Using CORBA Request-Level Interceptors

InterceptorData Sample Interceptors

This chapter describes the following two sample interceptors that are designed to be used with the PersonQuery sample application:

InterceptorDataClient Interceptor, which is installed on the machine hosting the PersonQuery client component.
InterceptorDataTarget Interceptor, which is installed on the machine hosting the PersonQuery server component.

This chapter explains how each interceptor works, then shows how to build and run them with the PersonQuery sample application.

InterceptorDataClient Interceptor

The InterceptorDataClient interceptor intercepts and logs each client application request and reply parameters. This interceptor also allows certain operations on the PersonQuery server application to be invoked by users of the client application who meet specific criteria. The InterceptorDataClient interceptor implements the InterceptorDataClient interface, which inherits from the ClientRequestInterceptor class.

The InterceptorDataClient class implements the methods as follows:

id()

This method returns the string InterceptorDataClient.

shutdown()

This method removes the request from the tracker object.

exception_occurred()

When invoked by the ORB, this method removes the request from the tracker object.

client_invoke()

This method determines if the interface and operation are "of interest." If the client request is "of interest," this method parses the request parameters and outputs the parameters to the log file. If the client request is not "of interest," this method simply returns.

client_response()

This method determines if the interface and operation in the request are "of interest." If the interface and operation are "of interest," this method walks through the CORBA DataInputStream parameter to obtain the reply parameters and write them to the log file. If the interface and operation in the request are not "of interest," this method simply returns.

In addition, the data interceptor provides the InterceptorDataClientInit method to initialize the client interceptor class.

InterceptorDataTarget Interceptor

The InterceptorDataTarget interceptor intercepts and logs request and reply data parameters. This interceptor also removes sensitive data from specific reply parameters by masking the data with x characters. The InterceptorDataTarget interceptor implements the InterceptorDataTarget interface, which inherits from the TargetRequestInterceptor class.

The InterceptorDataTarget class implements the methods as follows:

id()

This method returns the string InterceptorDataTarget.

shutdown()

This method simply returns.

exception_occurred()

This method removes the request from the tracker object.

target_invoke()

This method determines if the interface and operation are "of interest." If so, this method parses the request parameters and outputs that data to the log file. If the interface and operation in the request are not "of interest," this method simply returns. If the operation in the request is exit, this method returns the status value INVOKE_NO_EXCEPTION.

target_response()

This method determines if the interface and operation are "of interest." If so, this method walks through the DataInputStream parameter to obtain the response parameters and output to the log file. Sensitive data items are substituted in the log. For example, a person's social security number will not be output to the log. If the interface and operation in the request are not "of interest," this method simply returns.

In addition, the data interceptor provides the InterceptorDataTargetInit method to initialize the target interceptor class.

Implementing the InterceptorData Interceptors

Information about the code used to implement the InterceptorData interceptors is provided in Developing CORBA Request-Level Interceptors. Refer to that chapter for information about how to do the following:

Starting the Implementation File on page 2-3.

Initializing the Interceptor at Run Time on page 2-4.

Obtaining the Interface Name from a Request on page 2-5.

Identifying Operations in the Request on page 2-5.

Implementing the Interceptor's Response Operation on page 2-6.

Reading Parameters Out of a Data Input Stream on page 2-7.

Registering and Running the InterceptorData Interceptors

When you run the makefile that builds the PersonQuery sample application in PersonQuery Sample Application, the entire set of sample interceptors are built as well, including the InterceptorData interceptors. This section describes how to register the InterceptorData interceptor so that it works with PersonQuery application at run time.

To register and run the InterceptorData client and server interceptors:

Change directory to the InterceptorData sample directory, where workdirectory represents the name of the directory into which you copied the interceptor sample applications in Chapter , "PersonQuery Sample Application:"

Windows 2003

> cd <workdirectory>\cxx\data_cxx
UNIX

$ cd <workdirectory>/cxx/data_cxx

Windows 2003

> nmake -f makefile.nt config
UNIX

$ make -f makefile.mk config

Boot the CORBA server and run the CORBA client:

Windows 2003

> cd <workdirectory>\cxx\app_cxx > tmboot -y > PersonQueryClient
UNIX

> cd <workdirectory>/cxx/app_cxx > tmboot -y > PersonQueryClient

Perform any number of invocations using the PersonQuery client application, using the command syntax described in PersonQuery Sample Application.

Stop the PersonQuery application:

> tmshutdown -y

Examining the Interceptor Output

The InterceptorData client and target interceptors log each invocation. For each PersonQuery application session, the client interceptor creates a log file named InterceptorDataClientxxx.out, and the target interceptor creates a log file named InterceptorDataTargetxxx.out. This section shows sample log file data for each interceptor.

Sample Client Interceptor Log Output

InterceptorDataClientInit called
ClientInterceptorData::id called

ClientInterceptorData::client_invoke called
ClientInterceptorData::client_response called
   Request Id:     1
   unable to find request for this reply (must not be one we care about)

ClientInterceptorData::client_invoke called
   Request Id:     2
   Interface:      IDL:beasys.com/PersonQuery:1.0
   Operation:      findPerson
   Parameters:
                            name:           ALISTER LANCASHIRE
                            address:        3 PENNY LANE
                                            LONDON GB UK
                            ss:             999-99-9999
                            sex:            can't tell
                            age(yrs.):      85
                            marital status: single
                            hobby:          stamp collecting
                            date-of-birth:  11/25/1913
                            height(in.):    32
                            weight(lbs.):   57
                            hair color:     unknown
                            eye color:      blue
                            skin color:     white
                            other markings: missing limb

Sample Target Interceptor Log Output

InterceptorDataTargetInit called
TargetInterceptorData::id called

TargetInterceptorData::target_response called
   Request Id:     2
   ReplyStatus:    GIOP::NO_EXCEPTION
   Interface:      IDL:beasys.com/PersonQuery:1.0
   Operation:      findPerson
   Method Result:  TRUE
   Parameters:
                   Maximum: 8
                   Length:  8

                   Item 0
                            name:           ALISTER LANCASHIRE
                            address:        3 PENNY LANE
                                            LONDON GB UK
                            ss:             NO PRIVILEDGE
                            sex:            NO PRIVILEDGE
                            age (years):    NO PRIVILEDGE
                            marital status: NO PRIVILEDGE
                            hobby:          stamp collecting
                            date-of-birth:  NO PRIVILEDGE
                            height (in.):   32
                            weight (lbs.):  57
                            hair color:     unknown
                            eye color:      blue

                            skin color:     NO PRIVILEDGE
                            other markings: missing limb

Unregistering the Interceptors

After you have run the PersonQuery sample application with the InterceptorData sample interceptors, you can unregister those interceptors using the following steps:

Shut down all running CORBA applications by entering the following command:

> tmshutdown -y

Windows 2003

> cd <workdirectory>\cxx\data_cxx
UNIX

$ cd <workdirectory>/cxx/data_cxx

Unregister the interceptors:

Windows 2003

> nmake -f makefile.nt unconfig
UNIX

$ make -f makefile.mk unconfig