[Seaside] Seaside login - a write up

[Avi Bryant]

On Sep 27, 2004, at 10:43 PM, Roger Whitney wrote:

> ---------- What not to do
>
> One might be tempted to avoid the overhead of using a session by doing:
>
> MyComponent>> renderContentOn: html
> 	user := self call: SeasideLogin new.
> 	Rest of your renderContentOn: code.
>
> At least in the VW version of Seaside, doing this makes the 
> application unstable, so don’t do it.

Yes, sending #call: from a render method is a bad idea.  Definitely 
don't do that.  Usually, the desire to do that is a sign that you 
should be using a WATask.  A task is a safe way to have the render 
phase of a component trigger calls to other components.  Components 
that are subclasses of WATask don't ever render anything - as soon as 
they are about to be rendered, their #go callback gets triggered 
instead.

If you use a task, you don't need a custom session subclass for either 
of your two techniques.  In the case of using SeasideLogin, your Task 
would look like this:

MyTask>>go
	user := self call: SeasideLogin new.
	self call: MyComponent new

In the case of using the builtin HTTP auth, it would look like this:

MyTask>>go
	self session authenticateWith: CS683Authenticator during:
		[self call: MyComponent new]

In both cases you simply need to set MyTask, instead of MyComponent, as 
the root component of the application.

Avi