SimpleSocket.java

   1 package be.nikiroo.jvcard.remote;
   2
   3 import java.io.BufferedReader;
   4 import java.io.IOException;
   5 import java.io.InputStreamReader;
   6 import java.io.PrintWriter;
   7 import java.net.InetAddress;
   8 import java.net.Socket;
   9 import java.util.Arrays;
  10 import java.util.LinkedList;
  11 import java.util.List;
  12
  13 /**
  14  * A client or server connection, that will allow you to connect to, send and
  15  * receive data to/from a jVCard remote server.
  16  *
  17  *
  18  *
  19  * @author niki
  20  */
  21 public class SimpleSocket {
  22         /**
  23          * The current version of the network protocol.
  24          */
  25         static public final int CURRENT_VERSION = 1;
  26
  27         /**
  28          * The end of block marker.
  29          *
  30          * An end of block marker needs to be on a line on itself to be valid, and
  31          * will denote the end of a block of data.
  32          */
  33         static private String EOB = ".";
  34
  35         private Socket s;
  36         private PrintWriter out;
  37         private BufferedReader in;
  38         private int version; // version of the OTHER end, not this one (this one is
  39                                                         // CURRENT_VERSION obviously)
  40
  41         private String label; // can be used for debugging
  42
  43         /**
  44          * Create a new {@link SimpleSocket} with the given {@link Socket}.
  45          *
  46          * @param s
  47          *            the {@link Socket}
  48          */
  49         public SimpleSocket(Socket s, String label) {
  50                 this.s = s;
  51                 this.label = label;
  52         }
  53
  54         /**
  55          * Return the label of this {@link SimpleSocket}. This is mainly used for
  56          * debugging purposes or user display if any. It is optional.
  57          *
  58          * @return the label
  59          */
  60         public String getLabel() {
  61                 if (label == null)
  62                         return "[no name]";
  63                 return label;
  64         }
  65
  66         /**
  67          * Open the {@link SimpleSocket} for reading/writing and negotiates the
  68          * version.
  69          *
  70          * Note that you <b>MUST</b> call {@link SimpleSocket#close()} when you are
  71          * done to release the acquired resources.
  72          *
  73          * @param client
  74          *            TRUE for clients, FALSE for servers (server speaks first)
  75          *
  76          * @throws IOException
  77          *             in case of IO error
  78          */
  79         public void open(boolean client) throws IOException {
  80                 out = new PrintWriter(s.getOutputStream(), false);
  81                 in = new BufferedReader(new InputStreamReader(s.getInputStream()));
  82
  83                 if (client) {
  84                         version = new CommandInstance(receiveLine(), -1).getVersion();
  85                         sendLine(new CommandInstance(Command.VERSION, CURRENT_VERSION)
  86                                         .toString());
  87                 } else {
  88                         send(new CommandInstance(Command.VERSION, CURRENT_VERSION)
  89                                         .toString());
  90                         // TODO: i18n
  91                         send("[Some help info here]");
  92                         send("you need to reply with your VERSION + end of block");
  93                         send("please send HELP in a full block or help");
  94                         sendBlock();
  95                         version = new CommandInstance(receiveLine(), -1).getVersion();
  96                 }
  97         }
  98
  99         /**
 100          * Close the connection and release acquired resources.
 101          *
 102          * @return TRUE if everything was closed properly, FALSE if the connection
 103          *         was broken (in all cases, resources are released)
 104          */
 105         public boolean close() {
 106                 boolean broken = false;
 107
 108                 try {
 109                         sendBlock();
 110                         broken = out.checkError();
 111                 } catch (IOException e) {
 112                         broken = true;
 113                 }
 114
 115                 try {
 116                         s.close();
 117                 } catch (IOException e) {
 118                         e.printStackTrace();
 119                         broken = true;
 120                         try {
 121                                 in.close();
 122                         } catch (IOException ee) {
 123                         }
 124                         out.close();
 125                 }
 126
 127                 s = null;
 128                 in = null;
 129                 out = null;
 130
 131                 return !broken;
 132         }
 133
 134         /**
 135          * Sends lines to the remote server. Do <b>NOT</b> sends the end-of-block
 136          * marker.
 137          *
 138          * @param data
 139          *            the data to send
 140          *
 141          * @throws IOException
 142          *             in case of IO error
 143          */
 144         protected void send(String data) throws IOException {
 145                 if (data != null) {
 146                         out.write(data);
 147                 }
 148
 149                 out.write("\n");
 150
 151                 if (out.checkError())
 152                         throw new IOException();
 153         }
 154
 155         /**
 156          * Sends an end-of-block marker to the remote server.
