[Seaside] Rendering Callbacks during an Ajax callback

[Johan Brichau]

Hi Joachim,

I’m a bit confused why you are rendering in this way in your callback method. 
Why are you doing this differently than in any other Seaside rendering method?

Since you are instantiating a new builder, it is going to create it’s own rendercontext, hence it’s own registry for callbacks.
I have not deeply investigated the result of your code snippet, but this seems to me why you are seeing that callback numbers are restarted.

Now, if you re-render list-item with a callback on it, Seaside will indeed need to register a new callback. The memory overhead should be limited to the registry dictionary entry and a WASeasideCallback instance, however, since the block and it’s lexical context object will already exist before rendering. So… I would not worry about memory overhead.

If you are doing this because you are doing hand-written ajax calls: what I tend to do is generate a jQuery-Seaside ajax callback and assign this to a Javascript variable, which I can use from the hand-written JS. Of course, there’s variations on this other than global-variable assignment but that’s all Javascript fiddling.

So, before I try to dig deeper in your problem: why is this method not called: "changeSomeStuffOnTheServerAndRedrawOn: html” :) ?

Johan


> On 10 Feb 2017, at 17:26, jtuchel at objektfabrik.de wrote:
> 
> Dear Seasiders,
> I must bee overlooking something obvious. 
> I want to redraw a listItem in and unorderedList (it is a boostrap .list-item .row, but that doesn't really matter) in an Ajax callback. 
> This listItem contains normal anchors with callbacks. 
> The ajax call is initiated in a javascript function, not rendered by Seaside. This call to ajax does the following;
> 
> 
> $.ajax( ... ).done(function(result) {
>         row.replaceWith(result);});
> 
>     
> where row is a jquery that contains the listItem. The rerendering works very well and all seems good.
> 
> Except for one little detail: the callbacks rendered in the AJax callback are re-numbered from 1 and once you click on oneof the re-rendered link it is a nice surprise what method might get called on the server. I guess I am messing with the _s and _k parameters in my caööback method.
> 
> So here is my callback method which answers the re-rendered listItem/row:
> 
> 
> changeSomeStuffOnTheServerAndRedraw
> 
>     | rahmenElementId fields req betrag planElement conv wrapper ctx contKey row resp |
> 
> 
>         ctx := self requestContext.
>         req := ctx request.
>         resp := ctx response.
>         fields := req fields.
> 
>         "Some boring business stuff which works like a charm, including finding the right business objects, changing them, commits in Glorp and whatnot"
>         "Re-render the row"
>         row := self findTheListItemComponentForRerendering.
> 
>         resp
>             status: 200;
>             contentType: (WAMimeType textHtml charset: ctx handler charSet);
>             nextPutAll: (
>                 (self rendererClass builder)
> "**->"              actionUrl: (ctx session actionUrlForKey: contKey);   "I also tried leaving this out --> even worse"
>                     fullDocument: false;
>                     render: [:html |
>                         html render: row ])
> 
> I think the problem is either the fact that I shouldn't be using the requestContext of the Ajax callback, or the actionUrl: part is wrong.
> The rows not re-rendered still work like a charm.
> 
> 
> You can see in the attached picture that both a not-re-rendered row and the re-rendered row point to the same 's anchors point to the same url with identical _s and _k parameters, but thesecond one is the re-rendered and its callback number is 1 instead of 51, which it had before re-rendering:
> 
> <ifioakbcdojcdbmm.png>
> 
> If I use the URL and replace the 1 with 51, The correct callback is being called, the initial callback is still registered. 
> I wouldn't mind if the re-render registered another Callback, even if that means I waste memory, but it seems I am registering the new callbacks in some registry that's new for the ajax callback.... (I am confused)
> 
> Any hints? Ideas? How can I make sure the anchors in that redrawn listItem find their callback blocks on the server?
> 
> 
> Thank you in advance
> 
> Joachim 
>  
> 
> 
> 
> 
> 
> -- 
> -----------------------------------------------------------------------
> Objektfabrik Joachim Tuchel          mailto:jtuchel at objektfabrik.de <mailto:jtuchel at objektfabrik.de>
> Fliederweg 1                         http://www.objektfabrik.de <http://www.objektfabrik.de/>
> D-71640 Ludwigsburg                  http://joachimtuchel.wordpress.com <http://joachimtuchel.wordpress.com/>
> Telefon: +49 7141 56 10 86 0         Fax: +49 7141 56 10 86 1
> 
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