users@javaserverfaces-spec-public.java.net

[jsr372-experts mirror] [jsr372-experts] Re: Re: Re: improvements to f:websocket and PushContext

From: Josh Juneau <juneau001_at_gmail.com>
Date: Mon, 26 Sep 2016 06:41:02 -0500

+1...I agree. Individuals already understand the way that <f:ajax>
functions, so it makes sense to use it if possible.

Josh Juneau
juneau001_at_gmail.com
http://jj-blogger.blogspot.com
https://www.apress.com/index.php/author/author/view/id/1866


On Mon, Sep 26, 2016 at 5:38 AM, Kito Mann <kito.mann_at_virtua.com> wrote:

> +1 for adding <f:ajax> support to <f:websocket>. I believe PrimeFaces does
> this with <p:socket>, and it's certainly more intuitive than hooking it up
> to <f:commandScript>.
>
> ___
>
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> On Sun, Sep 25, 2016 at 11:55 AM, Bauke Scholtz <balusc_at_gmail.com> wrote:
>
>> Hi,
>>
>> h:commandScript is result of https://java.net/jira/browse/J
>> AVASERVERFACES_SPEC_PUBLIC-613 See also
>> http://arjan-tijms.omnifaces.org/p/jsf-23.html for others.
>>
>> I do understand the h:commandScript limitation in portlet case, but in a
>> portlet app there's also only one JavaScript context.
>>
>> I have to admit that the f:websocket+f:ajax looks more natural. I will
>> try creating a POC on this. I only don't like the idea of turning the
>> f:websocket from TagHandler into UIComponent. It's really kind of view
>> metadata.
>>
>> Cheers, B
>>
>>
>>
>> On Sat, Sep 24, 2016 at 3:53 AM, Leonardo Uribe <leonardo.uribe_at_irian.at>
>> wrote:
>>
>>> Hi
>>>
>>> I see, so this is hidden in the spec. Thanks for mention it.
>>>
>>> I have to say I can see a problem with this structure, and it is related
>>> to the "name" used on the script.
>>>
>>> In JSF each component has it own clientId that is calculated somehow. So
>>> according to the location of the component inside the tree, the clientId is
>>> generated.
>>>
>>> The way how clientId works ensures the component can be relocated to
>>> different parts of the tree and it will still work.
>>>
>>> The problem with a hardcode name is that you lose this property in the
>>> code. If you are in a portlet case, I can see that if the same component is
>>> used twice on different portlets, the page will crash by a duplicate
>>> definition.
>>>
>>> There is a component in tomahawk sandbox that try this and it is called
>>> s:jsCallbackFunction . Remember the component is in sandbox, so in that
>>> sense it is experimental.
>>>
>>> * This component creates a function inside an inline &lt;script&gt; tag,
>>> * with a function that can be referenced later using getFunctionName()
>>> method
>>> * inside this component instance or the EL function
>>> #{s:jsCallbackFunctionName(UIComponent)}.
>>> * <p>
>>> * Inside the function, the following code is added:
>>> * </p>
>>> * <code>
>>> * generatedFunctionNameUsingClientIdAndEventName = function (...
>>> arguments ...){
>>> * ... jsStartContent ...
>>> * ... clientBehavior scripts ...
>>> * ... jsEndContent ...
>>> * }
>>> * </code>
>>> * <p> This is useful in situations where the context where this script
>>> is
>>> * rendered is important, and it is not possible to put the scripts on
>>> static
>>> * javascript files.</p>
>>>
>>> What I mean is with an EL function it is possible to generate the
>>> function name based on the clientId of the component and avoid the problem
>>> h:commandScript has.
>>>
>>> Let me be clear about this: the way how h:commandScript works right now
>>> creates a conflict for portlet case, and I do not want to create another
>>> one after spend a lot of time trying to solve JAVASERVERFACES_SPEC_PUBLIC-79
>>> 0.
>>>
>>> The way how h:commandScript and f:websocket interact should be more
>>> subtle. If f:websocket is a component with an id, it should be possible to
>>> reference it so you could "declare" a h:commandScript to be called for
>>> f:websocket. So, with one f:websocket it should be possible to call many
>>> h:commandScript functions.
>>>
>>> I think we should focus our efforts in create a syntax easy to
>>> understand, that solve the problem of update parts of the view after an
>>> event triggered on the server.
>>>
>>> regards,
>>>
>>> Leonardo Uribe
>>>
>>>
>>> 2016-09-23 16:01 GMT-05:00 Bauke Scholtz <balusc_at_gmail.com>:
>>>
>>>> Hi,
>>>>
>>>> It has already been thought about, it can be combined with
>>>> h:commandScript, also new in JSF 2.3.
>>>>
>>>> <f:websocket ... onmessage="someCommandScript" />
>>>> <h:commandScript name="someCommandScript" action="#{bean.pushed}"
>>>> render="foo" />
>>>>
>>>> The message will transparently be available as request parameters in
>>>> associated bean.
>>>>
>>>> Cheers, B
>>>>
>>>> On Fri, Sep 23, 2016 at 9:22 PM, Leonardo Uribe <
>>>> leonardo.uribe_at_irian.at> wrote:
>>>>
>>>>> Hi
>>>>>
>>>>> I have been thinking about the way how f:websocket / PushContext
>>>>> works, just trying to see what's missing or another way to see this
>>>>> feature, to see if we can make it better.
>>>>>
>>>>> Even if f:websocket behavior is well understood and very flexible the
>>>>> way it is, what bothers me about it is this feature is too javascript
>>>>> specific. What I mean is you always need to write a javascript block to
>>>>> handle the incoming processing.
>>>>>
>>>>> But sometimes what you really want is update a part or just an
>>>>> specific component in the view. In other words, sometimes the web socket is
>>>>> only used as way to notify the view that something has changed on the
>>>>> server and the view needs to be updated somehow.
>>>>>
>>>>> In other words, sometimes the user doesn't want to override onmessage
>>>>> and instead just say update component xxx or yyy.
>>>>>
>>>>> For example, imagine the following syntax:
>>>>>
>>>>> <f:websocket channel="ping">
>>>>> <f:ajax event="update" render="myInfoBox"/>
>>>>> </f:websocket>
>>>>>
>>>>> On the server the update is triggered using this:
>>>>>
>>>>> @Inject
>>>>> @Push(channel="ping")
>>>>> private PushContext push;
>>>>>
>>>>> ....
>>>>>
>>>>> push.send("update");
>>>>>
>>>>> Now, f:websocket looks more like a component that implements
>>>>> ClientBehaviorHolder than a tag, and the "default" onmessage is a method
>>>>> that takes the message and if the event match the message it triggers the
>>>>> related f:ajax script.
>>>>>
>>>>> In html markup, f:websocket should create a html tag with the
>>>>> associated custom events.
>>>>>
>>>>> What do you think guys about it? does it work? is it useful? is it
>>>>> worth?
>>>>>
>>>>> regards,
>>>>>
>>>>> Leonardo Uribe
>>>>>
>>>>>
>>>>>
>>>>
>>>
>>
>