/*
* Copyright 2012-2016 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://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.util;
import com.amazonaws.internal.config.HostRegexToRegionMapping;
import com.amazonaws.internal.config.InternalConfig;
import org.apache.commons.logging.LogFactory;
import java.net.InetAddress;
import java.net.URI;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class AwsHostNameUtils {
private static final Pattern S3_ENDPOINT_PATTERN =
Pattern.compile("^(?:.+\\.)?s3[.-]([a-z0-9-]+)$");
/**
* @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 == null) {
throw new IllegalArgumentException("hostname cannot be null");
}
String regionNameInInternalConfig = parseRegionNameByInternalConfig(host);
if (regionNameInInternalConfig != null) {
return regionNameInInternalConfig;
}
if (host.endsWith(".amazonaws.com")) {
int index = host.length() - ".amazonaws.com".length();
return parseStandardRegionName(host.substring(0, index));
}
if (serviceHint != null) {
// 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) {
Matcher matcher = S3_ENDPOINT_PATTERN.matcher(fragment);
if (matcher.matches()) {
// host was 'bucket.s3-[region].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;
}
/**
* @return the configured region name if the given host name matches any of
* the host-to-region mappings in the internal config; otherwise
* return null.
*/
private static String parseRegionNameByInternalConfig(String host) {
InternalConfig internConfig = InternalConfig.Factory.getInternalConfig();
for (HostRegexToRegionMapping mapping : internConfig.getHostRegexToRegionMappings()) {
String hostNameRegex = mapping.getHostNameRegex();
if (host.matches(hostNameRegex)) {
return mapping.getRegionName();
}
}
return null;
}
/**
* 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";
}
}
}