Re: post leaves out form variables with empty values

At 2:22 PM +0100 6/25/04, Martin Simmons wrote:
> >>>>> On Thu, 24 Jun 2004 23:47:24 -0400, Mark Klein <[email protected]> said:
>
>  Mark> I traced a problem in my server to the following fact: As the example
>  Mark> below will show, if you create a fillout-form which gets some
>  Mark> strings, and the user leaves some fields blank when filling it out,
>  Mark> the query-alist passed to the response function *leaves out* the
>  Mark> variables for which no values were entered, as opposed for example to
>  Mark> including the variables with null strings as their value.
>
>  Mark> (defmethod show-form ((url url:http-form) stream)
>  Mark>    (http:with-successful-response (stream :html)
>  Mark>      (html:with-fillout-form (:post url :stream stream)
>  Mark>        (html:accept-input 'html:string "v1" :stream stream)
>  Mark>        (html:accept-input 'html:string "v2" :stream stream)
>  Mark>        (html:accept-input 'html:submit-button "Submit" :stream stream))))
>
>  Mark> (defmethod get-form ((url url:http-form) stream query-alist)
>  Mark>    (http:with-successful-response (stream :html)
>  Mark>      (write query-alist :stream stream)))
>
>  Mark> (http:export-url #u"/test.html"
>  Mark>                   :html-computed-form
>  Mark>                   :form-function #'show-form
>  Mark>                   :response-function #'get-form)
>
>  Mark> I understand that makes the POST a little smaller, but for my
>  Mark> purposes I want all the form variables to appear in the query-alist.
>  Mark> How can this be done?
>
>It looks CL-HTTP's form decoding code in HTTP::PARSE-FORM-RAW-VALUES is
>written that way.  You can work around it like this, but I'm not sure if that
>is by design:
>
>(html:with-fillout-form (:post url :stream stream
>                                   :ENCODING-TYPE '(:MULTIPART :FORM-DATA))
>  ...)

Indeed, no value is represented as nil by the macro bind-query-values. You can
look at how this code works and default values the way you like.

Consider using the w3p presentation system for higher level and cleaner abstractions.