[albatross-users] Exception: set_page() passing wrong number of parameters to page_enter()?

[Dave Cole]

>>>>> "Sheila" == Sheila King <sheila at thinkspot.net> writes:

Sheila> I understand what you are saying here...except that it seems
Sheila> to me that there is an exception. When someone submits a form,
Sheila> and makes a cgi request to my application, then as part of the
Sheila> cgi process, I get to determine the output to the browser. I
Sheila> may well choose to have a particular page of my application be
Sheila> the output of the cgi process. In that case, set_page seems to
Sheila> make plenty of sense to me?

I see where you are coming from.  The problem is that the set_page()
pretends that the server is in control of the transition from one page
to another.

What might make more sense is to do something like this in every page
module.  Place all of the application logic in the display function.
Let a common module check the state of the session and have it force
global behaviour if necessary.

Something as simple as this should do the trick.

  import myapp

  def page_display(ctx):
      if myapp.check_session(ctx):
          ctx.run_template('this-page-template.html')

Then in the myapp module you just need to something like.

  def check_session(ctx):
      if ctx.locals._user:
          return 1
      if ctx.req_equals('login'):
          if user_is_valid(ctx.locals.user, ctx.locals.passwd):
              ctx.locals._user = ctx.locals.user
              ctx.add_session_vars('_user')
              return 1
      ctx.run_template('login.html')
      return 0

Sheila> Although I'm certainly willing to go along with, and
Sheila> understand that, this simply isn't the way the Random page
Sheila> modules work. However, I'm having problems with almost any
Sheila> method I try. Please see my other post to this list tonight,
Sheila> on how the ctx.redirect('name') isn't working so hot for
Sheila> me. Or maybe I'm just confused.

It is certainly easy to get confused with this stuff.

Sheila> I thought I understood that page_display() was what got called
Sheila> when a page was simply requested in the URL, and
Sheila> page_process() was used when a cgi form was submitted. But it
Sheila> doesn't seem to be working that way for me.

It is really up to you where you place your code.  They page_enter(),
page_process(), and page_display() are just convenient hooks in the
Application.run() processing sequence.

    ctx = self.create_context()
    ctx.set_request(req)
    self.load_session(ctx)
    self.load_page(ctx)                 # calls page_enter()
    if self.validate_request(ctx):
        self.merge_request(ctx)
        self.process_request(ctx)       # calls page_process()
    self.display_response(ctx)          # calls page_display()
    self.save_session(ctx)

The sequence is described here:

        http://www.object-craft.com.au/projects/albatross/albatross/fig-presimpexec.html

- Dave

-- 
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