Java tutorial
/* * * Copyright (c) 2016 Amazon.com, Inc. or its affiliates. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"). * You may not use this file except in compliance with the License. * A copy of the License is located at * * http://ksyun.com/apache2.0 * * or in the "license" file accompanying this file. This file is distributed * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either * express or implied. See the License for the specific language governing * permissions and limitations under the License. * */ package com.ksc.http; import java.io.IOException; import java.util.Map; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import com.fasterxml.jackson.core.JsonFactory; import com.fasterxml.jackson.core.JsonParser; import com.ksc.KscWebServiceResponse; import com.ksc.ResponseMetadata; import com.ksc.annotation.SdkInternalApi; import com.ksc.internal.CRC32MismatchException; import com.ksc.transform.JsonUnmarshallerContext; import com.ksc.transform.JsonUnmarshallerContextImpl; import com.ksc.transform.Unmarshaller; import com.ksc.transform.VoidJsonUnmarshaller; import com.ksc.util.CRC32ChecksumCalculatingInputStream; import com.ksc.util.ValidationUtils; /** * Default implementation of HttpResponseHandler that handles a successful response from an AWS * service and unmarshalls the result using a JSON unmarshaller. * * @param <T> Indicates the type being unmarshalled by this response handler. */ @SdkInternalApi public class JsonResponseHandler<T> implements HttpResponseHandler<KscWebServiceResponse<T>> { /** * The JSON unmarshaller to use when handling the response */ private Unmarshaller<T, JsonUnmarshallerContext> responseUnmarshaller; /** * Shared logger for profiling information */ private static final Log log = LogFactory.getLog("com.ksc.request"); private final JsonFactory jsonFactory; private final boolean needsConnectionLeftOpen; private final boolean isPayloadJson; private final Map<Class<?>, Unmarshaller<?, JsonUnmarshallerContext>> simpleTypeUnmarshallers; /** * Constructs a new response handler that will use the specified JSON unmarshaller to unmarshall * the service response and uses the specified response element path to find the root of the * business data in the service's response. * * @param responseUnmarshaller The JSON unmarshaller to use on the response. * @param simpleTypeUnmarshallers List of unmarshallers to be used for scalar types. * @param jsonFactory the json factory to be used for parsing the response. */ public JsonResponseHandler(Unmarshaller<T, JsonUnmarshallerContext> responseUnmarshaller, Map<Class<?>, Unmarshaller<?, JsonUnmarshallerContext>> simpleTypeUnmarshallers, JsonFactory jsonFactory, boolean needsConnectionLeftOpen, boolean isPayloadJson) { /* * Even if the invoked operation just returns null, we still need an * unmarshaller to run so we can pull out response metadata. * * We might want to pass this in through the client class so that we * don't have to do this check here. */ this.responseUnmarshaller = responseUnmarshaller != null ? responseUnmarshaller : new VoidJsonUnmarshaller<T>(); this.needsConnectionLeftOpen = needsConnectionLeftOpen; this.isPayloadJson = isPayloadJson; this.simpleTypeUnmarshallers = ValidationUtils.assertNotNull(simpleTypeUnmarshallers, "simple type unmarshallers"); this.jsonFactory = ValidationUtils.assertNotNull(jsonFactory, "JSONFactory"); } /** * @see HttpResponseHandler#handle(HttpResponse) */ public KscWebServiceResponse<T> handle(HttpResponse response) throws Exception { log.trace("Parsing service response JSON"); // TODOFIX String CRC32Checksum = response.getHeaders().get("x-amz-crc32"); CRC32ChecksumCalculatingInputStream crc32ChecksumInputStream = null; JsonParser jsonParser = null; if (shouldParsePayloadAsJson()) { if (CRC32Checksum != null) { crc32ChecksumInputStream = new CRC32ChecksumCalculatingInputStream(response.getContent()); jsonParser = jsonFactory.createParser(crc32ChecksumInputStream); } else { jsonParser = jsonFactory.createParser(response.getContent()); } } try { KscWebServiceResponse<T> awsResponse = new KscWebServiceResponse<T>(); JsonUnmarshallerContext unmarshallerContext = new JsonUnmarshallerContextImpl(jsonParser, simpleTypeUnmarshallers, response); registerAdditionalMetadataExpressions(unmarshallerContext); T result = responseUnmarshaller.unmarshall(unmarshallerContext); if (CRC32Checksum != null) { long serverSideCRC = Long.parseLong(CRC32Checksum); long clientSideCRC = crc32ChecksumInputStream.getCRC32Checksum(); if (clientSideCRC != serverSideCRC) { throw new CRC32MismatchException( "Client calculated crc32 checksum didn't match that calculated by server side"); } } awsResponse.setResult(result); Map<String, String> metadata = unmarshallerContext.getMetadata(); metadata.put(ResponseMetadata.KSC_REQUEST_ID, response.getHeaders().get(X_KSC_REQUEST_ID_HEADER)); awsResponse.setResponseMetadata(new ResponseMetadata(metadata)); log.trace("Done parsing service response"); return awsResponse; } finally { if (shouldParsePayloadAsJson()) { try { jsonParser.close(); } catch (IOException e) { log.warn("Error closing json parser", e); } } } } /** * Hook for subclasses to override in order to collect additional metadata from service * responses. * * @param unmarshallerContext * The unmarshaller context used to configure a service's response * data. */ protected void registerAdditionalMetadataExpressions(JsonUnmarshallerContext unmarshallerContext) { } public boolean needsConnectionLeftOpen() { return needsConnectionLeftOpen; } /** * @return True if the payload will be parsed as JSON, false otherwise. */ private boolean shouldParsePayloadAsJson() { return !needsConnectionLeftOpen && isPayloadJson; } }