com.google.apphosting.utils.config.DosXmlReader Maven / Gradle / Ivy
/*
* Copyright 2021 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://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 com.google.apphosting.utils.config;
import java.io.InputStream;
import org.w3c.dom.Element;
/**
* Creates an {@link DosXml} instance from
* WEB-INF/dos.xml. If you want to read the configuration
* from a different file, subclass and override {@link #getFilename()}. If you
* want to read the configuration from something that isn't a file, subclass
* and override {@link #getInputStream()}.
*
*/
public class DosXmlReader extends AbstractConfigXmlReader {
// N.B.: this class is not currently used in, and
// therefore has not been tested in, the runtime. Before adding a
// dependency on this code from the runtime please ensure that there
// is no possibility for external entity references or other
// dependencies that may cause it to fail when running under the
// restricted environment
// Relative location of the config file
private static final String FILENAME = "WEB-INF/dos.xml";
// XML Constants
private static final String DENYLISTENTRIES_TAG = "blacklistentries";
private static final String DENYLIST_TAG = "blacklist";
private static final String DESCRIPTION_TAG = "description";
private static final String SUBNET_TAG = "subnet";
/**
* Constructs the reader for {@code dos.xml} in a given application directory.
* @param appDir the application directory
*/
public DosXmlReader(String appDir) {
super(appDir, false);
}
@Override
protected String getRelativeFilename() {
return FILENAME;
}
/**
* Parses the config file.
* @return A {@link DosXml} object representing the parsed configuration.
*/
public DosXml readDosXml() {
return readConfigXml();
}
@Override
protected DosXml processXml(InputStream is) {
DosXml dosXml = new DosXml();
Element root = XmlUtils.parseXml(is).getDocumentElement();
if (!root.getTagName().equals(DENYLISTENTRIES_TAG)) {
throw new AppEngineConfigException(getFilename() + " does not contain <"
+ DENYLISTENTRIES_TAG + ">");
}
for (Element child : XmlUtils.getChildren(root)) {
if (child.getTagName().equals(DENYLIST_TAG)) {
parseDenylist(child, dosXml.addNewBlacklistEntry());
} else {
throw new AppEngineConfigException(getFilename() + " contains <"
+ child.getTagName() + "> instead of <" + DENYLIST_TAG + "/>");
}
}
dosXml.validateLastEntry();
return dosXml;
}
private void parseDenylist(Element denylistElement, DosXml.BlacklistEntry denylistEntry) {
for (Element child : XmlUtils.getChildren(denylistElement)) {
switch (child.getTagName()) {
case DESCRIPTION_TAG:
denylistEntry.setDescription(stringContents(child));
break;
case SUBNET_TAG:
denylistEntry.setSubnet(stringContents(child));
break;
default:
throw new AppEngineConfigException(getFilename() + " contains unknown <"
+ child.getTagName() + "> inside <" + DENYLIST_TAG + "/>");
}
}
}
}