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Merged
MartinWheelerMT merged 1 commit into from
Sep 8, 2026
Merged

Refactor SdsFilter for readabilty #353

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165 changes: 74 additions & 91 deletions service/src/main/java/uk/nhs/adaptors/gpc/consumer/filters/SdsFilter.java
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Original file line number Diff line number Diff line change
@@ -1,29 +1,8 @@
package uk.nhs.adaptors.gpc.consumer.filters;

import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import static uk.nhs.adaptors.gpc.consumer.gpc.InteractionIds.DOCUMENT_MIGRATE_ID;
import static uk.nhs.adaptors.gpc.consumer.gpc.InteractionIds.DOCUMENT_READ_ID;
import static uk.nhs.adaptors.gpc.consumer.gpc.InteractionIds.DOCUMENT_SEARCH_ID;
import static uk.nhs.adaptors.gpc.consumer.gpc.InteractionIds.MIGRATE_STRUCTURED_ID;
import static uk.nhs.adaptors.gpc.consumer.gpc.InteractionIds.PATIENT_SEARCH_ID;
import static uk.nhs.adaptors.gpc.consumer.gpc.InteractionIds.STRUCTURED_ID;
import static uk.nhs.adaptors.gpc.consumer.utils.HeaderConstants.SSP_TRACE_ID;
import static uk.nhs.adaptors.gpc.consumer.utils.OperationOutcomes.buildErrorResponse;

import java.net.URI;
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.function.BiFunction;
import java.util.stream.Collectors;

import jakarta.annotation.PostConstruct;

import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.jetbrains.annotations.NotNull;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
Expand All @@ -32,6 +11,10 @@
import org.springframework.cloud.gateway.support.ServerWebExchangeUtils;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.http.server.PathContainer;
import org.springframework.http.server.RequestPath;
import org.springframework.http.server.reactive.ServerHttpRequest;
Expand All @@ -42,33 +25,46 @@
import org.springframework.web.reactive.function.client.WebClientResponseException;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.util.UriComponentsBuilder;

import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import reactor.core.publisher.Mono;
import uk.nhs.adaptors.gpc.consumer.filters.exception.SdsFilterException;
import uk.nhs.adaptors.gpc.consumer.sds.SdsClient;
import uk.nhs.adaptors.gpc.consumer.sds.exception.SdsException;
import uk.nhs.adaptors.gpc.consumer.utils.LoggingUtil;
import uk.nhs.adaptors.gpc.consumer.utils.OperationOutcomes;
import uk.nhs.adaptors.gpc.consumer.utils.QueryParamsEncoder;

import java.net.URI;
import java.nio.charset.StandardCharsets;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.function.BiFunction;

import static uk.nhs.adaptors.gpc.consumer.gpc.InteractionIds.DOCUMENT_MIGRATE_ID;
import static uk.nhs.adaptors.gpc.consumer.gpc.InteractionIds.DOCUMENT_READ_ID;
import static uk.nhs.adaptors.gpc.consumer.gpc.InteractionIds.DOCUMENT_SEARCH_ID;
import static uk.nhs.adaptors.gpc.consumer.gpc.InteractionIds.MIGRATE_STRUCTURED_ID;
import static uk.nhs.adaptors.gpc.consumer.gpc.InteractionIds.PATIENT_SEARCH_ID;
import static uk.nhs.adaptors.gpc.consumer.gpc.InteractionIds.STRUCTURED_ID;
import static uk.nhs.adaptors.gpc.consumer.utils.HeaderConstants.SSP_FROM;
import static uk.nhs.adaptors.gpc.consumer.utils.HeaderConstants.SSP_INTERACTION_ID;
import static uk.nhs.adaptors.gpc.consumer.utils.HeaderConstants.SSP_TO;
import static uk.nhs.adaptors.gpc.consumer.utils.HeaderConstants.SSP_TRACE_ID;

@Component
@Slf4j
@RequiredArgsConstructor(onConstructor = @__(@Autowired))
public class SdsFilter implements GlobalFilter, Ordered {

public static final int SDS_FILTER_ORDER = RouteToRequestUrlFilter.ROUTE_TO_URL_FILTER_ORDER + 1;
public static final String SSP_INTERACTION_ID = "Ssp-InteractionID";
private static final String DOCUMENT_REFERENCE_SUFFIX = "/DocumentReference";
public static final String OPERATION_OUTCOME = "operationOutcome";
public static final String INTERNAL_SERVER_ERROR = "INTERNAL_SERVER_ERROR";
public static final String EXCEPTION = "exception";
public static final String STRUCTURE = "structure";
public static final String NOT_FOUND = "not-found";
public static final String BAD_GATEWAY = "BAD_GATEWAY";
public static final String BAD_REQUEST = "BAD_REQUEST";
public static final String PATIENT_NOT_FOUND = "PATIENT_NOT_FOUND";
public static final String NO_ENDPOINT_AVAILABLE = "NO_ENDPOINT_AVAILABLE";
public static final String MISSING_HEADER_EXCEPTION_MESSAGE = "Missing or empty %s Header Value for SDS Request";

