream must-close)
                 (drakma:http-request
                  "http://stats-dev/cgi-bin/view_image.cgi?filename=/tmp/sms_5Avkjm.png"
                  :want-stream t :force-binary t :content-length t)
                 (declare (ignore headers uri stream must-close))
                 (when (= status-code 200)
                   (format t "Type ~A~%" (type-of body-stream))
                   (loop for c = (read-byte body-stream nil)
                      until (null c)
                      do (progn
                           (format t "Write ~%")
                           (write-byte c os)))
                   (close body-stream))))
Type FLEXI-IO-STREAM
T

after i try with another image :

    CL-USER> (with-open-file (os (format nil "/tmp/~A.png" "tttt")
                                   :direction :output
                                   :if-exists :supersede
                                   :element-type 'unsigned-byte)
               (multiple-value-bind (body-stream status-code headers uri
    stream must-close)
                 (drakma:http-request
                  "http://www.google.com/images/logo_sm.gif"
                  :want-stream t :force-binary t :content-length t)
                 (declare (ignore headers uri stream must-close))
                 (when (= status-code 200)
                   (format t "Type ~A~%" (type-of body-stream))
                   (loop for c = (read-byte body-stream nil)
                      until (null c)
                      do (progn
                           (format t "Write ~%")
                           (write-byte c os)))
                   (close body-stream))))
    Type FLEXI-IO-STREAM
    Write
    Write
    Write
    Write
    Write
    Write
    [...]
    Write
    Write
    T


and the file /tmp/tttt.png contains the google's logo. With the first
    request, the file is empty.

    Here it is the differents between the 2 requests :

    CL-USER> (drakma:http-request
                  "http://stats-dev/cgi-bin/view_image.cgi?filename=/tmp/sms_5Avkjm.png"
                  :want-stream t)
    #<FLEXI-STREAMS:FLEXI-IO-STREAM {B0F1BF9}>
    200
    ((:DATE . "Tue, 05 Dec 2006 18:09:17 GMT")
     (:SERVER
      . "Apache/1.3.34 (Debian) PHP/4.4.4-6 mod_jk/1.2.18 mod_ssl/2.8.25
    OpenSSL/0.9.8c mod_perl/1.29")
     (:CONNECTION . "close") (:TRANSFER-ENCODING . "chunked")
     (:CONTENT-TYPE . "image/png"))
    #<URI
http://stats-dev/cgi-bin/view_image.cgi?filename=/tmp/sms_5Avkjm.png>
    #<FLEXI-STREAMS:FLEXI-IO-STREAM {B0F1BF9}>
    T


    and :


    CL-USER> (drakma:http-request
              "http://www.google.com/images/logo_sm.gif"
              :want-stream t)
    #<FLEXI-STREAMS:FLEXI-IO-STREAM {B13C631}>
    200
    ((:CONTENT-TYPE . "image/gif")
     (:LAST-MODIFIED . "Wed, 07 Jun 2006 19:38:24 GMT")
     (:EXPIRES . "Sun, 17 Jan 2038 19:14:07 GMT") (:SERVER . "GWS/2.1")
     (:CONTENT-LENGTH . "4707") (:DATE . "Tue, 05 Dec 2006 18:10:07 GMT"))
    #<URI http://www.google.com/images/logo_sm.gif>
    #<FLEXI-STREAMS:FLEXI-IO-STREAM {B13C631}>
    T

    i see that in the request which have a problem content-length is not
sended.
    but i don't really understand why the first image is empty.

    thanks if someone understand my problem.