/*
* Copyright 2013-2017 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.regions;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
/**
* Parses a region metadata file to pull out information about the
* available regions, names, IDs, and what service endpoints are available
* in each region.
*/
public class RegionMetadataParser {
private static final String REGION_TAG = "Region";
private static final String REGION_ID_TAG = "Name";
private static final String DOMAIN_TAG = "Domain";
private static final String ENDPOINT_TAG = "Endpoint";
private static final String SERVICE_TAG = "ServiceName";
private static final String HTTP_TAG = "Http";
private static final String HTTPS_TAG = "Https";
private static final String HOSTNAME_TAG = "Hostname";
/**
* Parses the specified input stream and returns a {@code RegionMetadata}
* object.
*
* @param input the input stream to parse
* @return the parsed region metadata
* @throws IOException on error
*/
public static RegionMetadata parse(final InputStream input)
throws IOException {
return new RegionMetadata(internalParse(input, false));
}
/**
* @deprecated since this object is stateless
*/
@Deprecated
public RegionMetadataParser() {
}
/**
* Parses the specified input stream and returns a list of the regions
* declared in it. By default, verification on the region endpoints is
* disabled.
*
* @param input
* The stream containing the region metadata to parse.
*
* @return The list of parsed regions.
* @deprecated in favor of {@link #parse(InputStream)}
*/
@Deprecated
public List<Region> parseRegionMetadata(InputStream input)
throws IOException {
return internalParse(input, false);
}
/**
* Parses the specified input stream and optionally verifies that all of
* the endpoints end in ".amazonaws.com". This method is deprecated, since
* not all valid AWS endpoints end in ".amazonaws.com" any more.
*
* @param input
* The stream containing the region metadata to parse.
* @param endpointVerification
* Whether to verify each region endpoint
*
* @return The list of parsed regions.
* @deprecated in favor of {@link #parse(InputStream)}
*/
@Deprecated
public List<Region> parseRegionMetadata(final InputStream input,
final boolean endpointVerification)
throws IOException {
return internalParse(input, endpointVerification);
}
private static List<Region> internalParse(
final InputStream input,
final boolean endpointVerification) throws IOException {
Document document;
try {
DocumentBuilderFactory factory =
DocumentBuilderFactory.newInstance();
DocumentBuilder documentBuilder = factory.newDocumentBuilder();
document = documentBuilder.parse(input);
} catch (IOException exception) {
throw exception;
} catch (Exception exception) {
throw new IOException("Unable to parse region metadata file: "
+ exception.getMessage(),
exception);
} finally {
try {
input.close();
} catch (IOException exception) {
}
}
NodeList regionNodes = document.getElementsByTagName(REGION_TAG);
List<Region> regions = new ArrayList<Region>();
for (int i = 0; i < regionNodes.getLength(); i++) {
Node node = regionNodes.item(i);
if (node.getNodeType() == Node.ELEMENT_NODE) {
Element element = (Element)node;
regions.add(parseRegionElement(element, endpointVerification));
}
}
return regions;
}
private static Region parseRegionElement(
final Element regionElement,
final boolean endpointVerification) {
String name = getChildElementValue(REGION_ID_TAG, regionElement);
String domain = getChildElementValue(DOMAIN_TAG, regionElement);
InMemoryRegionImpl regionImpl = new InMemoryRegionImpl(name, domain);
NodeList endpointNodes =
regionElement.getElementsByTagName(ENDPOINT_TAG);
for (int i = 0; i < endpointNodes.getLength(); i++) {
addRegionEndpoint(regionImpl,
(Element) endpointNodes.item(i),
endpointVerification);
}
return new Region(regionImpl);
}
private static void addRegionEndpoint(
final InMemoryRegionImpl region,
final Element endpointElement,
final boolean endpointVerification) {
String serviceName = getChildElementValue(SERVICE_TAG, endpointElement);
String hostname = getChildElementValue(HOSTNAME_TAG, endpointElement);
String http = getChildElementValue(HTTP_TAG, endpointElement);
String https = getChildElementValue(HTTPS_TAG, endpointElement);
if ( endpointVerification && !verifyLegacyEndpoint(hostname) ) {
throw new IllegalStateException("Invalid service endpoint ("
+ hostname + ") is detected.");
}
region.addEndpoint(serviceName, hostname);
if (Boolean.valueOf(http)) {
region.addHttp(serviceName);
}
if (Boolean.valueOf(https)) {
region.addHttps(serviceName);
}
}
private static String getChildElementValue(
final String tagName,
final Element element) {
Node tagNode = element.getElementsByTagName(tagName).item(0);
if ( tagNode == null )
return null;
NodeList nodes= tagNode.getChildNodes();
Node node = (Node)nodes.item(0);
return node.getNodeValue();
}
/**
* Returns whether the provided endpoint is a "valid" AWS service endpoint
* ending in ".amazonaws.com".
*/
private static boolean verifyLegacyEndpoint(String endpoint) {
return endpoint.endsWith(".amazonaws.com");
}
}