ICM Server Clipboard (SAP Library - Architecture of the SAP Web Application Server)

ICM Server Clipboard

Definition

The ICM server clipboard is a service that is used to temporarily store data BLOBs (binary large objects). If these are then requested in an HTTP request, they can be provided very quickly.

Use

In addition to the ICM Server Cache there is also the server clipboard in the ICM. The data BLOBs that are stored in the ICM server clipboard are assigned a key that enables them to be retrieved later in sequence requests. The same technology is used as that in the ICM server cache, thus ensuring high performing access.

If you want to store objects in the ICM server clipboard within the framework of your Internet application, you can use the method SERVER_CACHE_UPLOAD of class CL_HTTP_SERVER to do this. This is described below.

Caution

The ICM clipboard should be used to store objects temporarily! You cannot assume that the objects will still be available at a much later date!

Structure

The HTTP Request Handler, that wants to use this functionality creates a temporary response object for each BLOB (GIF images, for example) that is embedded in the output page. With the help of the class constructor, an empty response object is created, which is then filled with contents using standard methods such as APPEND_DATA() (see also IF_HTTP_ENTITY). In this way, additional attributes such as the cache retention period, compression and so on can be set using known methods (SERVER_CACHE_EXPIRES, SET_COMPRESSION and so on).

Objects that were generated using SERVER_CACHE_UPLOAD can be uploaded to the server clipboard using a uniquely assigned URL. At the same time, the links in the current output page to the URLs that are assigned each time the SERVER_CACHE_UPLOAD is called are serialized in the HTML data stream. Method SERVER_CACHE_UPLOAD has the following import parameters:

URL: The URL under which the BLOB is stored in the ICM server cache.

Response: Reference to the response object

Scope: Specifies whether the data that should be stored locally in the cache of the current ICM belongs to the current SAP Web AS, or if it should be stored globally in the caches of all ICMs that belong to the system. The default is local.

The requests on the embedded objects in this page are therefore handled in the sequence in which they are generated by the HTTP client (browser) from the ICM server clipboard.

See also:

IF_HTTP_RESPONSE and IF_HTTP_REQUEST

Internet Communication Framework

Integration

The ICM server cache is used. If an object is stored in the ICM server clipboard, it is located in a special part of the ICM server cache. In contrast to normal cache entries, you must ensure that the object is located in the clipboard. In the case of a cache miss, it cannot be fetched from the server.

Example

An application contains a personalized list that contains a lot of memory-intensive graphics. They should be displayed after you have logged on, but it should not take a long time to generate them. The application must be programmed in such a way that the data is stored in the ICM clipboard server before the page should be generated.

A sample application is embedding XML/XSL documents. This function is not directly supported by all browsers.