Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License 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 org.apache.streams.components.http.persist; import org.apache.streams.components.http.HttpPersistWriterConfiguration; import org.apache.streams.config.ComponentConfigurator; import org.apache.streams.config.StreamsConfigurator; import org.apache.streams.core.StreamsDatum; import org.apache.streams.core.StreamsPersistWriter; import org.apache.streams.jackson.StreamsJacksonMapper; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.node.ObjectNode; import org.apache.commons.codec.binary.Base64; import org.apache.commons.lang3.StringUtils; import org.apache.http.HttpEntity; import org.apache.http.HttpStatus; import org.apache.http.client.methods.CloseableHttpResponse; import org.apache.http.client.methods.HttpPost; import org.apache.http.client.utils.URIBuilder; import org.apache.http.entity.StringEntity; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; import org.apache.http.util.EntityUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.net.URI; import java.net.URISyntaxException; import java.util.HashMap; import java.util.Map; import java.util.Objects; public class SimpleHTTPPostPersistWriter implements StreamsPersistWriter { private static final String STREAMS_ID = "SimpleHTTPPostPersistWriter"; private static final Logger LOGGER = LoggerFactory.getLogger(SimpleHTTPPostPersistWriter.class); protected ObjectMapper mapper; protected URIBuilder uriBuilder; protected CloseableHttpClient httpclient; protected HttpPersistWriterConfiguration configuration; protected String authHeader; public SimpleHTTPPostPersistWriter() { this(new ComponentConfigurator<>(HttpPersistWriterConfiguration.class) .detectConfiguration(StreamsConfigurator.getConfig().getConfig("http"))); } public SimpleHTTPPostPersistWriter(HttpPersistWriterConfiguration configuration) { this.configuration = configuration; } @Override public String getId() { return STREAMS_ID; } @Override public void write(StreamsDatum entry) { ObjectNode payload; try { payload = preparePayload(entry); } catch (Exception ex) { LOGGER.warn("Exception preparing payload, using empty payload"); payload = mapper.createObjectNode(); } Map<String, String> params = prepareParams(entry); URI uri = prepareURI(params); HttpPost httppost = prepareHttpPost(uri, payload); ObjectNode result = executePost(httppost); try { LOGGER.debug(mapper.writeValueAsString(result)); } catch (JsonProcessingException ex) { LOGGER.warn("Non-json response", ex.getMessage()); } } /** Override this to alter request URI. */ protected URI prepareURI(Map<String, String> params) { URI uri = null; for (Map.Entry<String, String> param : params.entrySet()) { uriBuilder = uriBuilder.setParameter(param.getKey(), param.getValue()); } try { uri = uriBuilder.build(); } catch (URISyntaxException ex) { LOGGER.error("URI error {}", uriBuilder.toString()); } return uri; } /** Override this to add parameters to the request. */ protected Map<String, String> prepareParams(StreamsDatum entry) { return new HashMap<>(); } /** Override this to alter json payload on to the request. */ protected ObjectNode preparePayload(StreamsDatum entry) throws Exception { if (entry.getDocument() != null) { if (entry.getDocument() instanceof ObjectNode) { return (ObjectNode) entry.getDocument(); } else { return mapper.convertValue(entry.getDocument(), ObjectNode.class); } } else { return null; } } /** Override this to add headers to the request. */ public HttpPost prepareHttpPost(URI uri, ObjectNode payload) { HttpPost httppost = new HttpPost(uri); httppost.addHeader("content-type", this.configuration.getContentType()); httppost.addHeader("accept-charset", "UTF-8"); if (StringUtils.isNotBlank(authHeader)) { httppost.addHeader("Authorization", "Basic " + authHeader); } try { String entity = mapper.writeValueAsString(payload); httppost.setEntity(new StringEntity(entity)); } catch (JsonProcessingException | UnsupportedEncodingException ex) { LOGGER.warn(ex.getMessage()); } return httppost; } protected ObjectNode executePost(HttpPost httpPost) { Objects.requireNonNull(httpPost); ObjectNode result = null; CloseableHttpResponse response = null; String entityString; try { response = httpclient.execute(httpPost); HttpEntity entity = response.getEntity(); // TODO: handle retry if (response.getStatusLine() != null && response.getStatusLine().getStatusCode() >= HttpStatus.SC_OK && entity != null) { entityString = EntityUtils.toString(entity); result = mapper.readValue(entityString, ObjectNode.class); } } catch (IOException ex) { LOGGER.error("IO error:\n{}\n{}\n{}", httpPost.toString(), response, ex.getMessage()); } finally { try { if (response != null) { response.close(); } } catch (IOException ignored) { LOGGER.trace("IOException", ignored); } } return result; } @Override public void prepare(Object configurationObject) { mapper = StreamsJacksonMapper.getInstance(); uriBuilder = new URIBuilder().setScheme(this.configuration.getProtocol()) .setHost(this.configuration.getHostname()).setPort(this.configuration.getPort().intValue()) .setPath(this.configuration.getResourcePath()); if (StringUtils.isNotBlank(configuration.getAccessToken())) { uriBuilder = uriBuilder.addParameter("access_token", configuration.getAccessToken()); } if (StringUtils.isNotBlank(configuration.getUsername()) && StringUtils.isNotBlank(configuration.getPassword())) { String string = configuration.getUsername() + ":" + configuration.getPassword(); authHeader = Base64.encodeBase64String(string.getBytes()); } httpclient = HttpClients.createDefault(); } @Override public void cleanUp() { LOGGER.info("shutting down SimpleHTTPPostPersistWriter"); try { httpclient.close(); } catch (IOException ex) { LOGGER.error(ex.getMessage()); } finally { try { httpclient.close(); } catch (IOException e2) { LOGGER.error(e2.getMessage()); } finally { httpclient = null; } } } }