Java tutorial
/** * Copyright (c) 2010-2015, openHAB.org and others. * * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html */ package org.openhab.binding.nest.internal.messages; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStream; import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.Properties; import java.util.TimeZone; import java.util.zip.GZIPInputStream; import java.util.zip.InflaterInputStream; import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler; import org.apache.commons.httpclient.Header; import org.apache.commons.httpclient.HeaderElement; import org.apache.commons.httpclient.HttpClient; import org.apache.commons.httpclient.HttpException; import org.apache.commons.httpclient.HttpMethod; import org.apache.commons.httpclient.HttpStatus; import org.apache.commons.httpclient.URIException; import org.apache.commons.httpclient.methods.EntityEnclosingMethod; import org.apache.commons.httpclient.methods.InputStreamRequestEntity; import org.apache.commons.httpclient.params.HttpMethodParams; import org.apache.commons.io.IOUtils; import org.codehaus.jackson.map.JsonMappingException; import org.codehaus.jackson.map.ObjectMapper; import org.codehaus.jackson.map.annotate.JsonSerialize.Inclusion; import org.openhab.binding.nest.internal.NestException; import org.openhab.io.net.http.HttpUtil; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Base class for all Nest API requests. * * @author John Cocula * @since 1.7.0 */ public abstract class AbstractRequest extends AbstractMessage implements Request { private static final Logger logger = LoggerFactory.getLogger(AbstractRequest.class); private static final Properties HTTP_HEADERS; private static final int HTTP_REQUEST_TIMEOUT = 10000; protected static final String HTTP_GET = "GET"; protected static final String HTTP_POST = "POST"; protected static final String HTTP_PUT = "PUT"; protected static final String API_BASE_URL = "https://developer-api.nest.com/"; protected static final ObjectMapper JSON = new ObjectMapper(); static { HTTP_HEADERS = new Properties(); HTTP_HEADERS.put("Accept", "application/json"); // do not serialize null values JSON.setSerializationInclusion(Inclusion.NON_NULL); // dates in the JSON are in ISO 8601 format TimeZone tz = TimeZone.getTimeZone("UTC"); DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"); df.setTimeZone(tz); JSON.setDateFormat(df); } protected final RuntimeException newException(final String message, final Exception cause, final String url, final String json) { if (cause instanceof JsonMappingException) { return new NestException("Could not parse JSON from URL '" + url + "': " + json, cause); } return new NestException(message, cause); } /** * Executes the given <code>url</code> with the given <code>httpMethod</code>. In the case of httpMethods that do * not support automatic redirection, manually handle the HTTP temporary redirect (307) and retry with the new URL. * * @param httpMethod * the HTTP method to use * @param url * the url to execute (in milliseconds) * @param contentString * the content to be sent to the given <code>url</code> or <code>null</code> if no content should be * sent. * @param contentType * the content type of the given <code>contentString</code> * @return the response body or <code>NULL</code> when the request went wrong */ protected final String executeUrl(final String httpMethod, final String url, final String contentString, final String contentType) { HttpClient client = new HttpClient(); HttpMethod method = HttpUtil.createHttpMethod(httpMethod, url); method.getParams().setSoTimeout(HTTP_REQUEST_TIMEOUT); method.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler(3, false)); for (String httpHeaderKey : HTTP_HEADERS.stringPropertyNames()) { method.addRequestHeader(new Header(httpHeaderKey, HTTP_HEADERS.getProperty(httpHeaderKey))); } // add content if a valid method is given ... if (method instanceof EntityEnclosingMethod && contentString != null) { EntityEnclosingMethod eeMethod = (EntityEnclosingMethod) method; InputStream content = new ByteArrayInputStream(contentString.getBytes()); eeMethod.setRequestEntity(new InputStreamRequestEntity(content, contentType)); } if (logger.isDebugEnabled()) { try { logger.trace("About to execute '" + method.getURI().toString() + "'"); } catch (URIException e) { logger.trace(e.getMessage()); } } try { int statusCode = client.executeMethod(method); if (statusCode == HttpStatus.SC_NO_CONTENT || statusCode == HttpStatus.SC_ACCEPTED) { // perfectly fine but we cannot expect any answer... return null; } // Manually handle 307 redirects with a little tail recursion if (statusCode == HttpStatus.SC_TEMPORARY_REDIRECT) { Header[] headers = method.getResponseHeaders("Location"); String newUrl = headers[headers.length - 1].getValue(); return executeUrl(httpMethod, newUrl, contentString, contentType); } if (statusCode != HttpStatus.SC_OK) { logger.warn("Method failed: " + method.getStatusLine()); } InputStream tmpResponseStream = method.getResponseBodyAsStream(); Header encodingHeader = method.getResponseHeader("Content-Encoding"); if (encodingHeader != null) { for (HeaderElement ehElem : encodingHeader.getElements()) { if (ehElem.toString().matches(".*gzip.*")) { tmpResponseStream = new GZIPInputStream(tmpResponseStream); logger.trace("GZipped InputStream from {}", url); } else if (ehElem.toString().matches(".*deflate.*")) { tmpResponseStream = new InflaterInputStream(tmpResponseStream); logger.trace("Deflated InputStream from {}", url); } } } String responseBody = IOUtils.toString(tmpResponseStream); if (!responseBody.isEmpty()) { logger.trace(responseBody); } return responseBody; } catch (HttpException he) { logger.error("Fatal protocol violation: {}", he.toString()); } catch (IOException ioe) { logger.error("Fatal transport error: {}", ioe.toString()); } finally { method.releaseConnection(); } return null; } }