Corda Server™ supports auto-updating FLASH images so that Corda® image refresh themselves, or load another Corda image, at regular intervals. This allows you to, for example, automatically provide a new graph with updated data every 15 seconds, without any client-side scripting.
Warning: The auto-updating images feature is not compatible with animations.
Auto-updating is supported in FLASH images only. To use auto-updating, provide an Image Template file with a list of one or more URLs from which it can obtain new FLASH images, and a time interval (in seconds) between each refresh.
When a Web browser loads the initial FLASH image, the image instructs the FLASH plug-in to cycle through the URLs specified in the Image Template file. These URLs can point to any FLASH image—even those not generated by Corda Server.
The plug-in cycles through these images continously, using the auto-update interval specified in the Image Template file. This means, for example, if you only specify one FLASH image URL, the plug-in continously refreshes the image from the URL at the specified interval.
Note: Do not use auto-update settings in any of the secondary FLASH images you are loading—just the initial FLASH image that is being loaded into the Web page.
This section includes the following topics:
Note: Some Web browsers may experience caching problems with auto-updating FLASH images. To avoid this, set the Content Expiration header for each FLASH image you load to expire immediately. For more information, see Solving Caching Issues with Auto-Updated FLASH Images.
The easiest way to configure auto-updating settings is in Corda Builder™. For more information, see Auto-Updating Flash* Images in the Corda Builder User Guide.
ITXML lets you specify auto-update settings dynamically. To do so, modify the AutoUpdateURLs attribute of the Chart tag.
For example, to retrieve a FLASH image from http://www.myserver.com/images.bar.swf, set the URL as follows:
myImage.addITXML("<cit:image-template-auto-update url-list="http://texas/images/bar/swf"/>");
Change the frequency at which this FLASH image updates by setting AutoUpdateInterval:
myImage.addITXML("<cit:image-template-auto-update update-list=”http://localhost:8080/corda7/image1.swf
http://localhost:8080/corda7/image2.swf”/>;
To cycle through multiple URLs, delimit each URL in the AutoUpdateURLs string with 
:
myImage.addITXML("<cit:image-template-auto-update
update-list=
"http://<server_address>:2001/?@_FILEimage_templates\examples\bar.itxml@_DONTCACHE

http://<server_address>:2001/?@_FILEimage_templates\examples\pie.itxml@_DONTCACHE

http://<server_address>:2001/?@_FILEimage_templates\examples\line.itxml@_DONTCACHE/>");
Since the specified URLs must return FLASH images instead of Web pages, Corda Embedder's getBytes method makes it possible for you to send a FLASH Corda image to a Web client directly through a Web application. For more information, see Returning Images Directly from Web Applications.
When auto-updating FLASH images frequently, consider using Corda Server's scheduling capabilities to help prevent overloading the Web server with image generation for every Web client that is viewing the auto-updating FLASH image.
The scheduler sets up Corda Server to generate a new version of a graph or map at regular intervals, which are then saved to a Web application server or another Corda Server for retrieval by any Web client. For more information, see Scheduling Corda Image Generation
Important: Some Web browsers may experience caching problems with auto-updating FLASH images. To avoid this, set the Content Expiration header for each FLASH image you load to expire immediately. For more information, see Solving Caching Issues with Auto-Updated FLASH Images below.
Dynamically updating FLASH images, but not seeing the changes reflected in the Corda image, might indicate Web browser caching problems.
When a Web server sends a file (whether it be an image or a Web page) to a Web browser, it includes instructions in a header to help the Web browser know how to deal with that file. One piece of information it sends is content-expiration—that is, how long the Web browser should wait before checking the server to see if the file has been updated. Receiving another copy of the image or Web page again, prior to the content expiration, causes the Web browser to display the original image instead of the updated image.
Some Web browsers make assumptions about content-expiration that can cause the Web browser not to check for updated content in auto-update FLASH images. There are several ways to fix this problem:
One (albeit less desirable) solution to this problem is to change the Web browser settings to always check for newer versions of Web pages and images.
To do this in Internet Explorer, for example, select Tools > Internet Options. Under Temporary Internet Files, click the Settings button. Under the Check for Newer Versions of Stored Pages option, select Every Visit to the Page.
The main drawback of this solution is that every client must make these changes.
To avoid having to rely on clients to change Web browser settings, modify the content-expiration header for each FLASH image in an auto-update scenario so that it expires immediately. Setting the FLASH images to expire immediately force the Web browser to always check for updated images.
When retrieving FLASH images from Corda Server using server commands, use the @_DONTCACHE command to force the content to expire immediately. For example:
http://<server_address>:2001/?@_FILEimage_templates\examples\bar.itxml@_DONTCACHE
When loading a previously saved image (see Scheduling with Server Commands), use a command similar to the following:
http://<server_address>:2001/?@_LOADimages/test.swf@_FLASH@_DONTCACHE
Loading FLASH images that have been saved to a Web server require you to set the content-expiration for the image on a file-by-file basis. The exact procedure for doing this varies by Web server, and some servers may not provide a mechanism for setting content expiration.
For example, Windows* IIS uses the following procedure:
Open the Internet Information Services management console
Using the tree on the left, browse to the FLASH image file for which you want to change content-expiration settings.
Right-click the FLASH image file and select Properties
Select the HTTP-Headers tab
Check the Enable Content Expiration box
Under Content Should, select Expire Immediately
Using a Web application to output FLASH image directly to the Web browser (using the getBytes command), set the content-expiration header programmatically. For example, in Java*:
response.setHeader("Cache-Control","no-cache");
response.setHeader("Pragma","no-cache");
response.setDateHeader ("Expires", 0);
In ASP.NET:
Response.Cache.SetExpires(DateTime.Now);
See the Web application server's documentation for information about setting content expiration programmatically.