private final SdsClient sdsClient;
Expand All @@ -77,12 +73,12 @@ public class SdsFilter implements GlobalFilter, Ordered {
@Override
public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
return getGpcProviderEndpointDetails(exchange)
.flatMap(gpcProviderEndpointDetails -> appendSspHeadersToExchangeIfRequired(
exchange,
chain,
gpcProviderEndpointDetails)
)
.onErrorResume(Exception.class, e -> errorResponse(exchange, e));
.flatMap(gpcProviderEndpointDetails -> appendSspHeadersToExchangeIfRequired(
exchange,
chain,
gpcProviderEndpointDetails)
)
.onErrorResume(Exception.class, e -> buildErrorResponse(exchange, e));
}

private Mono<SdsClient.SdsResponseData> getGpcProviderEndpointDetails(ServerWebExchange exchange) {
Expand Down Expand Up @@ -138,10 +134,10 @@ private Mono<Void> appendSspHeadersToExchangeIfRequired(
? chain.filter(exchange)
: getGpcConsumerAsid(exchange)
.flatMap(gpcConsumerAsid -> addMissingSspHeaders(
gpcConsumerAsid,
exchange,
chain,
gpcProviderEndpointDetails
gpcConsumerAsid,
exchange,
chain,
gpcProviderEndpointDetails
));
}

Expand All @@ -151,21 +147,17 @@ private Mono<? extends Void> addMissingSspHeaders(
GatewayFilterChain chain,
SdsClient.SdsResponseData gpcProviderEndpointDetails
) {
var mutatedExchange = appendSspHeaderWhenAbsent(
exchange,
gpcProviderEndpointDetails.getNhsSpineAsid(),
"Ssp-To"
);
mutatedExchange = appendSspHeaderWhenAbsent(mutatedExchange, gpcConsumerAsid, "Ssp-From");
var mutatedExchange = appendSspHeaderWhenAbsent(exchange, gpcProviderEndpointDetails.getNhsSpineAsid(), SSP_TO);
mutatedExchange = appendSspHeaderWhenAbsent(mutatedExchange, gpcConsumerAsid, SSP_FROM);
return chain.filter(mutatedExchange);
}

private static @NotNull Mono<Void> errorResponse(ServerWebExchange exchange, Exception e) {
private static @NotNull Mono<Void> buildErrorResponse(ServerWebExchange exchange, Exception e) {
HttpStatus status = mapExceptionToHttpStatus(e);
String spineCode = mapWebClientExceptionToSpineCode(e);
String fhirCode = mapSpineCodeToFhirCode(spineCode);

ResponseEntity<String> errorResponse = buildErrorResponse(status, spineCode, fhirCode, e.getMessage());
ResponseEntity<String> errorResponse = OperationOutcomes.buildErrorResponse(status, spineCode, fhirCode, e.getMessage());
ServerHttpResponse response = exchange.getResponse();
response.setStatusCode(errorResponse.getStatusCode());
response.getHeaders().setContentType(MediaType.APPLICATION_JSON);
Expand All @@ -176,13 +168,12 @@ private Mono<? extends Void> addMissingSspHeaders(
}

private static HttpStatus mapExceptionToHttpStatus(Exception e) {
if (e instanceof WebClientRequestException) {
return HttpStatus.BAD_GATEWAY;
}
if (e instanceof WebClientResponseException webClientResponseEx) {
return HttpStatus.resolve(webClientResponseEx.getStatusCode().value());
}
return HttpStatus.INTERNAL_SERVER_ERROR;
return switch (e) {
case WebClientRequestException ignored -> HttpStatus.BAD_GATEWAY;
case WebClientResponseException webClientResponseEx ->
HttpStatus.resolve(webClientResponseEx.getStatusCode().value());
default -> HttpStatus.INTERNAL_SERVER_ERROR;
};
}

private static String mapWebClientExceptionToSpineCode(Exception e) {
Expand Down Expand Up @@ -216,32 +207,20 @@ private Mono<String> getGpcConsumerAsid(ServerWebExchange exchange) {
}

private String extractOdsCode(RequestPath requestPath) {
Optional<PathContainer.Element> odsCodeElement = requestPath.elements()
.stream()
return requestPath.elements().stream()
.skip(1)
.findFirst();

if (odsCodeElement.isPresent()) {
return odsCodeElement.get().value();
}

throw new IllegalArgumentException("URL does not contain ODS code in its second element");
.findFirst()
.map(PathContainer.Element::value)
.orElseThrow(() -> new IllegalArgumentException("URL does not contain ODS code in its second element"));
}

@NotNull
private ServerWebExchange appendSspHeaderWhenAbsent(ServerWebExchange exchange, String asid, String sspHeader) {
String ssp = Optional.ofNullable(exchange.getRequest().getHeaders().getFirst(sspHeader))
.filter(StringUtils::hasText)
.orElse(asid);

List<String> incomingSspHeaderValue = exchange.getRequest().getHeaders().get(sspHeader);
String ssp = asid;

if (incomingSspHeaderValue != null) {
ssp = incomingSspHeaderValue.stream().findFirst().orElse(asid);
}

