ftpconnection.java

一个利用Java语言实现的ftp程序

         // reset state variables
         resetState();
         
         // argument check
         if(!request.hasArgument()) {
            out.write(mFtpStatus.getResponse(501, request, mUser, null));
            return;  
         }
        
         // get filenames
         String fileName = request.getArgument();
         fileName = mUser.getVirtualDirectory().getAbsoluteName(fileName);
         String physicalName = mUser.getVirtualDirectory().getPhysicalName(fileName);
         File reqFile = new File(physicalName);
         
         // print file size
         if(reqFile.exists()) {
             String args[] = {String.valueOf(reqFile.length())};             
             out.write(mFtpStatus.getResponse(213, request, mUser, args));
         }
         else {
             out.write(mFtpStatus.getResponse(550, request, mUser, null));
         }
     } 
     
     
     /**
      * <code>STAT [&lt;SP&gt; &lt;pathname&gt;] &lt;CRLF&gt;</code><br>
      *
      * This command shall cause a status response to be sent over
      * the control connection in the form of a reply.
      */
     public void doSTAT(FtpRequest request, FtpWriter out) throws IOException {
         
         // reset state variables
         resetState();
        
         // write the status info
         String args[] = {
            mConfig.getSelfAddress().getHostAddress(),
            mControlSocket.getInetAddress().getHostAddress(),
            mUser.getName()
         };
         out.write(mFtpStatus.getResponse(211, request, mUser, args)); 
     } 
     
     
     /**
      * <code>STOR &lt;SP&gt; &lt;pathname&gt; &lt;CRLF&gt;</code><br>
      *
      * This command causes the server-DTP to accept the data
      * transferred via the data connection and to store the data as
      * a file at the server site.  If the file specified in the
      * pathname exists at the server site, then its contents shall
      * be replaced by the data being transferred.  A new file is
      * created at the server site if the file specified in the
      * pathname does not already exist.
      */
     public void doSTOR(FtpRequest request, FtpWriter out) throws IOException {

         InputStream is = null;
         OutputStream os = null;
         try {

             // set state variables
             long skipLen = (mbReset) ? mlSkipLen : 0;
             resetState();
             
             // argument check
             if(!request.hasArgument()) {
                out.write(mFtpStatus.getResponse(501, request, mUser, null));
                return;  
             }
             
             // get filenames
             String fileName = request.getArgument();
             fileName = mUser.getVirtualDirectory().getAbsoluteName(fileName);
             String physicalName = mUser.getVirtualDirectory().getPhysicalName(fileName);
             File requestedFile = new File(physicalName);
             
             // get permission
             if(!mUser.getVirtualDirectory().hasCreatePermission(physicalName, true)) {
                 out.write(mFtpStatus.getResponse(550, request, mUser, null));
                 return;
             }
             
             // now transfer file data
             out.write(mFtpStatus.getResponse(150, request, mUser, null));
             
             // get data connection
             Socket dataSoc = mDataConnection.getDataSocket();
             if (dataSoc == null) {
                  out.write(mFtpStatus.getResponse(550, request, mUser, null));
                  return;
             }
             is = dataSoc.getInputStream();
             
             // go to the appropriate offset
             RandomAccessFile raf = new RandomAccessFile(requestedFile, "rw");
             raf.setLength(skipLen);
             raf.seek(skipLen);
             os = mUser.getOutputStream( new FileOutputStream(raf.getFD()) );
             
             // get data from client
             StreamConnector msc = new StreamConnector(is, os);
             msc.setMaxTransferRate(mUser.getMaxUploadRate());
             msc.setObserver(this);
             msc.connect();
             if(msc.hasException()) {
                 out.write(mFtpStatus.getResponse(451, request, mUser, null));
                 return;
             }
             else {
                 mConfig.getStatistics().setUpload(requestedFile, mUser, msc.getTransferredSize());
             }
             
             out.write(mFtpStatus.getResponse(226, request, mUser, null));
         }
         catch(IOException ex) {
             out.write(mFtpStatus.getResponse(425, request, mUser, null));
         }
         finally {
             IoUtils.close(is);
             IoUtils.close(os);
             mDataConnection.closeDataSocket();
         }
     }
     
     
     /**
      * <code>STOU &lt;CRLF&gt;</code><br>
      *
      * This command behaves like STOR except that the resultant
      * file is to be created in the current directory under a name
      * unique to that directory.  The 250 Transfer Started response
      * must include the name generated.
      */
     public void doSTOU(FtpRequest request, FtpWriter out) throws IOException {

         InputStream is = null;
         OutputStream os = null;
         try {
         
             // reset state variables
             resetState();
             
             // get filenames
             String fileName = mUser.getVirtualDirectory().getAbsoluteName("ftp.dat");
             String physicalName = mUser.getVirtualDirectory().getPhysicalName(fileName);
             File requestedFile = new File(physicalName);
             requestedFile = IoUtils.getUniqueFile(requestedFile);
             fileName = mUser.getVirtualDirectory().getVirtualName(requestedFile.getAbsolutePath());
             String args[] = {fileName};
             