 157          *
 158          * @throws IOException
 159          *             in case of IO error
 160          */
 161         public void sendBlock() throws IOException {
 162                 sendBlock((List<String>) null);
 163         }
 164
 165         /**
 166          * Sends commands to the remote server, then sends an end-of-block marker.
 167          *
 168          * @param data
 169          *            the data to send
 170          *
 171          * @throws IOException
 172          *             in case of IO error
 173          */
 174         public void sendLine(String data) throws IOException {
 175                 sendBlock(Arrays.asList(new String[] { data }));
 176         }
 177
 178         /**
 179          * Sends commands to the remote server, then sends an end-of-block marker.
 180          *
 181          * @param data
 182          *            the data to send
 183          *
 184          * @throws IOException
 185          *             in case of IO error
 186          */
 187         public void sendBlock(List<String> data) throws IOException {
 188                 if (data != null) {
 189                         for (String dataLine : data) {
 190                                 send(dataLine);
 191                         }
 192                 }
 193
 194                 send(EOB);
 195         }
 196
 197         /**
 198          * Sends commands to the remote server, then sends an end-of-block marker.
 199          *
 200          * @param command
 201          *            the {@link Command} to send
 202          *
 203          * @throws IOException
 204          *             in case of IO error
 205          */
 206         public void sendCommand(Command command) throws IOException {
 207                 sendCommand(command, null);
 208         }
 209
 210         /**
 211          * Sends commands to the remote server, then sends an end-of-block marker.
 212          *
 213          * @param command
 214          *            the data to send
 215          *
 216          * @param param
 217          *            the parameter for this command if any
 218          *
 219          * @throws IOException
 220          *             in case of IO error
 221          */
 222         public void sendCommand(Command command, String param) throws IOException {
 223                 sendLine(new CommandInstance(command, param, CURRENT_VERSION).toString());
 224         }
 225
 226         /**
 227          * Read a line from the remote server.
 228          *
 229          * Do <b>NOT</b> read until the end-of-block marker, and can return said
 230          * block without conversion.
 231          *
 232          * @return the read line
 233          *
 234          * @throws IOException
 235          *             in case of IO error
 236          */
 237         protected String receive() throws IOException {
 238                 String line = in.readLine();
 239                 return line;
 240         }
 241
 242         /**
 243          * Read lines from the remote server until the end-of-block ("\0\n") marker
 244          * is detected.
 245          *
 246          * @return the read lines without the end marker, or NULL if nothing more to
 247          *         read
 248          *
 249          * @throws IOException
 250          *             in case of IO error
 251          */
 252         public List<String> receiveBlock() throws IOException {
 253                 List<String> result = new LinkedList<String>();
 254
 255                 String line = receive();
 256                 for (; line != null && !line.equals(EOB); line = receive()) {
 257                         result.add(line);
 258                 }
 259
 260                 if (line == null)
 261                         return null;
 262
 263                 return result;
 264         }
 265
 266         /**
 267          * Read a line from the remote server then read until the next end-of-block
 268          * marker.
 269          *
 270          * @return the parsed line, or NULL if nothing more to read
 271          *
 272          * @throws IOException
 273          *             in case of IO error
 274          */
 275         public String receiveLine() throws IOException {
 276                 List<String> lines = receiveBlock();
 277
 278                 if (lines.size() > 0)
 279                         return lines.get(0);
 280
 281                 return null;
 282         }
 283
 284         /**
 285          * Read a line from the remote server and convert it to a
 286          * {@link CommandInstance}, then read until the next end-of-block marker.
 287          *
 288          * @return the parsed {@link CommandInstance}
 289          *
 290          * @throws IOException
 291          *             in case of IO error
 292          */
 293         public CommandInstance receiveCommand() throws IOException {
 294                 String line = receive();
 295                 CommandInstance cmd = new CommandInstance(line, version);
 296                 receiveBlock();
 297                 return cmd;
 298         }
 299
 300         @Override
 301         public String toString() {
 302                 String source = "[not connected]";
 303                 InetAddress iadr = s.getInetAddress();
 304                 if (iadr != null)
 305                         source = iadr.getHostName();
 306
 307                 return getLabel() + " (" + source + ")";
 308         }
 309 }