Smile CDR v2023.02.PRE
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12.5FHIR Client interceptor Examples

 

This page contains example interceptors that can be registered with the FHIR Client.

12.5.1Example: Starter Client interceptor for all CLIENT_xxx pointcuts

 

The following example shows an interceptor that can be used as a starter Client interceptor, implementing a hook method for each available pointcut.

/**
 * This interceptor is intended to be used with a FHIR client (IRestfulClient, or its implementations)
 * and must be registered with it, before being called.
 * <p>
 * Example:
 * 		IGenericClient fhirClient = FhirContext.forR4().newRestfulGenericClient("http://localhost:8000/");
 * 		fhirClient.registerInterceptor(new ClientInterceptorTemplate());
 * Afterward, calls done using 'fhirClient' will be intercepted by 'ClientInterceptorTemplate'
 * and CLIENT_REQUEST and CLIENT_RESPONSE hook methods will be called.
 * </p><p>
 * Client interceptor can be useful to change the behaviour of a FHIR client before it send requests to a FHIR Endpoint,
 * by changing the url/headers/content for example,
 * or by doing some checks (on http status, headers, etc.) on the response received from a FHIR Endpoint.
 * Currently, the response received cannot be modified by the CLIENT_RESPONSE hook.
 * </p><p>
 * In fact, this is how the FHIR client BasicAuthInterceptor, BearerTokenAuthInterceptor, LoggingInterceptor,
 * and others are actually implemented.
 * </p>
 * Can be used as a starting point for your client interceptor.
 */
@SuppressWarnings({"unused", "EmptyTryBlock"})
@Interceptor
public class ClientInterceptorTemplate {

	private static final Logger ourLog = LoggerFactory.getLogger(ClientInterceptorTemplate.class);

	@Hook(Pointcut.CLIENT_REQUEST)
	public void clientRequest(
		IHttpRequest theHttpRequest,
		IRestfulClient theRestfulClient) {

		ourLog.info("Interceptor CLIENT_REQUEST - started");
		StopWatch stopWatch = new StopWatch();
		try {
			// your implementation goes here
		} finally {
			ourLog.info("Interceptor CLIENT_REQUEST - ended, execution took {}", stopWatch);
		}
	}

	@Hook(Pointcut.CLIENT_RESPONSE)
	public void clientResponse(
		IHttpRequest theHttpRequest,
		IHttpResponse theHttpResponse,
		IRestfulClient theRestfulClient) {

		ourLog.info("Interceptor CLIENT_RESPONSE - started");
		StopWatch stopWatch = new StopWatch();
		try {
			// your implementation goes here
		} finally {
			ourLog.info("Interceptor CLIENT_RESPONSE - ended, execution took {}", stopWatch);
		}
	}
}