http.java

How to get the java home dir.

// Originally based on work by Jonathan Revusky

// To encode strings use java.net.URLEncoder.encode;
// and Java.net.URLDecoder.decode or Request.
/*
 * copyright (c) 1998-2008 Canadian Mind Products
 * Roedy Green
 * Canadian Mind Products
 * #327 - 964 Heywood Avenue
 * Victoria, BC Canada V8V 2Y5
 * tel: [phone]
 * roedy g at mindprod dotcom
 * http://mindprod.com
 * 1.1 2007-07-19 improved handling of responseCode
 * 1.2 2007-07-27 use UTF-8 instead of 8859_1.
 * 1.3 2007-08-24 readStringBlocking, readBytesBlocking, encoding on Get
 * 1.4 2007-09-26 add TIMEOUT
 * 1.5 2007-12-30 add alternate get and post methods that take a full URL.
 * 1.6 2008-01-14 add gzip option on read
 * 1.7 2008-07-25 add configurable User-Agent, add Base Http class.
 * 1.8 2008-07-27 handle case where URL given was not HTTP
 * 1.9 2008-08-22 support accept-charset, accept-encoding and accept-language.  Fix bugs in gzip support.
 */
package com.mindprod.http;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URLConnection;

/**
 * base class to Post, Get, Probe
 *
 * @author Roedy Green, Canadian Mind Products may be copied and used freely for any purpose but military.
 * @version 1.9 2008-08-22 support accept-charset, accept-encoding and accept-language.  Fix bugs in gzip support.
 */
abstract class Http
    {
    // ------------------------------ FIELDS ------------------------------

    /**
     * true if want extra debugging ouput
     */
    static final boolean DEBUGGING = false;

    /**
     * responseCode to give if is no proper one
     */
    static final int DEFAULT_RESPONSE_CODE = -1;
    /**
     * responseMessage to give if is no proper one. Might mean tried to use http: on https: URL.
     */
    static final String DEFAULT_RESPONSE_MESSAGE = "no connect";

    /**
     * the referer we pretend to be.
     * By default null, for none.
     */

    String referer = null;
    /**
     * responseCode in words from most recent post
     */
    String responseMessage;

    /**
     * the browser we pretend to be
     */
    String userAgent = "Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1";

    /**
     * Allow 50 seconds to connect
     */
    int connectTimeout = 50 * 1000;

    /**
     * Allow 40 seconds for a read to go without progress
     */
    int readTimeout = 40 * 1000;
    /**
     * responseCode from most recent post
     */
    int responseCode;

    // -------------------------- PUBLIC INSTANCE  METHODS --------------------------
    /**
     * responseCode from most recent post/get
     *
     * @return responseCode
     */
    public int getResponseCode()
        {
        return responseCode;
        }

    /**
     * responseCode from most recent post/get
     *
     * @return responseCode
     */
    public String getResponseMessage()
        {
        return responseMessage;
        }

    /**
     * override the default connect timeout of 50 seconds
     *
     * @param connectTimeout timeout to connect in ms. Note int not long.
     */
    public void setConnectTimeout( int connectTimeout )
        {
        this.connectTimeout = connectTimeout;
        }

    /**
     * override the default read timeout of 40 seconds
     *
     * @param readTimeout timeout to connect int ms. Note int not long.
     */
    public void setReadTimeout( int readTimeout )
        {
        this.readTimeout = readTimeout;
        }

    /**
     * set  theRefer ie. the name of a web page this request ostensibly came from.
     *
     * @param referer e.g "http://mindprod.com/index.html", null for none.
     * @see <a href="http://mindprod.com/jgloss/http.html">details on Referer</a>
     */
    public void setReferer( String referer )
        {
        this.referer = referer;
        }

    /**
     * override the default User-Agent
     *
     * @param userAgent User-Agent string a browser uses in an HTTP header to identify itself.
     *                  null for no User Agent.  By default you get Firefox.
     * @see <a href="http://mindprod.com/jgloss/http.html">details on User-Agent</a>
     */
    public void setUserAgent( String userAgent )
        {
        this.userAgent = userAgent;
        }

