Re: [Cppcms-users] working with http::context.

[Artyom <art...@ya...>]

> 
> I've been trying to work with http::context but with no  success.
> 
> I am working with forms. During the validation process, I want  to set some 
> messages to display to the user.
> 
> I have seen  widgets::base_widget::error_message() but this is not what I 
need.
> 
> I want  to:
> 1) be able to set errors for the *whole* form, not a specific  widget.
> 2) be able to set various messages that are valid only within a  specific 
> context (http get/post request).

If entry form fails validation you may just display any message you want
outside widgets system. i.e.

if(request().request_method()=="POST") {
   my_content.my_form.load(context());
   if(!my_content.my_form.validate()) {
      my_content.fail_flag = true;
   }
}


And in template system itself

<% if fail_flag %>
   <strong>FAILED</strong>
<% end %>
<form ... >
<% form as_p my_form %>
</form>


See example of forms. Also you can specify a number of reasons
and add some flag to form you are created.

> 
> If I understand well, I  cannot set those message within my cppcms::application 
>
> namespace, since it  is shared between all processes, regardless of user or 
> sessions (?). Thus a  message intended for one user might be displayed for 
> another user.
> 
> I  could use the user session, but a message intended for one page (form 
> submission() might appear on another tab, as the user browses other pages 
> within the site (race condition?).


I don't understand. What do you mean message? What do you mean shared?
What race condition?

> 
> It appeared to me that the  http::context might be the best place to store 
> temporary messages that I  could retrieve and display at the end of the 
> request.

No, http::context just preservers specific information for single
request/response. You can't change or alter it.

> 
> But I have  tried and failed. I am not too sure if it's possible and how to go 

> about it.  I have tried to add members to the context object. If it's possible 

> to do  so, I did it the wrong  way.

You can't and shouldn't derive from context.

Artyom