cms/corbaservices/MiniWebServer.java

//---PACKAGE DECLARATION---
package uk.org.iscream.corbaservices;

//---IMPORTS---
import java.net.*;
import java.io.*;
import java.util.*;

/**
 * MiniWebServer
 *
 * This provides a very basic webserver for serving IOR files.
 * This could easily serve other text files, but not binaries.
 *
 * @author  $Author: tdb1 $
 * @version $Id: MiniWebServer.java,v 1.4 2001/02/26 22:51:17 tdb1 Exp $
 */
public class MiniWebServer extends Thread {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public static final String REVISION = "$Revision: 1.4 $";
    
//---STATIC METHODS---

//---CONSTRUCTORS---
    
    /**
     * Construct a new MiniWebServer
     *
     * @param port The port to bind to
     * @param okUrlsConfig The URL list config file
     * @param webDir The web directory
     */
    public MiniWebServer(int port, String okUrlsConfig, String webDir) {
        _port = port;
        _okUrlsConfig = okUrlsConfig;
        _webDir = webDir;
    }

//---PUBLIC METHODS---

    /**
     * Main thread of execution. Keeps looping spawning off
     * Handler's to deal with each client. This should keep
     * going, and extra care has been taking with error
     * catching.
     */
    public void run() {
        // carry on forever
        while(true) {
            boolean run = true;
            ServerSocket serverSocket = null;
            try {
                serverSocket = new ServerSocket(_port);
            } catch (IOException e) {
                run = false;
                System.out.println(e);
                e.printStackTrace();
            }
            while(run) {
                try {
                    // get a new client and give it to a Handler
                    Socket socket = serverSocket.accept();
                    Handler handler = new Handler(socket);
                    handler.start();
                } catch (IOException e) {
                    run=false;
                    System.out.println(e);
                    e.printStackTrace();
                }
            }
        }
    }

//---PRIVATE METHODS---

    /**
     * Reads a file in given an URL. Very basic, and has only
     * been tested to work for URL's in the / directory.
     *
     * @param url The URL given to the webserver
     * @return A String containing data from the file
     */
    private String readUrl(String url) {
        // trim off the initial /
        if(url.startsWith("/")) {
            url = url.substring(1);
        }
        try {
            // need to prefix with web directory
            File file = new File(_webDir+"/"+url);
            if(file.exists() && file.canRead()) {
                // read in all the data
                String data = "";
                BufferedReader reader = new BufferedReader(new FileReader(file));
                while(reader.ready()) {
                    String line = reader.readLine();
                    if(line != null) {
                        data += line + "\n";
                    }
                }
                return data;
            }
            else {
                // return null if we can't read it
                return null;
            }
        } catch (IOException e) {
            System.out.println(e);
            e.printStackTrace();
            return null;
        }
    }
    
    /**
     * Checks if an URL is allowed. Failure of this method
     * indicates a client should be sent a 403.
     *
     * @param url the url to check
     * @return whether the url is permitted
     */
    private boolean okUrl(String url) {
        // recheck the list - this means the list can be
        // changed on the fly :)
        readOkUrls();
        Iterator i = _okUrls.iterator();
        while(i.hasNext()) {
            if(url.equals((String)i.next())) {
                // matched url against our list
                return true;
            }
        }
        return false;
    }
    
    /**
     * Reads the list of URLs into a list.
     */
    private void readOkUrls() {
        File file = new File(_okUrlsConfig);
        long lastMod = file.lastModified();
        // only want to re-read the list if it's changed
        if(lastMod > _okUrlsConfigStamp) {
            _okUrlsConfigStamp = lastMod;
            _okUrls = new LinkedList();
            if(file.exists() && file.canRead()) {
                try {
                    BufferedReader reader = new BufferedReader(new FileReader(file));
                    while(reader.ready()) {
                        String line = reader.readLine();
                        // ignore comments
                        if(!line.startsWith("#")) {
                            _okUrls.add(line);
                        }
                    }
                } catch(IOException e) {
                    System.out.println(e);
                    e.printStackTrace();
                }
            }
        }
    }
    
