[Seaside] anchors behaving like buttons?

[Nevin Pratt]

For what it's worth, and if anybody cares, I rearchitected and 
eliminated this scheme from my test site.

Like a dummy, I didn't realize that this scheme would result in a new 
session being created when the link got clicked on.

Nevin




Nevin Pratt wrote:

>
>
> Derek Brans wrote:
>
>> In Seaside, is there a way to have an anchor tag that will submit a 
>> form and perform an action (behaving just like a button)?
>>
>
> I've got a scheme that seems to work OK:
>
> Suppose you've got a component 'Foo', with launch URL of 
> 'http://localhost/seaside/foo' (or whatever machine and port you 
> choose).  Now, suppose the 'Foo' component has links 'red' and 'green' 
> in the GUI, which you want to use to invoke methods #red and #green on 
> component Foo when the links are clicked on.
>
> 1. Define the URL for the 'red' link to be '/seaside/foo/red', and for 
> the 'green' link to be '/seaside/foo/green'.
>
> 2. Give 'Foo' an instance variable called 'targets', and then create 
> an #initialize method of 'Foo' thus:
>
>   initialize
>       targets _ OrderedCollection new.
>       targets add: #red;
>            add: #green
>
> 3. Give 'Foo' a 'lastTarget' instance variable, which will be used to 
> prevent recursive circularities, as shown later.
>
> 4. Put the following in Foo's #renderContentOn:
>
>   renderContentOn: html
>       | path sel |
>       path _ self session path.
>       sel _ (path copyAfterLast: $/) asLegalSelector asSymbol.
>       (lastTarget ~= sel
>            and: [targets includes: sel])
>        ifTrue: [lastTarget _ sel.
>            ^self perform: sel].
>      { ... the rest of the normal rendering code here ... }
>
> With the above, the 'red' and 'green' links will invoke the #red and 
> #green target methods (respectively) of the component, just like a 
> button does.
>
> You can, if you wish, easily eliminate the need for the 'targets' 
> instance variable by, for example, looking for methods within a 
> certain method category, or for methods that begin (or end) with some 
> common string, or even be more general by replacing 'targets includes: 
> sel' with something like 'self respondsTo: sel', but I think I would 
> prefer to keep strict control over what methods can be invoked via the 
> URL with this scheme.  So, I would use a 'targets' instance variable 
> to explicitly define allowable methods that can be invoked with this 
> scheme.
>
> Nevin
>
>
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