[drakma-devel] GET :PARAMETERS added again during redirects

[Eugene Ossintsev]

I use DRAKMA 1.0, Clozure CL 1.4-dev (Ubuntu Linux x86). According to
the DRAKMA documentation, parameters is an alist of name/value pairs
(the car and the cdr each being a string) which denotes the parameters
which are added to the query part of the URI or (in the case of a POST
request) comprise the request body.

In my example QUOTES1 sends a GET request passing the request
parameters in the URI, and QUOTES2 uses the :PARAMETERS instead. The
results, unfortunately, are not the same.


(defun quotes1 ()
  (multiple-value-bind (body code)
      (drakma:http-request
"http://finance.yahoo.com/d/quotes.csv?s=XIC.TO&f=sxl1d1t1")
    (when (= code 200)
      (split-sequence:split-sequence #\, body))))

("\"XIC.TO\"" "\"Toronto\"" "18.03" "\"10/9/2009\"" "\"3:59pm\" ^M
")                 <=== It's fine :-)


(defun quotes2 ()
  (multiple-value-bind (body code)
      (drakma:http-request "http://finance.yahoo.com/d/quotes.csv"
                           :method :get
                           :parameters '(("s" . "XIC.TO")
                                         ("f" . "sxl1d1t1")))
    (when (= code 200)
      (split-sequence:split-sequence #\, body))))

("\"XIC.TO\"" "\"Toronto\"" "18.03" "\"10/9/2009\"" "\"3:59pm\""
"\"XIC.TO\"" "\"XIC.TO\"" "\"XIC.TO\"" "\"Toronto\"" "18.03"
"\"10/9/2009\"" "\"3:59pm\" ^M
\"XIC.TO\"" "\"Toronto\"" "18.03" "\"10/9/2009\"" "\"3:59pm\""
"\"XIC.TO\"" "\"XIC.TO\"" "\"XIC.TO\"" "\"Toronto\"" "18.03"
"\"10/9/2009\"" "\"3:59pm\" ^M
")                 <=== It's a mess :-(


TRACE DRAKMA:HTTP-REQUEST shows that in case of redirects of GET
requests the parameters from :PARAMETERS are added again to the URI.
Thus, the same parameters may be added again and again, giving
unpredictable results.

0> Calling (DRAKMA:HTTP-REQUEST
"http://finance.yahoo.com/d/quotes.csv" :PARAMETERS (("s" . "XIC.TO")
("f" . "sxl1d1t1")))
 1> Calling (DRAKMA:HTTP-REQUEST #<URI
http://download.finance.yahoo.com/d/quotes.csv?s=XIC.TO&f=sxl1d1t1>
:REDIRECT 4 :STREAM NIL :ADDITIONAL-HEADERS NIL :PARAMETERS (("s" .
"XIC.TO") ("f" . "sxl1d1t1")))
 <1 DRAKMA:HTTP-REQUEST returned 7 values :
 <1      #(34 88 73 67 46 84 79 34 44 34 84 111 114 111 110 116 111 34
44 49 55 46 57 56 44 34 49 48 ..........
 <1      200
 <1      ((:DATE . "Wed, 14 Oct 2009 05:00:51 GMT") (:P3P .
"policyref=\"http://p3p.yahoo.com/w3c/p3p.xml\", CP=\"CAO DSP COR CUR
ADM DEV TAI PSA PSD IVAi IVDi CONi TELo OTPi OUR DELi SAMi OTRi UNRi
PUBi IND PHY ONL UNI PUR FIN COM NAV INT DEM CNT STA POL HEA PRE
GOV\"") (:CACHE-CONTROL . "private") (:CONNECTION . "close")
(:TRANSFER-ENCODING . "chunked") (:CONTENT-TYPE .
"application/octet-stream"))
 <1      #<URI http://download.finance.yahoo.com/d/quotes.csv?s=XIC.TO&f=sxl1d1t1&s=XIC.TO&f=sxl1d1t1>
 <1      #<FLEXI-STREAMS:FLEXI-IO-STREAM #x15616B76>
 <1      T
 <1      "OK"


Is it what may be expected from such usage of :PARAMETERS in GET
requests? If not, is it worth fixing it?


- Eugene