/*

 * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.security.timestamp;

import java.io.BufferedInputStream;

import java.io.DataOutputStream;

import java.io.EOFException;

import java.io.IOException;

import java.net.URI;

import java.net.URL;

import java.net.HttpURLConnection;

import java.util.*;

import sun.security.util.Debug;

/**

 * A timestamper that communicates with a Timestamping Authority (TSA)

 * over HTTP.

 * It supports the Time-Stamp Protocol defined in:

 * <a href="http://www.ietf.org/rfc/rfc3161.txt">RFC 3161</a>.

 *

 * @since 1.5

 * @author Vincent Ryan

 */

public class HttpTimestamper implements Timestamper {

    private static final int CONNECT_TIMEOUT = 15000; // 15 seconds

    // The MIME type for a timestamp query

    private static final String TS_QUERY_MIME_TYPE =

        "application/timestamp-query";

    // The MIME type for a timestamp reply

    private static final String TS_REPLY_MIME_TYPE =

        "application/timestamp-reply";

    private static final Debug debug = Debug.getInstance("ts");

    /*

     * HTTP URI identifying the location of the TSA

     */

    private URI tsaURI = null;

    /**

     * Creates a timestamper that connects to the specified TSA.

     *

     * @param tsaURI The location of the TSA. It must be an HTTP or HTTPS URI.

     * @throws IllegalArgumentException if tsaURI is not an HTTP or HTTPS URI

     */

    public HttpTimestamper(URI tsaURI) {

        if (!tsaURI.getScheme().equalsIgnoreCase("http") &&

                !tsaURI.getScheme().equalsIgnoreCase("https")) {

            throw new IllegalArgumentException(

                    "TSA must be an HTTP or HTTPS URI");

        }

        this.tsaURI = tsaURI;

    }

    /**

     * Connects to the TSA and requests a timestamp.

     *

     * @param tsQuery The timestamp query.

     * @return The result of the timestamp query.

     * @throws IOException The exception is thrown if a problem occurs while

     *         communicating with the TSA.

     */

    public TSResponse generateTimestamp(TSRequest tsQuery) throws IOException {

        HttpURLConnection connection =

            (HttpURLConnection) tsaURI.toURL().openConnection();

        connection.setDoOutput(true);

        connection.setUseCaches(false); // ignore cache

        connection.setRequestProperty("Content-Type", TS_QUERY_MIME_TYPE);

        connection.setRequestMethod("POST");

        // Avoids the "hang" when a proxy is required but none has been set.

        connection.setConnectTimeout(CONNECT_TIMEOUT);

        if (debug != null) {

            Set<Map.Entry<String, List<String>>> headers =

                connection.getRequestProperties().entrySet();

            debug.println(connection.getRequestMethod() + " " + tsaURI +

                " HTTP/1.1");

            for (Map.Entry<String, List<String>> e : headers) {

                debug.println("  " + e);

            }

            debug.println();

        }

        connection.connect(); // No HTTP authentication is performed

        // Send the request

        DataOutputStream output = null;

        try {

            output = new DataOutputStream(connection.getOutputStream());

            byte[] request = tsQuery.encode();

            output.write(request, 0, request.length);

            output.flush();

            if (debug != null) {

                debug.println("sent timestamp query (length=" +

                        request.length + ")");

            }

        } finally {

            if (output != null) {

                output.close();

            }

        }

        // Receive the reply

        BufferedInputStream input = null;

        byte[] replyBuffer = null;

        try {

            input = new BufferedInputStream(connection.getInputStream());

            if (debug != null) {

                String header = connection.getHeaderField(0);

                debug.println(header);

                int i = 1;

                while ((header = connection.getHeaderField(i)) != null) {

                    String key = connection.getHeaderFieldKey(i);

                    debug.println("  " + ((key==null) ? "" : key + ": ") +

                        header);

                    i++;

                }

                debug.println();

            }

            verifyMimeType(connection.getContentType());

            int clen = connection.getContentLength();

            replyBuffer = input.readAllBytes();

            if (clen != -1 && replyBuffer.length != clen)

                throw new EOFException("Expected:" + clen +

                                       ", read:" + replyBuffer.length);

            if (debug != null) {

                debug.println("received timestamp response (length=" +

                        replyBuffer.length + ")");

            }

        } finally {

            if (input != null) {

                input.close();

            }

        }

        return new TSResponse(replyBuffer);

    }

    /*

     * Checks that the MIME content type is a timestamp reply.

     *

     * @param contentType The MIME content type to be checked.

     * @throws IOException The exception is thrown if a mismatch occurs.

     */

    private static void verifyMimeType(String contentType) throws IOException {

        if (! TS_REPLY_MIME_TYPE.equalsIgnoreCase(contentType)) {

            throw new IOException("MIME Content-Type is not " +

                TS_REPLY_MIME_TYPE);

        }

    }

}