connection.java

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/*
 * HttpURLConnection.java -- URLConnection class for HTTP protocol Copyright (C) 1998, 1999, 2000,
 * 2002, 2003 Free Software Foundation, Inc.
 * 
 * This file is part of GNU Classpath.
 * 
 * GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the
 * GNU General Public License as published by the Free Software Foundation; either version 2, or
 * (at your option) any later version.
 * 
 * GNU Classpath 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 for more details.
 * 
 * You should have received a copy of the GNU General Public License along with GNU Classpath; see
 * the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite
 * 330, Boston, MA 02111-1307 USA.
 * 
 * Linking this library statically or dynamically with other modules is making a combined work
 * based on this library. Thus, the terms and conditions of the GNU General Public License cover
 * the whole combination.
 * 
 * As a special exception, the copyright holders of this library give you permission to link this
 * library with independent modules to produce an executable, regardless of the license terms of
 * these independent modules, and to copy and distribute the resulting executable under terms of
 * your choice, provided that you also meet, for each linked independent module, the terms and
 * conditions of the license of that module. An independent module is a module which is not derived
 * from or based on this library. If you modify this library, you may extend this exception to your
 * version of the library, but you are not obligated to do so. If you do not wish to do so, delete
 * this
 */

package gnu.java.net.protocol.http;

import gnu.java.net.HeaderFieldHelper;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.ProtocolException;
import java.net.Socket;
import java.net.URL;
import java.util.Iterator;
import java.util.Map;

/**
 * This subclass of java.net.URLConnection models a URLConnection via the HTTP protocol.
 * 
 * Status: Minimal subset of functionality. Proxies only partially handled; Redirects not yet
 * handled. FileNameMap handling needs to be considered. useCaches, ifModifiedSince, and
 * allowUserInteraction need consideration as well as doInput and doOutput.
 * 
 * @author Aaron M. Renn <[e-mail]>
 * @author Warren Levy <[e-mail]>
 */
public final class Connection extends HttpURLConnection {
	/**
	 * The socket we are connected to
	 */
	private Socket socket;

	private static String proxyHost = null;
	private static int proxyPort = 80;
	private static boolean proxyInUse = false;

	static {
		// Recognize some networking properties listed at
		// http://java.sun.com/j2se/1.4/docs/guide/net/properties.html.
		String port = null;
		proxyHost = System.getProperty("http.proxyHost");

		if (proxyHost != null) {
			proxyInUse = true;

			if ((port = System.getProperty("http.proxyPort")) != null) {
				try {
					proxyPort = Integer.parseInt(port);
				} catch (Throwable t) {
					// Nothing.
				}
			}
		}
	}

	/**
	 * The InputStream for this connection.
	 */
	private DataInputStream inputStream;

	/**
	 * The OutputStream for this connection
	 */
	private OutputStream outputStream;

	/**
	 * bufferedOutputStream is a buffer to contain content of the HTTP request, and will be written
	 * to outputStream all at once
	 */
	private ByteArrayOutputStream bufferedOutputStream;

	/**
	 * The PrintWriter for this connection (used internally)
	 */
	private PrintWriter outputWriter;

	/**
	 * This is the object that holds the header field information
	 */
	private HeaderFieldHelper headers = new HeaderFieldHelper();

	/**
	 * Calls superclass constructor to initialize
	 */
	protected Connection(URL url) {
		super(url);

		/* Set up some variables */
		doInput = true;
		doOutput = true;
	}

	/**
	 * Connects to the remote host, sends the request, and parses the reply code and header
	 * information returned
	 */
	public void connect() throws IOException {
		// Call is ignored if already connected.
		if (connected)
			return;

		// Get address and port number.
		int port;

		if (proxyInUse) {
			port = proxyPort;
			socket = new Socket(proxyHost, port);
		} else {
			if ((port = url.getPort()) == -1)
				port = 80;

			// Open socket and output stream.
			socket = new Socket(url.getHost(), port);
		}

		if (doInput)
			inputStream = new DataInputStream(new BufferedInputStream(socket.getInputStream()));

		if (doOutput)
			outputStream = new BufferedOutputStream(socket.getOutputStream());

		bufferedOutputStream = new ByteArrayOutputStream(256); //default is too small
		outputWriter = new PrintWriter(new OutputStreamWriter(outputStream, "8859_1"));
		connected = true;

		sendRequest();
		receiveReply();
	}

	/**
	 * Disconnects from the remote server.
	 */
	public void disconnect() {
		if (socket != null) {
			try {
				socket.close();
			} catch (IOException e) {
				// Ignore errors in closing socket.
			}

			socket = null;
		}
	}

	/**
	 * Write HTTP request header and content to outputWriter.
	 */
	void sendRequest() throws IOException {
		// Send request including any request properties that were set.
		String file = url.getFile();
		if (file.length() == 0) {
			file = "/";
		}
		outputWriter.print(getRequestMethod() + " " + file + " HTTP/1.1\r\n");

