/*
* Copyright (c) 2015, WSO2 Inc. (http://www.wso2.org) 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.
* You may obtain a copy of the License at
*
* http://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 org.apache.synapse.util.xpath;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jaxen.Context;
import org.jaxen.Function;
import org.jaxen.FunctionCallException;
import org.jaxen.function.StringFunction;
import java.io.UnsupportedEncodingException;
import java.util.List;
/**
* Implements the XPath extension function synapse:base64Decode(string)
*/
public class Base64DecodeFunction implements Function {
private static final Log log = LogFactory.getLog(Base64DecodeFunction.class);
public static final String NULL_STRING = "";
private static final String DEFAULT_CHARSET = "UTF-8";
public Object call(Context context, List args) throws FunctionCallException {
if (args == null || args.size() == 0) {
if (log.isDebugEnabled()) {
log.debug("Property key value for lookup is not specified");
}
return NULL_STRING;
}
int size = args.size();
if (size == 1) {
// get the first argument, it can be a function returning a string as well
String encodedValue = StringFunction.evaluate(args.get(0), context.getNavigator());
// use the default UTF-8 decoding.
return decode(log.isDebugEnabled(), DEFAULT_CHARSET, encodedValue);
} else if (size == 2) {
// get the first argument, it can be a function returning a string as well
String encodedValue = StringFunction.evaluate(args.get(0), context.getNavigator());
// charset is in the second argument
String charset = StringFunction.evaluate(args.get(1), context.getNavigator());
return decode(log.isDebugEnabled(), charset, encodedValue);
} else {
if (log.isDebugEnabled()) {
log.debug("base64Decode function expects only two arguments maximum, returning empty string");
}
}
// return empty string if the arguments are wrong
return NULL_STRING;
}
private Object decode(boolean debugOn, String charset, String value)
throws FunctionCallException {
if (value == null || value.isEmpty()) {
if (debugOn) {
log.debug("Non empty string value should be provided for decode");
}
return NULL_STRING;
}
byte[] decodedValue;
try {
decodedValue = new Base64().decode(value.getBytes(charset));
} catch (UnsupportedEncodingException e) {
String msg = "Unsupported Charset";
log.error(msg, e);
throw new FunctionCallException(msg, e);
}
String decodedString;
try {
decodedString = new String(decodedValue, charset).trim();
} catch (UnsupportedEncodingException e) {
String msg = "Unsupported Charset";
log.error(msg, e);
throw new FunctionCallException(msg, e);
}
if (debugOn) {
log.debug("Decoded base64 encoded value: " + value + " with charset: " + charset +
" to String: " + decodedString);
}
return decodedString;
}
}