             // check permission
             if(!mUser.getVirtualDirectory().hasCreatePermission(fileName, false)) {
                 out.write(mFtpStatus.getResponse(550, request, mUser, null));
                 return;
             }
             
             // now transfer file data
             out.write(mFtpStatus.getResponse(150, request, mUser, null));
             Socket dataSoc = mDataConnection.getDataSocket();
             if (dataSoc == null) {
                  out.write(mFtpStatus.getResponse(550, request, mUser, args));
                  return;
             }
             
             // receive data from client
             is = dataSoc.getInputStream();
             os = mUser.getOutputStream( new FileOutputStream(requestedFile) );
             
             StreamConnector msc = new StreamConnector(is, os);
             msc.setMaxTransferRate(mUser.getMaxUploadRate());
             msc.setObserver(this);
             msc.connect();
             if(msc.hasException()) {
                 out.write(mFtpStatus.getResponse(451, request, mUser, null));
                 return;
             }
             else {
                 mConfig.getStatistics().setUpload(requestedFile, mUser, msc.getTransferredSize());
             }
             
             out.write(mFtpStatus.getResponse(226, request, mUser, null));
             mDataConnection.closeDataSocket();
             out.write(mFtpStatus.getResponse(250, request, mUser, args));
         }
         catch(IOException ex) {
             out.write(mFtpStatus.getResponse(425, request, mUser, null));
         }
         finally {
            IoUtils.close(is);
            IoUtils.close(os);
            mDataConnection.closeDataSocket(); 
         }
     }
     
     
     /**
      * <code>STRU &lt;SP&gt; &lt;structure-code&gt; &lt;CRLF&gt;</code><br>
      *
      * The argument is a single Telnet character code specifying
      * file structure.
      */
     public void doSTRU(FtpRequest request, FtpWriter out) throws IOException {
         
         // reset state variables
         resetState();
         
         // argument check
         if(!request.hasArgument()) {
            out.write(mFtpStatus.getResponse(501, request, mUser, null));
            return;  
         }
         
         // set structure
         if (mUser.setStructure(request.getArgument().charAt(0))) {
            out.write(mFtpStatus.getResponse(200, request, mUser, null));
         }
         else {
             out.write(mFtpStatus.getResponse(504, request, mUser, null));
         }
     }
     
     
     /**
      * <code>SYST &lt;CRLF&gt;</code><br> 
      *
      * This command is used to find out the type of operating
      * system at the server.
      */
     public void doSYST(FtpRequest request, FtpWriter out) throws IOException {
         
         // reset state variables
         resetState();
         
         // and print server system info 
         String args[] = {mConfig.getSystemName()};
         out.write(mFtpStatus.getResponse(215, request, mUser, args));
     }
     
     
     /**
      * <code>TYPE &lt;SP&gt; &lt;type-code&gt; &lt;CRLF&gt;</code><br>
      *
      * The argument specifies the representation type.
      */
     public void doTYPE(FtpRequest request, FtpWriter out) throws IOException {
         
         // reset state variables
         resetState();
         
         // get type from argument
         char type = 'A';
         if (request.hasArgument()){
             type = request.getArgument().charAt(0);
         }
         
         // set it
         if (mUser.setType(type)) {
            out.write(mFtpStatus.getResponse(200, request, mUser, null));
         }
         else {
             out.write(mFtpStatus.getResponse(504, request, mUser, null));
         }
     }
     
     
     /**
      * <code>USER &lt;SP&gt; &lt;username&gt; &lt;CRLF&gt;</code><br>
      *
      * The argument field is a Telnet string identifying the user.
      * The user identification is that which is required by the
      * server for access to its file system.  This command will
      * normally be the first command transmitted by the user after
      * the control connections are made.
      */
     public void doUSER(FtpRequest request, FtpWriter out) throws IOException {
         
         // reset state variables
         resetState();
         
         // argument check
         if(!request.hasArgument()) {
            out.write(mFtpStatus.getResponse(501, request, mUser, null));
            return;  
         }         
         
         // check user login status
         mbUser = true;
         if(mUser.hasLoggedIn()) {
             if(mUser.getName().equals(request.getArgument())) {
                 out.write(mFtpStatus.getResponse(230, request, mUser, null));
                 return;
             }
             else {
                 mConfig.getConnectionService().closeConnection(mUser.getSessionId());
             }
         }

         // set user name and send appropriate message
         mUser.setName(request.getArgument());
         if(mUser.getIsAnonymous()) {
             if(mConfig.isAnonymousLoginAllowed()) { 
                 FtpRequest anoRequest = new FtpRequest(mUser.getName());
                 out.write(mFtpStatus.getResponse(331, anoRequest, mUser, null));
             }
             else {
                 out.write(mFtpStatus.getResponse(530, request, mUser, null));
                 ConnectionService conService = mConfig.getConnectionService();
                 if (conService != null) {
                    conService.closeConnection(mUser.getSessionId());
                 }
             }
         }
         else {
             out.write(mFtpStatus.getResponse(331, request, mUser, null));
         }
     }
     
}