File-Download/WebServer.java at master · dhruvishah2312/File-Download · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
/*
 *
 *  Name:-Dhruvi Shah
 *  10015504023
 * Project - 1
 * -----------------------------------------------------
 * The program is a client server application that allows the user to download a file from the server.
 *
 * Steps to run the Server on command line:-
 * 1. Open Command Prompt.
 * 2. Open the directory where the project is stored.
 * 3. Compile the code using "javac WebServer.java"
 * 4. Execute the following command "java WebServer 6789"
 * 5. The program execution will start and the server will wait for a client to connect to.
 *
 * Reference:
 * - Programming Assignment - 1 (Document provided on Blackboard)
 * - http://www.codejava.net/java-se/networking/use-httpurlconnection-to-download-file-from-an-http-url
 *
 */
import java.io.* ;
import java.net.* ;
import java.util.* ;
public final class WebServer {

private static ServerSocket serverSocket;
public static Socket clientSocket;
public static void main(String args[]) throws Exception {
		int portNo = Integer.parseInt(args[0]);

		//Set the port number
		serverSocket = new ServerSocket(portNo);
		serverSocket.setSoTimeout(200000);

		while(true) {


			try {
				//Establish a connection
				System.out.println("Waiting for client on port " + serverSocket.getLocalPort() + "...");
				clientSocket = serverSocket.accept();

				//Produce HTTP service request and listen for a TCP connection
				HttpRequest request = new HttpRequest(clientSocket);
				Thread thread = new Thread (request);
				thread.start();
			} catch (Exception e) { //to catch the timeout exception
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}

	}
}
final class HttpRequest implements Runnable
{

	final static String CRLF = "\r\n";
	Socket socket;

	public HttpRequest(Socket socket) throws Exception {
		 this.socket = socket;
	}

	@Override
	public void run() {
		try {
			requestProcess();
		} catch (Exception e) {
			System.out.println(e);
		}
	}

	private void requestProcess() throws Exception {

		//Get a reference to the socket's input and output streams
		DataOutputStream out = new DataOutputStream(socket.getOutputStream());
		BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));

		//Get the request line of the HTTP message
		String request = br.readLine();

		System.out.println("Request: " + request);


		System.out.println("Client address: " + socket.getInetAddress());
		System.out.println("Client port: " + socket.getPort());
		System.out.println("Peer address of server: " + socket.getInetAddress() + " " + socket.getLocalPort());
		System.out.println("Peer address of client: " + socket.getInetAddress() + " " + socket.getPort());

		//Get and display the header lines
		String header = null;
		while ((header = br.readLine()).length() != 0) {
			System.out.println("HeaderLine: "+ header);
		}

		//Extract the filename from the request line.
		StringTokenizer tokens = new StringTokenizer(request);
		System.out.println("Token" + tokens);
		tokens.nextToken();
		String fileName = "." + tokens.nextToken();
		System.out.println("\nTokens:" + fileName);

		FileInputStream fis = null;
		boolean fileExists = true;

		//Open the requested file if it exists
		try {
				fis = new FileInputStream(fileName);
		} catch (FileNotFoundException e) {
			fileExists = false;

		}

		//Construct the response message
		String statusLine = null;
		String contentTypeLine = null;
		String entityBody = null;

		if(fileExists) {
			statusLine = "HTTP/1.1 200 OK";
			contentTypeLine = "\nContent-Type: " + contentType(fileName) + CRLF;
		} else {
			statusLine = "HTTP/1.1 404 Not Found";
			contentTypeLine = " ";
			entityBody = "HTML>" + "<HEAD><TITLE>Not Found</TITLE></HEAD>" + "<BODY>Not Found</BODY></HTML";
		}

		out.writeBytes(statusLine);
		out.writeBytes(contentTypeLine);
		out.writeBytes(CRLF);

		if (fileExists) {
			sendBytes(fis, out);
			fis.close();
		} else {
			out.writeBytes(entityBody);
		}

		out.close();
		br.close();
		socket.close();
	}

	private static void sendBytes(FileInputStream fis, OutputStream os) throws Exception {

		//Construct a buffer
		byte[] buffer = new byte[1024];
		int bytes = 0;

		//Copy the requested file into the output stream
		while((bytes = fis.read(buffer)) != -1 ) {
			os.write(buffer, 0, bytes);
		}
	}

	private static String contentType(String fileName) {
		if(fileName.endsWith(".htm") || fileName.endsWith(".html")) {
			return "text/html";
		}
		if(fileName.endsWith(".jpeg")) {
			return "image/jpeg";
		}
		if(fileName.endsWith(".gif")) {
			return "image/gif";
		}
		return "application/octet-stream";
	}
}