Re: Operate upon POST request with Guile webserver

[Gentoo Arch <gentoocore@firemail.cc>]

Hi Daniel,

Thanks a lot, that worked! I also can print debugging output to server 
log and do other useful stuff.

I totally forgot about (begin); procedural habit I guess.

On 8/19/22 14:00, Daniel Meißner wrote:
> Hi,
>
> Am 17. August 2022 13:50:46 MESZ schrieb Gentoo Arch <gentoocore@firemail.cc>:
>> Hi,
>>
>> I'd like to ask for your advice.
>>
>> I'm trying to figure out how Guile webserver works to develop a simple BBS  and I'm kinda stuck with POST request.
>>
>> My Guile script generates a form on any path and the form sends to "/post" path, where I can easily render content sent by the form.
>>
>> (define (show-page request body)
>>    (if (equal? (get-path request) ; get-path is my other function to retrieve the path
>>                '("post"))
>>        (values '((content-type . (text/plain)))
>>                 body)
>>        (respond ; literally a respond template from webserver doc
>>         `((h1 "Oops!")
>>       (p (@ (id "test")) "The path: " ,(get-path request))
>>       (form (@ (method "POST") (action "/post"))
>>             (label (@ (for "test")) "Content: ")
>>             (input (@ (id "test") (type "text") (name "content")))
>>             (input (@ (type "submit") (value "Submit"))))))))
>>
>> But I would like to operate upon the content the form sends like web apps usually do: insert it in the database or simply write to file. So my question is how I can proceed with something like that:
>>
>> (define tf (open-file "test-file.txt" "a"))
>>
>> (define (show-page request body)
>>    (if (equal? (get-path request)
>>                '("post"))
>>        ((values '((content-type . (text/plain)))
>>                body)
>>         (display body tf)); I'd like to write/append body to the file, but it does nothing
>>        (respond
>>         `((h1 "Oops!")
>>       (p (@ (id "test")) "The path: " ,(get-path request))
>>       (form (@ (method "POST") (action "/post"))
>>             (label (@ (for "test")) "Content: ")
>>             (input (@ (id "test") (type "text") (name "content")))
>>             (input (@ (type "submit") (value "Submit"))))))))
>>
>> If I remove (values), it does write to a file (with a complaint in webserver output), but I'd also like to add some kind of redirect from "/post" page after the script has written stuff to file and I can't use two functions per response.
>>
>> Could you please advise how I can achieve this functionality?
> I think you probably want to replace the true-branch of your `if' form with
>
> (begin
>    (display body tf)
>    (values '((content-type . (text/plain)) body))
>
> It is important that the handler returns two values, so the `values' form must come last in the sequence. These two return values make up the response.
>
> Best
> Daniel
>