Re: Error when referencing http_parameters

Jan - I've had this issue, and now Phillip is finding it awkward. Is there some way to make references to http_params idempotic?




________________________________
 From: Phillip Soltan <[email protected]>
To: Anne Ogborn <[email protected]> 
Sent: Thursday, December 19, 2013 4:25 PM
Subject: Re: [SWIPL] Error when referencing http_parameters
 


Hi Anne,

That would explain the problem.  When I change the form request to a GET the problem goes away.
I would consider it more than a wart though.  I need to reuse predicates to avoid cutting-and-pasting the same code in different places and this makes it more difficult.  I'll have to think of something.

Thanks for you help!

Phillip Soltan



On Thu, Dec 19, 2013 at 3:40 PM, Anne Ogborn <[email protected]> wrote:

yes - with POST the query string type data gets passed in the body of the request. 
> the post data gets read the first time http_parameters gets called, and the second time it hangs.
>
>
>It's a bit of a wart. 8c/  
>
>
>change your request to a GET temporarily and see if it clears up. If so, that's your problem. 
>
>
>
>________________________________
> From: Phillip Soltan <[email protected]>
>To: [email protected] 
>Sent: Thursday, December 19, 2013 2:18 PM
>Subject: [SWIPL] Error when referencing http_parameters
> 
>
>Hello,
>
>I recently discovered that an HTTP package was added to SWI Prolog and I
>thought this was the perfect solution for me.  Between the documentation,
>reading the module code and stepping through the modules with the debugger,
>I think it is going to be suitable for a web site I'm building.
>
>I've run into a problem and I'm wondering if someone could help.  I've
>created a predicate that handles showing the login page:
>
>login_page(Request)
 :-
>html_set_options([dialect('html5')]),
>(http_session_data(lang(_));http_session_asserta(lang('en'))),
>(memberchk(method(post),Request) ->
>http_parameters(Request,
>                        [ email(Email_value, [default('empty')]),
>                          password(Pass_value, [default('empty')])
>                        ]);
>        Email_value = '[email protected]',
>        Pass_value = 'password'
>    ),
>reply_html_page(
>[title('Login Page')],
>           ........ snip .......
>
>It gets called directly from the handler when there is a GET to the login
>url (http://localhost/login) and also gets called from the login action
>predicate:
>
>% handle case of invalid email address
>login_action_page(Request) :-
>http_parameters(Request,
>                        [ email(Email, [default('empty')]),
>                          password(_Pass, [default('empty')])
>                        ]),
>    \+epassword(Email,_),
>    asserta(login_error('unrecognized email')),
>login_page(Request).
>
>
>The login_action_page handles the POST request when the submit button is
>pressed.  It calls login_page to show the login page again showing which
>field has erroneous data.
>
>The POST request times out and return the
 error:
>
>*copy_stream_data/3: Timeout in read from <stream>(0x888eaa0)*
>
>
>This is the result of the second call to http_parameters.  I guess my
>questions are:
>
>Why?  Is there some reason I can't call http_parameters twice with the same
>request?
>
>
>Thank you in advance,
>
>Phillip Soltan
>email: [email protected]
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