//---ACCESSOR/MUTATOR METHODS---

//---ATTRIBUTES---
    
    /**
     * The port we're bound to.
     */
    private int _port;
    
    /**
     * List of URLs that are permitted
     */
    private LinkedList _okUrls;
    
    /**
     * Config file for the URL list
     */
    private String _okUrlsConfig;
    
    /**
     * Timestamp of the URL config file
     */
    private long _okUrlsConfigStamp = 0;
    
    /**
     * Web directory
     */
    private String _webDir;

//---STATIC ATTRIBUTES---

//---INNER CLASSES---
    
    /**
     * A Handler to deal with each client. This is an inner
     * class because I felt like trying it out :)
     */
    private class Handler extends Thread {
        
        /**
         * Construct a new Handler
         *
         * @param socket The socket connected to the client
         */
        public Handler(Socket socket) {
            _socket = socket;
        }
        
        /**
         * Start the Handler running. This will read the URL
         * from the client, and respond accordinly.
         *
         * This does not try to deal with bad data
         */
        public void run() {
            BufferedReader reader = null;
            PrintWriter writer = null;
            try {
                // setup the reader and writer
                reader = new BufferedReader(new InputStreamReader(_socket.getInputStream()));
                writer = new PrintWriter(_socket.getOutputStream(), true);
                String line= "";
                String url = "";
                // keep reading from the client until it sends no more...
                do {
                    line = reader.readLine();
                    // ah, this contains the URL
                    if(line.startsWith("GET")) {
                        // strip off "GET "
                        url = line.substring(4);
                        // strip off anything past the URL
                        url = url.substring(0, url.lastIndexOf(' '));
                    }
                } while(!line.equals(""));
                // check the URL is allowed
                if(okUrl(url)) {
                    // read the file
                    String data = readUrl(url);
                    // check the file could be read, null means it couldn't
                    if(data != null) {
                        writer.println(data);
                    }
                    else {
                        // oh dear, couldn't find it, send a 404
                        writer.println("HTTP/1.1 404 Not Found\n");
                        writer.println("404 Not Found");
                    }
                }
                else {
                    // oh dear, not allowed, send a 403
                    writer.println("HTTP/1.1 403 Permission Denied\n");
                    writer.println("403 Permission Denied");
                }
            } catch(IOException e) {
                System.out.println(e);
                e.printStackTrace();
            }
            // clean up and close
            try {
                reader.close();
                writer.close();
                _socket.close();
            } catch(IOException e) {
                System.out.println(e);
                e.printStackTrace();
            }
        }
        
        /**
         * The socket connected to the client
         */
        private Socket _socket;
    }
    
