Java example source code file (Request.java)

This example Java source code file (Request.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

action, charset, get, head, host, illegalargumentexception, malformedrequestexception, net, network, nio, pattern, post, put, regex, request, string, uri, us\-ascii

The Request.java Java example source code

/*
 * Copyright (c) 2004, 2011, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This source code is provided to illustrate the usage of a given feature
 * or technique and has been deliberately simplified. Additional steps
 * required for a production-quality application, such as security checks,
 * input validation and proper error handling, might not be present in
 * this sample code.
 */


import java.net.*;
import java.nio.*;
import java.nio.charset.*;
import java.util.regex.*;

/**
 * An encapsulation of the request received.
 * <P>
 * The static method parse() is responsible for creating this
 * object.
 *
 * @author Mark Reinhold
 * @author Brad R. Wetmore
 */
class Request {

    /**
     * A helper class for parsing HTTP command actions.
     */
    static class Action {

        private String name;
        private Action(String name) { this.name = name; }
        public String toString() { return name; }

        static Action GET = new Action("GET");
        static Action PUT = new Action("PUT");
        static Action POST = new Action("POST");
        static Action HEAD = new Action("HEAD");

        static Action parse(String s) {
            if (s.equals("GET"))
                return GET;
            if (s.equals("PUT"))
                return PUT;
            if (s.equals("POST"))
                return POST;
            if (s.equals("HEAD"))
                return HEAD;
            throw new IllegalArgumentException(s);
        }
    }

    private Action action;
    private String version;
    private URI uri;

    Action action() { return action; }
    String version() { return version; }
    URI uri() { return uri; }

    private Request(Action a, String v, URI u) {
        action = a;
        version = v;
        uri = u;
    }

    public String toString() {
        return (action + " " + version + " " + uri);
    }

    static boolean isComplete(ByteBuffer bb) {
        int p = bb.position() - 4;
        if (p < 0)
            return false;
        return (((bb.get(p + 0) == '\r') &&
                 (bb.get(p + 1) == '\n') &&
                 (bb.get(p + 2) == '\r') &&
                 (bb.get(p + 3) == '\n')));
    }

    private static Charset ascii = Charset.forName("US-ASCII");

    /*
     * The expected message format is first compiled into a pattern,
     * and is then compared against the inbound character buffer to
     * determine if there is a match.  This convienently tokenizes
     * our request into usable pieces.
     *
     * This uses Matcher "expression capture groups" to tokenize
     * requests like:
     *
     *     GET /dir/file HTTP/1.1
     *     Host: hostname
     *
     * into:
     *
     *     group[1] = "GET"
     *     group[2] = "/dir/file"
     *     group[3] = "1.1"
     *     group[4] = "hostname"
     *
     * The text in between the parens are used to captured the regexp text.
     */
    private static Pattern requestPattern
        = Pattern.compile("\\A([A-Z]+) +([^ ]+) +HTTP/([0-9\\.]+)$"
                          + ".*^Host: ([^ ]+)$.*\r\n\r\n\\z",
                          Pattern.MULTILINE | Pattern.DOTALL);

    static Request parse(ByteBuffer bb) throws MalformedRequestException {

        CharBuffer cb = ascii.decode(bb);
        Matcher m = requestPattern.matcher(cb);
        if (!m.matches())
            throw new MalformedRequestException();
        Action a;
        try {
            a = Action.parse(m.group(1));
        } catch (IllegalArgumentException x) {
            throw new MalformedRequestException();
        }
        URI u;
        try {
            u = new URI("http://"
                        + m.group(4)
                        + m.group(2));
        } catch (URISyntaxException x) {
            throw new MalformedRequestException();
        }
        return new Request(a, m.group(3), u);
    }
}