com.predic8.membrane.core.interceptor.authentication.xen.XenMessageContext Maven / Gradle / Ivy

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/* Copyright 2019 predic8 GmbH, www.predic8.com

   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 com.predic8.membrane.core.interceptor.authentication.xen;

import com.predic8.membrane.core.exchange.Exchange;
import com.predic8.membrane.core.http.Body;
import com.predic8.membrane.core.http.Message;
import com.predic8.membrane.core.interceptor.Interceptor;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

public class XenMessageContext {

    private static DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    private Exchange exchange;
    private Document doc;
    private Interceptor.Flow flow;
    private static String KEY = "xenMessageContext";

    public static XenMessageContext get(Exchange exchange, Interceptor.Flow flow) {
        XenMessageContext xmc = (XenMessageContext) exchange.getProperty(KEY + flow.toString());
        if (xmc != null)
            return xmc;

        Document document;

        synchronized (dbf) {
            try {
                document = dbf.newDocumentBuilder().parse(getMessage(exchange, flow).getBodyAsStream());
            } catch (SAXException e) {
                throw new RuntimeException(e);
            } catch (IOException e) {
                throw new RuntimeException(e);
            } catch (ParserConfigurationException e) {
                throw new RuntimeException(e);
            }
        }

        xmc = new XenMessageContext(exchange, document, flow);
        exchange.setProperty(KEY, xmc);
        return xmc;
    }

    private static Message getMessage(Exchange exchange, Interceptor.Flow flow) {
        switch (flow) {
            case RESPONSE:
                return exchange.getResponse();
            case REQUEST:
                return exchange.getRequest();
            default:
                throw new RuntimeException("not implemented");
        }
    }

    private XenMessageContext(Exchange exchange, Document doc, Interceptor.Flow flow) {
        this.exchange = exchange;
        this.doc = doc;
        this.flow = flow;
    }

    public Document getDocument() {
        return doc;
    }

    public void writeBack() {
        try {
            Transformer t = TransformerFactory.newInstance().newTransformer();

            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            t.transform(new DOMSource(doc), new StreamResult(baos));
            getMessage(exchange, flow).setBodyContent(baos.toByteArray());
        } catch (TransformerException e) {
            throw new RuntimeException(e);
        }
    }

    public void setX(XPath xp, String xPath, String value) throws XPathExpressionException {
        XPathExpression xp3 = xp.compile(xPath);
        NodeList ns = (NodeList) xp3.evaluate(getDocument(), XPathConstants.NODESET);

        if (ns.getLength() != 1)
            throw new RuntimeException("XPath returned nodeset with length != 1.");

        ns.item(0).setTextContent(value);
    }

}