}
Revision:	1.5
Committed:	Thu Mar 15 00:33:44 2001 UTC (23 years, 2 months ago) by tdb
Branch:	MAIN
CVS Tags:	PROJECT_COMPLETION
Changes since 1.4:	+3 -3 lines
Log Message:	Changed package structure from; uk.ac.ukc.iscream.corbaservices to; uk.org.iscream.corbaservices
#	User	Rev	Content
1	tdb	1.1	//---PACKAGE DECLARATION---
2	tdb	1.5	package uk.org.iscream.corbaservices;
3	tdb	1.1
4			//---IMPORTS---
5			import java.net.*;
6			import java.io.*;
7			import java.util.*;
8
9			/**
10			* MiniWebServer
11			*
12	tdb	1.3	* This provides a very basic webserver for serving IOR files.
13			* This could easily serve other text files, but not binaries.
14			*
15	tdb	1.2	* @author $Author: tdb1 $
16	tdb	1.5	* @version $Id: MiniWebServer.java,v 1.4 2001/02/26 22:51:17 tdb1 Exp $
17	tdb	1.1	*/
18			public class MiniWebServer extends Thread {
19
20			//---FINAL ATTRIBUTES---
21
22			/**
23			* The current CVS revision of this class
24			*/
25	tdb	1.5	public static final String REVISION = "$Revision: 1.4 $";
26	tdb	1.1
27			//---STATIC METHODS---
28
29			//---CONSTRUCTORS---
30	tdb	1.3
31			/**
32			* Construct a new MiniWebServer
33			*
34			* @param port The port to bind to
35			* @param okUrlsConfig The URL list config file
36			* @param webDir The web directory
37			*/
38	tdb	1.2	public MiniWebServer(int port, String okUrlsConfig, String webDir) {
39	tdb	1.1	_port = port;
40			_okUrlsConfig = okUrlsConfig;
41	tdb	1.2	_webDir = webDir;
42	tdb	1.1	}
43
44			//---PUBLIC METHODS---
45
46	tdb	1.3	/**
47			* Main thread of execution. Keeps looping spawning off
48			* Handler's to deal with each client. This should keep
49			* going, and extra care has been taking with error
50			* catching.
51			*/
52	tdb	1.1	public void run() {
53			// carry on forever
54			while(true) {
55			boolean run = true;
56			ServerSocket serverSocket = null;
57			try {
58			serverSocket = new ServerSocket(_port);
59			} catch (IOException e) {
60			run = false;
61			System.out.println(e);
62			e.printStackTrace();
63			}
64			while(run) {
65			try {
66	tdb	1.3	// get a new client and give it to a Handler
67	tdb	1.1	Socket socket = serverSocket.accept();
68			Handler handler = new Handler(socket);
69			handler.start();
70			} catch (IOException e) {
71			run=false;
72			System.out.println(e);
73			e.printStackTrace();
74			}
75			}
76			}
77			}
78
79			//---PRIVATE METHODS---
80
81	tdb	1.3	/**
82			* Reads a file in given an URL. Very basic, and has only
83			* been tested to work for URL's in the / directory.
84			*
85			* @param url The URL given to the webserver
86			* @return A String containing data from the file
87			*/
88	tdb	1.1	private String readUrl(String url) {
89	tdb	1.3	// trim off the initial /
90	tdb	1.1	if(url.startsWith("/")) {
91			url = url.substring(1);
92			}
93			try {
94	tdb	1.3	// need to prefix with web directory
95	tdb	1.2	File file = new File(_webDir+"/"+url);
96	tdb	1.1	if(file.exists() && file.canRead()) {
97	tdb	1.3	// read in all the data
98	tdb	1.1	String data = "";
99			BufferedReader reader = new BufferedReader(new FileReader(file));
100			while(reader.ready()) {
101	tdb	1.4	String line = reader.readLine();
102			if(line != null) {
103			data += line + "\n";
104			}
105	tdb	1.1	}
106			return data;
107			}
108			else {
109	tdb	1.3	// return null if we can't read it
110	tdb	1.1	return null;
111			}
112			} catch (IOException e) {
113			System.out.println(e);
114			e.printStackTrace();
115			return null;
116			}
117			}
118	tdb	1.3
119			/**
120			* Checks if an URL is allowed. Failure of this method
121			* indicates a client should be sent a 403.
122			*
123			* @param url the url to check
124			* @return whether the url is permitted
125			*/
126	tdb	1.1	private boolean okUrl(String url) {
127	tdb	1.3	// recheck the list - this means the list can be
128			// changed on the fly :)
129	tdb	1.1	readOkUrls();
130			Iterator i = _okUrls.iterator();
131			while(i.hasNext()) {
132			if(url.equals((String)i.next())) {
133	tdb	1.3	// matched url against our list
