SOAP Callback Operations for Web Services Call-In

When clients call in to Uniface web services they may provide a SOAP envelope that includes encrypted content, or information that Uniface itself does not handle or require, and they may expect a similar response back. To ensure that you can handle and construct SOAP envelopes that meet these requirements, you can implement callback operations that are automatically called before and after the target operation of the web service.

• SOAP_CALLIN_PRE—called before the target operation is executed. It can be used to examine the SOAP envelope and header, decrypt encrypted content, and modify the SOAP header that is passed to the target web service.
• SOAP_CALLIN_POST—called after the target operation has executed. It can be used to encrypt content and modify the response SOAP envelope.

These operations can be implemented in the web service itself or in a separate service that provides processing for all your Uniface web services.

The list of services that implement the operations must be specified in the $SOAP_CALLIN_CB setting in the assignment file of the Uniface Web Application Server (by default, wasv.asn).

When a client calls in to a Uniface web service, Uniface calls the SOAP_CALLIN_PRE operation on the services specified by the $SOAP_CALLIN_CB assignment setting, in the order given. Prior to sending the response, the SOAP_CALLIN_POST operation is called, this time processing the list of services in reverse order. This makes it possible to deploy extra processing on the envelope without having to change existing pre and post operations.

Note:  The SOAP callback operations supercede the Uniface Web Services Call-In API, which provides similar functionality as 3GL functions. If you have existing web services that make use of the API, these will continue to work, but the API is obsolete and no longer maintained. For new web services, you should use the callback operations rather than the API.

Related Topics