org.neo4j.ogm.drivers.http.response.AbstractHttpResponse Maven / Gradle / Ivy

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/*
 * Copyright (c) 2002-2016 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This product is licensed to you under the Apache License, Version 2.0 (the "License").
 * You may not use this product except in compliance with the License.
 *
 * This product may include a number of subcomponents with
 * separate copyright notices and license terms. Your use of the source
 * code for these subcomponents is subject to the terms and
 *  conditions of the subcomponent's license, as noted in the LICENSE file.
 */

package org.neo4j.ogm.drivers.http.response;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.JsonToken;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.util.TokenBuffer;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.neo4j.ogm.exception.CypherException;
import org.neo4j.ogm.json.ObjectMapperFactory;
import org.neo4j.ogm.model.QueryStatistics;
import org.neo4j.ogm.response.model.QueryStatisticsModel;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

/**
 * @author vince
 * @author Luanne Misquitta
 */
public abstract class AbstractHttpResponse {

	private final InputStream results;
	private final JsonParser bufferParser;
	private final ObjectMapper mapper = ObjectMapperFactory.objectMapper();
	private final TokenBuffer buffer;
	private final Class resultClass;
	private final CloseableHttpResponse httpResponse;

	private String[] columns;
	private QueryStatistics queryStatistics;
	private JsonNode responseNode;

	private static final Logger LOGGER = LoggerFactory.getLogger( AbstractHttpResponse.class );

	public AbstractHttpResponse(CloseableHttpResponse httpResponse, Class resultClass) {

		this.resultClass = resultClass;
		try {
			this.httpResponse = httpResponse;
			this.results = httpResponse.getEntity().getContent();
			JsonParser parser = ObjectMapperFactory.jsonFactory().createParser(results);
			buffer = new TokenBuffer(parser);
			//Copy the contents of the response into the token buffer.
			//This is so that we do not have to serialize the response to textual json while we get to the end of the stream to check for errors
			parser.nextToken();
			buffer.copyCurrentStructure(parser);
			bufferParser = buffer.asParser();

		} catch (IOException ioException) {
			throw new RuntimeException(ioException);
		}
		finally {
			close(); //We are done with the InputStream
		}
		initialise();
	}

	private void initialise() {
		try {
			responseNode = mapper.readTree(buffer.asParser());
			JsonNode errors = responseNode.findValue("errors");
			if (errors.elements().hasNext()) {
				JsonNode errorNode = errors.elements().next();
				throw new CypherException("Error executing Cypher " + errorNode.findValue("code"), errorNode.findValue("code").asText(), errorNode.findValue("message").asText());
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	public T nextDataRecord(String key) {
		JsonToken token;
		try {
			while ((token = bufferParser.nextToken()) != null) {
				if (JsonToken.FIELD_NAME.equals(token)) {
					if (key.equals(bufferParser.getCurrentName())) {
						return mapper.readValue(bufferParser, resultClass);
					}
				}
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * Returns the first set of columns from the JSON response.
	 * Note that the current implementation expects that columns be standard across all statements in a Cypher transaction.
	 * @return the first set of columns from a JSON response
	 */
	public String[] columns() {
		if (columns == null) {
			List columnsList = new ArrayList<>();
			List columnsNodes = responseNode.findValues("columns");
			if (columnsNodes != null && columnsNodes.size() > 0) {
				JsonNode firstColumnsNode = columnsNodes.get(0);
				for (JsonNode columnNode : firstColumnsNode) {
					columnsList.add(columnNode.asText());
				}
				columns = new String[columnsList.size()];
				columns = columnsList.toArray(columns);
			}
		}
		return columns;
	}

	/**
	 * Extract stats from the response if present
	 * @return queryStatistics or null if the response does not contain it
	 */
	public QueryStatistics statistics() {
		if (queryStatistics ==null) {
			List statsNodes = responseNode.findValues("stats");
			try {
				if (statsNodes != null && statsNodes.size() > 0) {
					queryStatistics = mapper.treeToValue(statsNodes.get(0), QueryStatisticsModel.class);
				}
			} catch (JsonProcessingException jsonException) {
				throw new RuntimeException(jsonException);
			}
		}
		return queryStatistics;
	}

	private void close() {
		try {
			LOGGER.debug("Thread {}: Releasing HttpResponse", Thread.currentThread().getId());
			results.close();
			httpResponse.close();
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}
}