Java tutorial
/* * Copyright 2012-2014 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://aws.amazon.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.amazonaws.utility; import java.net.InetAddress; import java.net.URI; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.apache.commons.logging.LogFactory; public class AwsHostNameUtils { private static final Pattern S3_ENDPOINT_PATTERN = Pattern.compile("^(?:.+\\.)?s3[.-]([a-z0-9-]+)$"); private static final Pattern STANDARD_CLOUDSEARCH_ENDPOINT_PATTERN = Pattern .compile("^(?:.+\\.)?([a-z0-9-]+)\\.cloudsearch$"); private static final Pattern EXTENDED_CLOUDSEARCH_ENDPOINT_PATTERN = Pattern .compile("^(?:.+\\.)?([a-z0-9-]+)\\.cloudsearch\\..+"); /** * @deprecated in favor of {@link #parseRegionName(String, String)}. */ @Deprecated public static String parseRegionName(URI endpoint) { return parseRegionName(endpoint.getHost(), null); } /** * Attempts to parse the region name from an endpoint based on conventions * about the endpoint format. * * @param host the hostname to parse * @param serviceHint an optional hint about the service for the endpoint * @return the region parsed from the hostname, or * "us-east-1" if no region information * could be found */ public static String parseRegionName(final String host, final String serviceHint) { if (host.endsWith(".amazonaws.com")) { int index = host.length() - ".amazonaws.com".length(); return parseStandardRegionName(host.substring(0, index)); } if (serviceHint != null) { if (serviceHint.equals("cloudsearch") && !host.startsWith("cloudsearch.")) { // CloudSearch domains use the nonstandard domain format // [domain].[region].cloudsearch.[suffix]. Matcher matcher = EXTENDED_CLOUDSEARCH_ENDPOINT_PATTERN.matcher(host); if (matcher.matches()) { return matcher.group(1); } } // If we have a service hint, look for 'service.[region]' or // 'service-[region]' in the endpoint's hostname. Pattern pattern = Pattern.compile("^(?:.+\\.)?" + Pattern.quote(serviceHint) + "[.-]([a-z0-9-]+)\\."); Matcher matcher = pattern.matcher(host); if (matcher.find()) { return matcher.group(1); } } // Endpoint is totally non-standard; guess us-east-1 for lack of a // better option. return "us-east-1"; } /** * Parses the region name from a standard (*.amazonaws.com) endpoint. * * @param fragment the portion of the endpoint excluding * ".amazonaws.com" * @return the parsed region name (or "us-east-1" as a * best guess if we can't tell for sure) */ private static String parseStandardRegionName(final String fragment) { if (fragment.endsWith(".s3") || fragment.endsWith(".s3-external-1")) { // host was 'bucket.s3.amazonaws.com' or 'bucket.s3-external-1.amazonaws.com', // which is us-east-1. return "us-east-1"; } Matcher matcher = S3_ENDPOINT_PATTERN.matcher(fragment); if (matcher.matches()) { // host was 'bucket.s3-[region].amazonaws.com'. return matcher.group(1); } matcher = STANDARD_CLOUDSEARCH_ENDPOINT_PATTERN.matcher(fragment); if (matcher.matches()) { // host was 'domain.[region].cloudsearch.amazonaws.com'. return matcher.group(1); } int index = fragment.lastIndexOf('.'); if (index == -1) { // host was 'service.amazonaws.com', guess us-east-1 // for lack of a better option. return "us-east-1"; } // host was 'service.[region].amazonaws.com'. String region = fragment.substring(index + 1); // Special case for iam.us-gov.amazonaws.com, which is actually // us-gov-west-1. if ("us-gov".equals(region)) { region = "us-gov-west-1"; } return region; } /** * Parses the service name from an endpoint. Can only handle endpoints of * the form 'service.[region.]amazonaws.com'. * * @deprecated because it's no longer needed by the SDK, and therefore not * maintained. */ @Deprecated public static String parseServiceName(URI endpoint) { String host = endpoint.getHost(); // If we don't recognize the domain, throw an exception. if (!host.endsWith(".amazonaws.com")) { throw new IllegalArgumentException( "Cannot parse a service name from an unrecognized endpoint (" + host + ")."); } String serviceAndRegion = host.substring(0, host.indexOf(".amazonaws.com")); // Special cases for S3 endpoints with bucket names embedded. if (serviceAndRegion.endsWith(".s3") || S3_ENDPOINT_PATTERN.matcher(serviceAndRegion).matches()) { return "s3"; } char separator = '.'; // If we don't detect a separator between service name and region, then // assume that the region is not included in the hostname, and it's only // the service name (ex: "http://iam.amazonaws.com"). if (serviceAndRegion.indexOf(separator) == -1) { return serviceAndRegion; } String service = serviceAndRegion.substring(0, serviceAndRegion.indexOf(separator)); return service; } /** * Returns the host name for the local host. If the operation is not allowed * by the security check, the textual representation of the IP address of * the local host is returned instead. If the ip address of the local host * cannot be resolved or if there is any other failure, "localhost" is * returned as a fallback. */ public static String localHostName() { try { InetAddress localhost = InetAddress.getLocalHost(); return localhost.getHostName(); } catch (Exception e) { LogFactory.getLog(AwsHostNameUtils.class) .debug("Failed to determine the local hostname; fall back to " + "use \"localhost\".", e); return "localhost"; } } }