To the best of my knowledge, we (from the client side) have no control
over the browser's cache. Internally we do something very like you
do, attaching a random query string to 'break' the browser's cache
(that is, to make the browser fetch a new copy).
Your image _server_ has to be the one to tell IE not to cache your
images using the cache-control headers:
http://support.microsoft.com/kb/234067
On 2008-01-30, at 07:32 EST, Michael Kroll wrote:
Hi all,
today I was trying to fix a problem with my image distribution app
while it consumes lots of memory.
In my case I need to display lots (500+) images per patient study
which are loaded from a webserver.
I'm still in the dhtml boat and I'm currently testing my app agains
build 7833 of OL4.1.x.
After some search in the OL Forum and in the book OL in Action I
tried to use setSource() with its additional cache
parameter without luck. My app does is using a timestamp inside the
image url to ensure that the image is not loaded from the browsers
cache. The images are not loaded from the browsers cache, but they
are stored there :-(
I tried to specify setSource("myUrl", "none") without luck. The
memory usage in WindowsXP taskmanager is still growing. Is the cache
option not working, or am I missing something?
Please find attached my sample code showing this issue. Maybe I need
to file a Jire. Could someone please review it and tell me if I need
to add it or jira or how to fix?
<canvas height="100%" width="100%" debug="false">
<simplelayout axis="y" spacing="10" inset="10"/>
<attribute name="cnt" type="number" value="0"/>
<view name="imagecontainer" x="${parent.width/2 - this.width/2}"
width="512" height="512" bgcolor="#000000">
<view name="image" id="imageviewport" stretches="both"
x="${parent.width / 2 - this.width / 2}"
y="${parent.height / 2 - this.height / 2}">
</view>
</view>
<view name="imagecontrolview" x="${parent.width/2 - this.width/2}">
<simplelayout axis="x" spacing="10"/>
<button text="Start">
<handler name="onclick">
<![CDATA[
this.onclick.clearDelegates();
this.del = new LzDelegate(this,
"stopTimer");
this.del.register(this, "onclick");
parent.time.updateTimer(this);
]]>
</handler>
<method name="stopTimer">
<![CDATA[
this.setAttribute("text", "Start");
parent.time.del.disable();
this.onclick.clearDelegates();
this.del = new LzDelegate(this,
"restartTimer");
this.del.register(this, "onclick");
]]>
</method>
<method name="restartTimer">
<![CDATA[
this.setAttribute("text", "Stop");
parent.time.del.enable();
parent.time.updateTimer(this);
this.onclick.clearDelegates();
this.del = new LzDelegate(this,
"stopTimer");
this.del.register(this, "onclick");
]]>
</method>
</button>
<text name="time" resize="true"
fontsize="14" fontstyle="bold">
<method name="updateTimer">
<![CDATA[
canvas.loadImage();
if (typeof this.del == "undefined")
{
this.del = new
LzDelegate(this, "updateTimer");
LzTimer.addTimer(this.del,
100);
}
else
LzTimer.resetTimer(this.del,
100);
]]>
</method>
</text>
</view>
<method name="loadImage">
<![CDATA[
canvas.cnt++;
canvas.imagecontrolview.time.setAttribute("text",
cnt);
var d = new Date();
var t = d.getDate() + "-" + (d.getMonth()+1) + "-" +
d.getFullYear() + "_" + d.getHours()
+ ":" + d.getMinutes() + ":" +
d.getSeconds() + "." + d.getMilliseconds();
Debug.write("LoadImage: " + cnt);
canvas.imagecontainer.image.setSource("http://www.kroll-mobile.de/rw_common/
images/140x140shadow.png?ts=" + t);
delete d;
delete t;
]]>
</method>
</canvas>
KInd regards,
Michael.
