add cache for requests

[muescha]

proposal:

data cache setting

a link can have a data tag data-cache which can have true or false

<a href="item/1" data-cache="true">item 1</a>

then the emy library replaces the href link to the appended content

id setting

if you need special id then you can set it with

<a href="item/1" data-cache="true" data-cache-id="item-1">item 1</a>

default data cache setting

you can set a default cache on the body tag like data-cache-default="true"

[remi-grumeau]

As a reminder: https://plus.google.com/108518148617591250391/posts/csEgn2iuioy

I LOVE this idea! I'm actually amazed we never thought about it before...
I know we want this to be a core feature since it's a pretty common scenario when creating a web application. I'm just not sure how we might deal with it.

Please also remind that this is a pure performance debate, the linked file won't be loaded twice tru the network, browser's cache would do its job. What we are talking about here is to make Emy smarter by not overwrite the exact same view(s). If the linked file includes a hundred views, that might be noticeable, but in most cases, it's a pure battery saving / performance improvement (which remain important, specially for mobile devices!).

Thinking about it, i might be a good idea not to deal with this on the link side but on the linked view side. Here is what i have in mind:

• <a> element stays untouched, with href="externals.html like today.
• externals.html contains one or multiple views like today.
• the first view in externals.html is the one Emy navigates to like today

But when Emy loads this externals.html and set its first view as the one to show, Emy checks this view node for a data-cache="true" attribute. If so, it changes the tapped/clicked link href attribute value to #view.id.

I like this mechanism better since it's 100% compatible with existing code, and could be added easily later. It also leaves this to developer's choice since a GET parameter can tell the server to generate external view(s) file with this data-cache attribute or not.
ex 1: externals.php generates <section id="view" data-title="My view" data-cache="true">
ex 2: externals.php?dontcache=1 generates <section id="view" data-title="My view">

Agree too, we might want to make this process default or not. I propose emy.ajaxCacheHandler default as false to match this first process. Changing it to true would then make this for all externally loaded views, except if the loaded view as data-cache="false".

This would actually fit both cases, with just one since attribute.