ServerHttpRequest mutateRequest = exchange.getRequest()
.mutate()
.header(sspHeader, ssp)
.build();
ServerHttpRequest mutateRequest = exchange.getRequest().mutate().header(sspHeader, ssp).build();

return exchange.mutate().request(mutateRequest).build();
}
Expand All @@ -256,44 +235,48 @@ public int getOrder() {
@SuppressWarnings("unused")
public void initializeSdsRequestFunctions() {
sdsRequestFunctions = Map.of(
STRUCTURED_ID, sdsClient::callForGetStructuredRecord,
PATIENT_SEARCH_ID, sdsClient::callForPatientSearchAccessDocument,
DOCUMENT_SEARCH_ID, sdsClient::callForSearchForDocumentRecord,
DOCUMENT_READ_ID, sdsClient::callForRetrieveDocumentRecord,
DOCUMENT_MIGRATE_ID, sdsClient::callForMigrateDocumentRecord,
MIGRATE_STRUCTURED_ID, sdsClient::callForMigrateStructuredRecord
STRUCTURED_ID, sdsClient::callForGetStructuredRecord,
PATIENT_SEARCH_ID, sdsClient::callForPatientSearchAccessDocument,
DOCUMENT_SEARCH_ID, sdsClient::callForSearchForDocumentRecord,
DOCUMENT_READ_ID, sdsClient::callForRetrieveDocumentRecord,
DOCUMENT_MIGRATE_ID, sdsClient::callForMigrateDocumentRecord,
MIGRATE_STRUCTURED_ID, sdsClient::callForMigrateStructuredRecord
);
}

private Mono<SdsClient.SdsResponseData> performRequestAccordingToInteractionId(String interactionId,
String organisation, String sspTraceId, ServerWebExchange exchange) {
private Mono<SdsClient.SdsResponseData> performRequestAccordingToInteractionId(
String interactionId,
String organisation,
String sspTraceId,
ServerWebExchange exchange
) {
if (sdsRequestFunctions.containsKey(interactionId)) {
LoggingUtil.info(LOGGER, exchange, "Performing request with organisation \"{}\" and NHS service endpoint id \"{}\"",
organisation, interactionId);
organisation, interactionId);
return sdsRequestFunctions.get(interactionId)
.apply(organisation, sspTraceId);
.apply(organisation, sspTraceId);
}
throw new IllegalArgumentException(String.format("Not recognised InteractionId %s", interactionId));
}

private Optional<URI> prepareLookupUri(String serviceRootUrl, ServerHttpRequest originalRequest) {
var originalRequestPath = originalRequest.getPath();
var originalRequestPathValues = originalRequestPath.elements().stream()
.map(PathContainer.Element::value)
.collect(Collectors.toList());
.map(PathContainer.Element::value)
.toList();
int indexOfPatientInFhirPath = originalRequestPathValues.lastIndexOf("Patient");
int indexOfBinaryInFhirPath = originalRequestPathValues.lastIndexOf("Binary");
int indexOfStartOfFhirPath = Math.max(indexOfPatientInFhirPath, indexOfBinaryInFhirPath);
if (indexOfStartOfFhirPath < 0) {
throw new SdsFilterException("Unable to detect a supported FHIR path in the original request");
}
String fhirRequestPathPart = originalRequest.getPath().subPath(indexOfStartOfFhirPath - 1)
.toString();
.toString();
String uriWithoutQueryParameters = serviceRootUrl + fhirRequestPathPart;
URI constructedUri = UriComponentsBuilder.fromUriString(uriWithoutQueryParameters)
.queryParams(originalRequest.getQueryParams())
.build()
.toUri();
.queryParams(originalRequest.getQueryParams())
.build()
.toUri();
return Optional.of(constructedUri);
}
}
}
3 changes: 3 additions & 0 deletions service/src/main/java/uk/nhs/adaptors/gpc/consumer/utils/HeaderConstants.java
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Expand Up @@ -2,6 +2,9 @@

public final class HeaderConstants {
public static final String SSP_TRACE_ID = "Ssp-TraceID";
public static final String SSP_INTERACTION_ID = "Ssp-InteractionID";
public static final String SSP_FROM = "Ssp-From";
public static final String SSP_TO = "Ssp-To";

private HeaderConstants() { }
}
3 changes: 2 additions & 1 deletion service/src/test/java/uk/nhs/adaptors/gpc/consumer/gpc/SdsFilterTest.java
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Expand Up @@ -32,9 +32,10 @@
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.Mockito.when;
import reactor.test.StepVerifier;
import static uk.nhs.adaptors.gpc.consumer.filters.SdsFilter.SSP_INTERACTION_ID;

import static uk.nhs.adaptors.gpc.consumer.gpc.InteractionIds.DOCUMENT_READ_ID;
import static uk.nhs.adaptors.gpc.consumer.gpc.InteractionIds.STRUCTURED_ID;
import static uk.nhs.adaptors.gpc.consumer.utils.HeaderConstants.SSP_INTERACTION_ID;
import static uk.nhs.adaptors.gpc.consumer.utils.HeaderConstants.SSP_TRACE_ID;
import static org.assertj.core.api.Assertions.assertThat;

Expand Down
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