CC'ing laszlo-dev:
Here's the relevant bit for my application, from
http://state-machine.org/categories.lzx. This lives on the LZX canvas:
<attribute name="appstate" type="string"/>
<view name="appstatemanager">
<attribute name="appstate" value="{}"/>
<attribute name="callbacks" value="{}"/>
<attribute name="ignorecallback" value="false"/>
<method name="setState" args="name, value">
if (value == null) value = '';
this.appstate[name] = value;
var o = '';
for (var i in this.appstate) {
o += i + '^' + this.appstate[i] + '~';
}
this.ignorecallback = true;
Lz.setCanvasAttribute('appstate', o, true);
</method>
<method name="refreshState" event="onappstate" reference="canvas">
if (this.ignorecallback == true) {
this.ignorecallback = false;
return;
}
if (canvas['appstate'] == null) return;
var a = canvas.appstate.split('~');
for (var i = 0; i < a.length; i++) {
if (a[i].length == 0) continue;
var arg = a[i].split('^');
var methodname = arg[0];
this.appstate[methodname] = arg[1];
//if ($debug) Debug.write('refreshState', methodname, arg);
if (this.callbacks[methodname])
this.callbacks[methodname](arg[1]);
}
</method>
<method name="registerCallback" args="name, value">
this.callbacks[name] = value;
</method>
</view>
This sort of serialization/deserialization really should be a platform
feature. For that, I intended to use a URL-safe JSON encoding scheme
called RISON - http://mjtemplate.org/examples/rison.html
In any case, this should give you a template to get the
encoding/deconding you want.
Let me know if you have questions!
Jes Lefcourt wrote:
Hi Max,
Do you, perchance, have an example of the first option? All of the
examples I've seen match the second option. However, the second option
doesn't allow the deep linking that you talked about (since #4 doesn't
mean anything when you come in from another page).
Thanks!
- Jes
On Oct 16, 2007, at 8:11 PM, Max Carlson wrote:
This is fine, but I'd definitely prefer you use the built-in mechanism
so we can find bugs and improve it to suit your needs!
If you call Lz.setCanvasAttribute() with the third argument set to
true (in dhtml or Flash) it will create a hash object for you and
ensure the state gets pushed onto the history stack.
From there, you can register for events on that canvas attribute to
receive data. This is the mechanism I use on
http://state-machine.org/. As you browse through the visualization,
the complete application state is serialized to a single string value
that's stored on the hash mark, e.g.
http://state-machine.org/#_lzappstate=s%5ES8MI00281%7CS6MO00305%7E
This provides deep linking and bookmarkability.
LzHistory can do all this for you in a much more elegant and
unobtrusive way. Instead of hanging all application state off of a
single string, LzHistory can store an arbitrary amount of application
state that's offset by a counter. In this case, '#0' is all that's
appended to the URL - much prettier. Provided persistence is turned
on, application state will live across reloads.
Both of these are options built into the system. Please try to use
them and let me know if you run into issues and have ideas for
improvements!
[EMAIL PROTECTED] wrote:
Hi Max,
I couldn't find test/history/history.lzx. I didn't want to wait
until you were back on to continue working, though, so I got it going
by creating my own anchor string structure and directly calling
Lz.history.set(). I then added the reading hooks in by adding my own
Lz.setCanvasAttribute line to the JS _historyEvent function.
Everything seems to work very well, with one exception. This is a
minor issue, but I believe I've found a bug in Firefox. It's
demonstrated by the following HTML:
----
<html>
<body>
<script type="text/javascript">
var val = 0;
</script>
<input type="button" onclick="val++; top.location.hash = '#'
+ val;" value="Advance"></input>
</body>
</html>
-----
If you go to this page, and start clicking on the button, then the
value of the anchor increments, as you expect it to. However, if you
manually change the value of the anchor and hit enter, then the
button no longer advances the anchor value. It's like it's stuck. I
verified that this does not happen in IE.
I was going to file a bug with Firefox, but their process for filing
is a bit too long for my taste. I thought you might want to know
about it, though.
- Jes
Ah yes, this isn't a bug - it's a feature :P. Once a user manually
changes the URL in Firefox, Javascript no longer has access to change
it for security reasons. Some browsers do this, others don't...
On Mon, Oct 15, 2007 at 10:10 PM, Max Carlson wrote:
Hi Jes,
Are you looking to do this in Flash? If so, LzHistory already has
what you need - see this in test/history/history.lzx:
<method event="oninit">
LzHistory.setPersist(true);
</method>
You can also use setCanvasAttribute(name, value, true) to set a
canvas attribute to an arbitrary string via an anchor - this works
across runtimes. If neither of these does what you want I'd like to
work together to get you something that does.
Let me know if you have more questions!
Jes Lefcourt wrote:
Thank you, gentlemen! Fantastic service, as always (and I'll
imagine that you're smiling)!
Max: You might be interested in what we're working on... As part
of the project for XXXX, we're modifying LzHistory so that it's
preserved when you leave the page and come back. So, in summary,
the plan is to change it to use a meaningful value for the anchor
instead of the incremented numbers and to create a handler to
convert variables and values to and from anchor strings. Do you
have any advice? Would the platform be interested in the code when
we're done?
Thanks again!
- Jes
On Oct 15, 2007, at 12:05 PM, John Sundman wrote:
Documentation issue filed as
http://www.openlaszlo.org/jira/browse/LPP-4899
(This applies to documentation, not to any free-standing examples
in the examples directory.)
Thanks,
jrs
On Oct 15, 2007, at 11:55 AM, Max Carlson wrote:
embed-compressed.js is what's used by default. embed.js and
vbembed.js are legacy versions left behind for backward
compatibility.
If you're looking for the source of embed-compressed.js, see
lps/includes/source/embed-library.js for the top-level include.
[EMAIL PROTECTED] wrote:
Hello,
Can someone please explain to me the difference between the
different embed scripts in OL 4? There are embed.js,
embed-compressed.js and vbembed.js. embed.js is what all of the
examples use, but the LzHistory support is only in
embed-compressed.js. Also, embed-compressed.js certainly isn't
a compressed version of embed.js, since it's more than twice the
size and with additional functionality.
Finally, if embed-compressed.js is the most complete version
(which it appears to be), is there an uncompressed version of it
somewhere that has tabbing and is generally readable?
Thanks!
- Jes
--
Regards,
Max Carlson
OpenLaszlo.org
--
Regards,
Max Carlson
OpenLaszlo.org
--
Regards,
Max Carlson
OpenLaszlo.org