134	tdb	1.1	return true;
135			}
136			}
137			return false;
138			}
139
140	tdb	1.3	/**
141			* Reads the list of URLs into a list.
142			*/
143	tdb	1.1	private void readOkUrls() {
144			File file = new File(_okUrlsConfig);
145			long lastMod = file.lastModified();
146	tdb	1.3	// only want to re-read the list if it's changed
147	tdb	1.1	if(lastMod > _okUrlsConfigStamp) {
148			_okUrlsConfigStamp = lastMod;
149			_okUrls = new LinkedList();
150			if(file.exists() && file.canRead()) {
151			try {
152			BufferedReader reader = new BufferedReader(new FileReader(file));
153			while(reader.ready()) {
154			String line = reader.readLine();
155	tdb	1.3	// ignore comments
156	tdb	1.1	if(!line.startsWith("#")) {
157			_okUrls.add(line);
158			}
159			}
160			} catch(IOException e) {
161			System.out.println(e);
162			e.printStackTrace();
163			}
164			}
165			}
166			}
167
168			//---ACCESSOR/MUTATOR METHODS---
169
170			//---ATTRIBUTES---
171	tdb	1.3
172			/**
173			* The port we're bound to.
174			*/
175	tdb	1.1	private int _port;
176	tdb	1.3
177			/**
178			* List of URLs that are permitted
179			*/
180	tdb	1.1	private LinkedList _okUrls;
181	tdb	1.3
182			/**
183			* Config file for the URL list
184			*/
185	tdb	1.1	private String _okUrlsConfig;
186	tdb	1.3
187			/**
188			* Timestamp of the URL config file
189			*/
190	tdb	1.1	private long _okUrlsConfigStamp = 0;
191	tdb	1.3
192			/**
193			* Web directory
194			*/
195	tdb	1.2	private String _webDir;
196	tdb	1.1
197			//---STATIC ATTRIBUTES---
198
199			//---INNER CLASSES---
200	tdb	1.3
201			/**
202			* A Handler to deal with each client. This is an inner
203			* class because I felt like trying it out :)
204			*/
205	tdb	1.1	private class Handler extends Thread {
206	tdb	1.3
207			/**
208			* Construct a new Handler
209			*
210			* @param socket The socket connected to the client
211			*/
212	tdb	1.1	public Handler(Socket socket) {
213			_socket = socket;
214			}
215	tdb	1.3
216			/**
217			* Start the Handler running. This will read the URL
218			* from the client, and respond accordinly.
219			*
220			* This does not try to deal with bad data
221			*/
222	tdb	1.1	public void run() {
223			BufferedReader reader = null;
224			PrintWriter writer = null;
225			try {
226	tdb	1.3	// setup the reader and writer
227	tdb	1.1	reader = new BufferedReader(new InputStreamReader(_socket.getInputStream()));
228			writer = new PrintWriter(_socket.getOutputStream(), true);
229			String line= "";
230			String url = "";
231	tdb	1.3	// keep reading from the client until it sends no more...
232	tdb	1.1	do {
233			line = reader.readLine();
234	tdb	1.3	// ah, this contains the URL
235	tdb	1.1	if(line.startsWith("GET")) {
236	tdb	1.3	// strip off "GET "
237	tdb	1.1	url = line.substring(4);
238	tdb	1.3	// strip off anything past the URL
239	tdb	1.1	url = url.substring(0, url.lastIndexOf(' '));
240			}
241			} while(!line.equals(""));
242	tdb	1.3	// check the URL is allowed
243	tdb	1.1	if(okUrl(url)) {
244	tdb	1.3	// read the file
245	tdb	1.1	String data = readUrl(url);
246	tdb	1.3	// check the file could be read, null means it couldn't
247	tdb	1.1	if(data != null) {
248			writer.println(data);
249			}
250			else {
251	tdb	1.3	// oh dear, couldn't find it, send a 404
252	tdb	1.1	writer.println("HTTP/1.1 404 Not Found\n");
253			writer.println("404 Not Found");
254			}
255			}
256			else {
257	tdb	1.3	// oh dear, not allowed, send a 403
258	tdb	1.1	writer.println("HTTP/1.1 403 Permission Denied\n");
259			writer.println("403 Permission Denied");
260			}
261			} catch(IOException e) {
262			System.out.println(e);
263			e.printStackTrace();
264			}
265	tdb	1.3	// clean up and close
266	tdb	1.1	try {
267			reader.close();
268			writer.close();
269			_socket.close();
270			} catch(IOException e) {
271			System.out.println(e);
272			e.printStackTrace();
273			}
274			}
275	tdb	1.3
276			/**
277			* The socket connected to the client
278			*/
279	tdb	1.1	private Socket _socket;
280			}
281
282			}