    // --------------------------- CONSTRUCTORS ---------------------------

    /**
     * no public instantiation.  Just a base class.
     */
    Http()
        {
        }

    // -------------------------- OTHER METHODS --------------------------

    /**
     * process the response from the request we sent the server
     *
     * @param encoding Encoding to use to interpret the result.
     * @param urlc     the HttpURLConnection, all ready to go but for the connect.
     * @return content of the response, decompressed, decoded.
     * @throws java.io.IOException if trouble reading the stream.
     */
    String processResponse( String encoding, HttpURLConnection urlc )
            throws IOException
        {
        urlc.connect();
        /* save responseCode for later retrieval */
        responseCode = urlc.getResponseCode();
        responseMessage = urlc.getResponseMessage();

        // get size of message. -1 means comes in an indeterminate number of chunks.
        int estimatedLength = urlc.getContentLength();
        if ( estimatedLength < 0 )
            {
            // quite common for no length field
            estimatedLength = 32 * 1024;
            }
        // InputStream gives us the raw bytes. We must decompress and decode the 8-bit chars..
        // actually a sun.net.www.protocol.http.HttpURLConnection.HttpInputStream
        final InputStream is = urlc.getInputStream();

        final String contentType = urlc.getContentType();
        //  Content-Type: text/html; charset=utf-8
        int place = contentType.lastIndexOf( "charset=" );
        final String revisedEncoding;
        if ( place >= 0 )
            {
            revisedEncoding = contentType.substring( place + "charset=".length() ).trim().toUpperCase();
            }
        else
            {
            revisedEncoding = encoding;
            }

        // content encoding might be null. We don't handle deflate or Unix compress.
        final boolean gzipped = "gzip".equals( urlc.getContentEncoding() )
                                || "x-gzip".equals( urlc.getContentEncoding() );
        // R E A D
        String result = Read.readStringBlocking( is,
                estimatedLength,
                readTimeout,
                gzipped,
                revisedEncoding );

        if ( DEBUGGING )
            {
            System.out.println( "--------------------------------" );
            System.out.println( "ResponseCode:" + responseCode );
            System.out.println( "ResponseMessage:" + responseMessage );
            System.out.println( "ContentType:" + contentType );
            System.out.println( "CharSet:" + revisedEncoding );
            System.out.println( "ContentEncoding:" + urlc.getContentEncoding() );
            System.out.println( "Result:" + ( result == null ? "null" : result.substring( 0, Math.min( result.length(), 300 ) ) ) );
            }
        // C L O S E
        is.close();
        urlc.disconnect();
        return result;
        }

    /**
     * set up the standard properties on the connection
     *
     * @param urlc Connection we are setting up.
     */
    protected void setStandardProperties( URLConnection urlc )
        {
        urlc.setConnectTimeout( connectTimeout );
        urlc.setReadTimeout( readTimeout );

        if ( userAgent != null )
            {
            urlc.setRequestProperty( "user-agent", userAgent );
            }
        if ( referer != null )
            {
            urlc.setRequestProperty( "referer", referer );
            }
        urlc.setRequestProperty( "accept",
                "text/html, image/png, image/jpeg, image/gif, application/x-java-serialized-object, text/x-java-source, text/xml, application/xml, "
                +
                "text/css, application/x-java-jnlp-file, text/plain, application/zip, application/octet-stream, *; q=.2, */*; q=.2" );
        urlc.setRequestProperty( "accept-charset", "iso-8859-1, utf-8, utf-16, *;q=0.1" );
        // no deflate.
        urlc.setRequestProperty( "accept-encoding", "gzip, x-gzip, identity, *;q=0" );
        // relaxed, prefer English
        urlc.setRequestProperty( "accept-language", "en-CA,en;q=0.9" );
        }
    }