		// Set additional HTTP headers.
		if (getRequestProperty("Host") == null) {
			setRequestProperty("Host", url.getHost());
		}

		if (getRequestProperty("Connection") == null) {
			setRequestProperty("Connection", "Close");
		}

		if (getRequestProperty("user-agent") == null) {
			setRequestProperty("user-agent", "gnu-classpath/" + System.getProperty("classpath.version"));
		}

		if (getRequestProperty("accept") == null) {
			setRequestProperty("accept", "*/*");
		}

		if (getRequestProperty("Content-type") == null) {
			setRequestProperty("Content-type", "application/x-www-form-urlencoded");
		}

		// Set correct content length.
		setRequestProperty("Content-length", String.valueOf(bufferedOutputStream.size()));

		// Write all req_props name-value pairs to the output writer.
		Iterator itr = getRequestProperties().entrySet().iterator();

		while (itr.hasNext()) {
			Map.Entry e = (Map.Entry) itr.next();
			outputWriter.print(e.getKey() + ": " + e.getValue() + "\r\n");
		}

		// One more CR-LF indicates end of header.
		outputWriter.print("\r\n");
		outputWriter.flush();

		// Write content
		bufferedOutputStream.writeTo(outputStream);
		outputStream.flush();
	}

	/**
	 * Read HTTP reply from inputStream.
	 */
	void receiveReply() throws IOException {
		// Parse the reply
		String line = inputStream.readLine();
		String saveline = line;
		int idx = line.indexOf(" ");

		if ((idx == -1) || (line.length() < (idx + 6)))
			throw new IOException("Server reply was unparseable: " + saveline);

		line = line.substring(idx + 1);
		String code = line.substring(0, 3);

		try {
			responseCode = Integer.parseInt(code);
		} catch (NumberFormatException e) {
			throw new IOException("Server reply was unparseable: " + saveline);
		}

		responseMessage = line.substring(4);

		// Now read the header lines
		String key = null, value = null;

		while (true) {
			line = inputStream.readLine();

			if (line.equals(""))
				break;

			// Check for folded lines
			if (line.startsWith(" ") || line.startsWith("\t")) {
				// Trim off leading space
				do {
					if (line.length() == 1)
						throw new IOException("Server header lines were unparseable: " + line);

					line = line.substring(1);
				} while (line.startsWith(" ") || line.startsWith("\t"));

				value = value + " " + line;
			} else {
				if (key != null) {
					headers.addHeaderField(key, value);
					key = null;
					value = null;
				}

				// Parse out key and value
				idx = line.indexOf(":");
				if ((idx == -1) || (line.length() < (idx + 2)))
					throw new IOException("Server header lines were unparseable: " + line);

				key = line.substring(0, idx);
				value = line.substring(idx + 1);

				// Trim off leading space
				while (value.startsWith(" ") || value.startsWith("\t")) {
					if (value.length() == 1)
						throw new IOException("Server header lines were unparseable: " + line);

					value = value.substring(1);
				}
			}
		}

		if (key != null) {
			headers.addHeaderField(key, value);
		}
	}

	/**
	 * Overrides java.net.HttpURLConnection.setRequestMethod() in order to restrict the available
	 * methods to only those we support.
	 * 
	 * @param method
	 *            The RequestMethod to use
	 * 
	 * @exception ProtocolException
	 *                If the specified method is not valid
	 */
	public void setRequestMethod(String method) throws ProtocolException {
		method = method.toUpperCase();

		if (method.equals("GET") || method.equals("HEAD") || method.equals("POST"))
			super.setRequestMethod(method);
		else
			throw new ProtocolException("Unsupported or unknown request method " + method);
	}

	/**
	 * Return a boolean indicating whether or not this connection is going through a proxy
	 * 
	 * @return true if using a proxy, false otherwise
	 */
	public boolean usingProxy() {
		return proxyInUse;
	}

	/**
	 * This method returns the header field key at the specified numeric index.
	 * 
	 * @param n
	 *            The index into the header field array
	 * 
	 * @return The name of the header field key, or <code>null</code> if the specified index is
	 *         not valid.
	 */
	public String getHeaderFieldKey(int n) {
		return headers.getHeaderFieldKeyByIndex(n);
	}

	/**
	 * This method returns the header field value at the specified numeric index.
	 * 
	 * @param n
	 *            The index into the header field array
	 * 
	 * @return The value of the specified header field, or <code>null</code> if the specified
	 *         index is not valid.
	 */
	public String getHeaderField(int n) {
		return headers.getHeaderFieldValueByIndex(n);
	}

	/**
	 * Returns an InputStream for reading from this connection. This stream will be "queued up" for
	 * reading just the contents of the requested file. Overrides URLConnection.getInputStream()
	 * 
	 * @return An InputStream for this connection.
	 * 
	 * @exception IOException
	 *                If an error occurs
	 */
	public InputStream getInputStream() throws IOException {
		if (inputStream != null)
			return inputStream;

		if (!connected)
			connect();

		return inputStream;
	}

	public OutputStream getOutputStream() throws IOException {
		if (!doOutput)
			throw new ProtocolException("Want output stream while haven't setDoOutput(true)");

		if (!method.equals("POST")) //But we might support "PUT" in future
			setRequestMethod("POST");

		if (!connected)
			connect();

		return bufferedOutputStream;
	}

} // class Connection