WebDavExample.java

/**
 * Copyright (C) 2016 uphy.jp
 * 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.
 */

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import javax.net.ssl.HttpsURLConnection;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import java.io.IOException;
import java.lang.reflect.Field;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;


/**
 * @author Yuhi Ishikura
 */
public class WebDavExample {

  public static void main(String[] args) throws Throwable {
    final URL url = new URL("http://localhost:8000");
    final WebDavClient client = new WebDavClient();
    for (WebDavLink link : client.list(url)) {
      System.out.println(link);
    }
  }

  static class WebDavClient {

    List<WebDavLink> list(URL url) throws IOException {
      final HttpURLConnection con = (HttpURLConnection)url.openConnection();
      //con.setRequestMethod("PROPFIND"); // not supported
      setHttpRequestMethod(con, "PROPFIND");
      final List<WebDavLink> links = new ArrayList<>();
      try {
        final Document doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(con.getInputStream());
        final XPath xpath = XPathFactory.newInstance().newXPath();
        final NodeList responseList = (NodeList)xpath.evaluate("//multistatus/response", doc, XPathConstants.NODESET);
        for (int i = 0; i < responseList.getLength(); i++) {
          final Element response = (Element)responseList.item(i);
          final String href = (String)xpath.evaluate("href/text()", response, XPathConstants.STRING);
          final Element propstat = (Element)xpath.evaluate("propstat", response, XPathConstants.NODE);
          final Element prop = (Element)xpath.evaluate("prop", propstat, XPathConstants.NODE);
          final Element collectionResourceTypeNode = (Element)xpath.evaluate("resourcetype/collection", prop, XPathConstants.NODE);
          final String lastModified = (String)xpath.evaluate("getlastmodified/text()", prop, XPathConstants.STRING);
          final String status = (String)xpath.evaluate("status/text()", propstat, XPathConstants.STRING);

          final boolean isDirectory = collectionResourceTypeNode != null;
          if (isDirectory) {
            links.add(WebDavLink.createDirectory(url, href, lastModified, status));
          } else {
            final long contentLength = ((Number)xpath.evaluate("getcontentlength/text()", prop, XPathConstants.NUMBER)).longValue();
            final String contentType = (String)xpath.evaluate("getcontenttype/text()", prop, XPathConstants.STRING);
            links.add(WebDavLink.createFile(url, href, lastModified, status, contentType, contentLength));
          }
        }
      } catch (ParserConfigurationException e) {
        throw new IOException(e);
      } catch (IOException e) {
        throw new IOException(e);
      } catch (XPathExpressionException e) {
        throw new IOException(e);
      } catch (SAXException e) {
        throw new IOException(e);
      } finally {
        con.disconnect();
      }
      return links;
    }

    private static void setHttpRequestMethod(HttpURLConnection httpURLConnection, String method) {
      try {
        httpURLConnection.setRequestMethod(method);
      } catch (final ProtocolException pe) {
        try {
          final Class<?> httpURLConnectionClass = httpURLConnection
            .getClass();
          final Class<?> parentClass = httpURLConnectionClass
            .getSuperclass();
          final Field methodField;
          if (parentClass == HttpsURLConnection.class) {
            methodField = parentClass.getSuperclass().getDeclaredField(
              "method");
          } else {
            methodField = parentClass.getDeclaredField("method");
          }
          methodField.setAccessible(true);
          methodField.set(httpURLConnection, method);
        } catch (final Exception e) {
          throw new RuntimeException(e);
        }
      }
    }

  }

  static class WebDavLink {

    private URL parent;
    private String href;
    private String lastModified;
    private String status;
    private boolean directory;
    private long contentLength;
    private String contentType;

    static WebDavLink createDirectory(URL parent, String href, String lastModified, String status) {
      final WebDavLink link = new WebDavLink(parent, href, lastModified, status);
      link.directory = true;
      return link;
    }

    static WebDavLink createFile(URL parent, String href, String lastModified, String status, String contentType, long contentLength) {
      final WebDavLink link = new WebDavLink(parent, href, lastModified, status);
      link.directory = false;
      link.contentLength = contentLength;
      link.contentType = contentType;
      return link;
    }

    private WebDavLink(final URL parent, final String href, final String lastModified, final String status) {
      this.parent = parent;
      this.href = href;
      this.lastModified = lastModified;
      this.status = status;
    }

    public String getStatus() {
      return status;
    }

    public String getHref() {
      return href;
    }

    public URL getLink() {
      try {
        return new URL(this.parent, this.href);
      } catch (MalformedURLException e) {
        throw new RuntimeException(e);
      }
    }

    public String getLastModified() {
      return lastModified;
    }

    public boolean isDirectory() {
      return directory;
    }

    public long getContentLength() {
      return contentLength;
    }

    public String getContentType() {
      return contentType;
    }

    @Override
    public String toString() {
      return String.format("WebDavLink[href='%s', lastModified='%s', status='%s', directory=%s, contentLength=%d, contentType='%s']", href, lastModified, status, directory, contentLength, contentType);
    }
  }

}