mdretrieval.FileFetcher.java Source code

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Here is the source code for mdretrieval.FileFetcher.java

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//------------------------------------------------------------------------------
//
// Project: OBEOS METADATA EDITOR
// Authors: Natascha Neumaerker, Siemens Convergence Creators, Prague (CZ)
//          Milan Novacek, Siemens Convergence Creators, Prague (CZ)
//          Radim Zajonc, Siemens Convergence Creators, Prague (CZ)
//          Stanislav Kascak, Siemens Convergence Creators
//          
//------------------------------------------------------------------------------
// Copyright (C) 2017 Siemens Convergence Creators, Prague (CZ)
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies of this Software or works derived from this Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//------------------------------------------------------------------------------

package mdretrieval;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.InetSocketAddress;
import java.net.MalformedURLException;
import java.net.Proxy;
import java.net.URL;

import org.apache.commons.io.IOUtils;

import global.GUIrefs;
import global.Master;
import global.ServerConstants;
import utilities.StringUtilities;

public class FileFetcher {
    private static String HTTP_RDFXML_PROP = "application/rdf+xml";

    public static InputStream fetchFileFromUrl(String urlString) {

        InputStream inputStream = null;

        Proxy proxy = ServerConstants.isProxyEnabled
                ? new Proxy(Proxy.Type.HTTP, new InetSocketAddress(ServerConstants.hostname, ServerConstants.port))
                : Proxy.NO_PROXY;

        URL url;
        try {
            url = new URL(urlString);
            url.openConnection();

            if (proxy != Proxy.NO_PROXY && proxy.type() != Proxy.Type.DIRECT) {
                inputStream = url.openConnection(proxy).getInputStream();
            } else {
                inputStream = url.openConnection().getInputStream();
            }
        } catch (MalformedURLException e) {
            GUIrefs.displayAlert("Invalid URL " + urlString + "- \\n malformed expression");
            e.printStackTrace();
            inputStream = null;
        } catch (IOException ioe) {
            GUIrefs.displayAlert("Cannot read from " + StringUtilities.escapeQuotes(urlString) + "- IOException");
            ioe.printStackTrace();
            inputStream = null;
        }

        return inputStream;
    }

    public static String[] loadStringFromURL(String destinationURL, boolean acceptRDF) throws IOException {
        String[] ret = new String[2];

        HttpURLConnection urlConnection = null;
        InputStream inputStream = null;

        String dest = destinationURL;
        URL url = new URL(dest);
        Proxy proxy = null;

        if (ServerConstants.isProxyEnabled) {
            proxy = new Proxy(Proxy.Type.HTTP,
                    new InetSocketAddress(ServerConstants.hostname, ServerConstants.port));
            urlConnection = (HttpURLConnection) url.openConnection(proxy);
        } else {
            urlConnection = (HttpURLConnection) url.openConnection();
        }

        boolean redirect = false;

        int status = urlConnection.getResponseCode();
        if (Master.DEBUG_LEVEL >= Master.LOW)
            System.out.println("RESPONSE-CODE--> " + status);
        if (status != HttpURLConnection.HTTP_OK) {
            if (status == HttpURLConnection.HTTP_MOVED_TEMP || status == HttpURLConnection.HTTP_MOVED_PERM
                    || status == HttpURLConnection.HTTP_SEE_OTHER)
                redirect = true;
        }

        if (redirect) {
            String newUrl = urlConnection.getHeaderField("Location");
            dest = newUrl;
            urlConnection.disconnect();
            if (Master.DEBUG_LEVEL > Master.LOW)
                System.out.println("REDIRECT--> " + newUrl);
            urlConnection = openMaybeProxyConnection(proxy, newUrl);
        }

        try {
            urlConnection.setRequestMethod("GET");
            urlConnection.setRequestProperty("Accept", HTTP_RDFXML_PROP);
            urlConnection.setDoInput(true);
            //urlConnection.setDoOutput(true);            
            inputStream = urlConnection.getInputStream();
            ret[1] = urlConnection.getHeaderField("Content-Type");
        } catch (IllegalStateException e) {
            if (Master.DEBUG_LEVEL >= Master.LOW)
                System.out.println(" DEBUG: IllegalStateException");
            urlConnection.disconnect();
            HttpURLConnection conn2 = openMaybeProxyConnection(proxy, dest);
            conn2.setRequestMethod("GET");
            conn2.setRequestProperty("Accept", HTTP_RDFXML_PROP);
            conn2.setDoInput(true);
            inputStream = conn2.getInputStream();
            ret[1] = conn2.getHeaderField("Content-Type");
        }

        try {
            ret[0] = IOUtils.toString(inputStream);

            if (Master.DEBUG_LEVEL > Master.LOW) {
                System.out.println(" Content-type: " + urlConnection.getHeaderField("Content-Type"));
            }
        } finally {
            IOUtils.closeQuietly(inputStream);
            urlConnection.disconnect();
        }

        if (Master.DEBUG_LEVEL > Master.LOW)
            System.out.println("Done reading " + destinationURL);
        return ret;

    }

    private static HttpURLConnection openMaybeProxyConnection(Proxy proxy, String dest)
            throws MalformedURLException, IOException {
        return proxy != null ? (HttpURLConnection) new URL(dest).openConnection(proxy)
                : (HttpURLConnection) new URL(dest).openConnection();
    }
}