RequestProcessor.java
/*
* Copyright (c) 2019, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
*
* WSO2 Inc. licenses this file to you 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.commons.emulator;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;
import org.xml.sax.helpers.DefaultHandler;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.Map;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
/**
* Class responsible for removing the unwanted whitespaces in any type of inputs.
*/
public class RequestProcessor {
RequestProcessor() {
}
private static Log log = LogFactory.getLog(RequestProcessor.class.getName());
/**
* Remove irrelevant whitespaces from the input string.
* If string is a XML or JSON reordered the structure of the string to normalize
*
* @param inputString string which needs to remove whitespaces
* @return trim string not include irrelevant whitespaces
*/
public static String trimStrings(String inputString) {
//trim the string
String trimedString = inputString.trim();
//remove CDATA tag from the string if exists
if (trimedString.startsWith("<![CDATA[")) {
trimedString = trimedString.substring(9);
int index = trimedString.indexOf("]]>");
if (index == -1) {
throw new IllegalStateException("argument starts with <![CDATA[ but cannot find pairing ]]>");
}
trimedString = trimedString.substring(0, index);
}
trimedString = convertStringToRelatedDocumentType(trimedString);
return trimedString.replaceAll("\\s", "");
}
/**
* Check the input string is a XML type and generate a XML object and convert it to string.
* Check the input string is a JSON type and generate a JSON object and convert it to string.
*
* @param domString inputString which about to convert
* @return reordered trim string not include irrelevant whitespaces
*/
private static String convertStringToRelatedDocumentType(String domString) {
//Parser that produces DOM object trees from XML content
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
//API to obtain DOM Document instance
DocumentBuilder builder;
String processedString;
try {
//Create DocumentBuilder with default configuration
builder = factory.newDocumentBuilder();
builder.setErrorHandler(new DefaultHandler());
//Parse the content to Document object
Document xmlDOM = builder.parse(new InputSource(new StringReader(domString)));
processedString = nodeToString(xmlDOM);
processedString = processedString.replaceAll("xmlns=\"\"", "");
} catch (Exception e) {
processedString = convertAsJSONString(domString);
}
return processedString;
}
/**
* Convert XML document to string.
*
* @param node document node which represent XML
* @return converted document element as a string
*/
private static String nodeToString(Node node) {
StringWriter stringWriter = new StringWriter();
try {
Transformer transformer = TransformerFactory.newInstance().newTransformer();
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.transform(new DOMSource(node), new StreamResult(stringWriter));
} catch (Exception e) {
log.error("nodeToString Transformer Exception", e);
}
return stringWriter.toString();
}
/**
* Create JSON object using input string.
* If failed return as it is.
*
* @param inputString input string which is not an XML
* @return reordered string
*/
private static String convertAsJSONString(String inputString) {
try {
Gson gson = new GsonBuilder()
.setPrettyPrinting()
.registerTypeAdapterFactory(new TreeMapTypeAdapterFactory())
.create();
Map root = gson.fromJson(inputString, Map.class);
return gson.toJson(root);
} catch (Exception e) {
return inputString;
}
}
}