MatlabServer.m

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% MatlabServer
%
% This scripts starts a minimalistic MATLAB "server".
%
% When started, the server listens for connections at port 9999 or the
% port number specified by the environment variable 'MATLABSERVER_PORT'.
%
% Troubleshooting: If not working out of the box, add this will to the 
% MATLAB path. Make sure InputStreamByteWrapper.class is in the same 
% directory as this file!
%
% Requirements:
% This requires MATLAB with Java support, i.e. MATLAB v6 or higher.
%
% Author: Henrik Bengtsson, 2002-2016
%
% References:
% [1] http://www.mathworks.com/access/helpdesk/help/techdoc/
%                                     matlab_external/ch_jav34.shtml#49439
% [2] http://staff.science.uva.nl/~horus/dox/horus2.0/user/
%                                                  html/n_installUnix.html
% [3] http://www.mathworks.com/access/helpdesk/help/toolbox/
%                                              modelsim/a1057689278b4.html
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
fprintf(2, 'Running MatlabServer v3.5.9-9000\n');

%  addpath R/R_LIBS/linux/library/R.matlab/misc/

% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
% MATLAB version-dependent setup
% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
% Identify major version of Matlab
MatlabServer_tmp_hasMajor = eval('length(regexp(version, ''^[0-9]'')) ~= 0', '0');
if (MatlabServer_tmp_hasMajor)
  MatlabServer_tmp_verParts = sscanf(version, '%d.');
  MatlabServer_tmp_verMajor = MatlabServer_tmp_verParts(1);
  clear MatlabServer_tmp_verParts;
else 
  MatlabServer_tmp_verMajor = -1;
end
clear MatlabServer_tmp_hasMajor;

if (MatlabServer_tmp_verMajor < 6)
  % Java is not available/supported
  error('MATLAB v5.x and below is not supported.');
elseif (MatlabServer_tmp_verMajor == 6)
  fprintf(2, 'MATLAB v6.x detected.\n');
  % Default save option
  MatlabServer_saveOption = '';
  % In MATLAB v6 only the static Java CLASSPATH is supported. It is
  % specified by a 'classpath.txt' file. The default one can be found
  % by which('classpath.txt'). If a 'classpath.txt' exists in the 
  % current(!) directory (that MATLAB is started from), it *replaces*
  % the global one. Thus, it is not possible to add additional paths;
  % the global ones has to be copied to the local 'classpath.txt' file.
  %
  % To do the above automatically from R, does not seem to be an option.
else
  fprintf(2, 'MATLAB v7.x or higher detected.\n');
  % MATLAB v7 and above saves compressed files, which is not recognized
  % by R.matlab's readMat(); force saving in old format.
  MatlabServer_saveOption = '-V6';
  fprintf(2, 'Saving with option -V6.\n');

  % In MATLAB v7 and above both static and dynamic Java CLASSPATH:s exist.
  % Using dynamic ones, it is possible to add the file
  % InputStreamByteWrapper.class to CLASSPATH, given it is
  % in the same directory as this script.
  javaaddpath({fileparts(which('MatlabServer'))});
  fprintf(2, 'Added InputStreamByteWrapper to dynamic Java CLASSPATH.\n');
end
clear MatlabServer_tmp_verMajor;


% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
% Import Java classes
% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
import java.io.*;
import java.net.*;


% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
% If an old MATLAB server is running, close it
% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
% If a server object exists from a previous run, close it.
if (exist('MatlabServer_server'))
  close(MatlabServer_server); 
  clear MatlabServer_server;
end

% If an input stream exists from a previous run, close it.
if (exist('MatlabServer_is'))
  close(MatlabServer_is);
  clear MatlabServer_is;
end

% If an output stream exists from a previous run, close it.
if (exist('MatlabServer_os'))
  close(MatlabServer_os);
  clear MatlabServer_os;
end

fprintf(2, '----------------------\n');
fprintf(2, 'MATLAB server started!\n');
fprintf(2, '----------------------\n');

fprintf(2, 'MATLAB working directory: %s\n', pwd);


% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
% Initiate server socket to which clients may connect
% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
MatlabServer_port = getenv('MATLABSERVER_PORT');
if (length(MatlabServer_port) > 0)
  MatlabServer_port = str2num(MatlabServer_port);
else
  % Try to open a server socket on port 9999
  MatlabServer_port = 9999;
end

% Ports 1-1023 are reserved for the Internet Assigned Numbers Authority.
% Ports 49152-65535 are dynamic ports for the OS. [3]
if (MatlabServer_port < 1023 | MatlabServer_port > 65535)
  error('Cannot not open connection. Port (''MATLABSERVER_PORT'') is out of range [1023,65535]: %d', MatlabServer_port);
end

fprintf(2, 'Trying to open server socket (port %d)...', MatlabServer_port);
MatlabServer_server = java.net.ServerSocket(MatlabServer_port);
fprintf(2, 'done.\n');


% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
% Wait for client to connect
% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
% Create a socket object from the ServerSocket to listen and accept
% connections.
% Open input and output streams

% Wait for the client to connect
fprintf(2, 'Waiting for client to connect (port %d)...', MatlabServer_port);
MatlabServer_clientSocket = accept(MatlabServer_server);
fprintf(2, 'connected.\n');

% ...client connected.
MatlabServer_is = java.io.DataInputStream(getInputStream(MatlabServer_clientSocket));
MatlabServer_os = java.io.DataOutputStream(getOutputStream(MatlabServer_clientSocket));



% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
% The MATLAB server state machine
% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
% Commands
MatlabServer_commands = {'eval', 'send', 'receive', 'send-remote', 'receive-remote', 'echo', 'evalc'};

MatlabServer_lasterr = [];
MatlabServer_variables = [];

% As long as we receive data, echo that data back to the client.
MatlabServer_state = 0;
while (MatlabServer_state >= 0),
  if (MatlabServer_state == 0)
    MatlabServer_tmp_cmd = readByte(MatlabServer_is);
    fprintf(2, 'Received cmd: %d\n', MatlabServer_tmp_cmd);
    if (MatlabServer_tmp_cmd < -1 | MatlabServer_tmp_cmd > length(MatlabServer_commands))
      fprintf(2, 'Unknown command code: %d\n', MatlabServer_tmp_cmd);
    else
      MatlabServer_state = MatlabServer_tmp_cmd;
    end
    clear MatlabServer_tmp_cmd;

  %-------------------
  % 'evalc'
  %-------------------
  elseif (MatlabServer_state == strmatch('evalc', MatlabServer_commands, 'exact'))
    MatlabServer_tmp_bfr = char(readUTF(MatlabServer_is));
    fprintf(2, '"evalc" string: "%s"\n', MatlabServer_tmp_bfr);
    try 
      MatlabServer_tmp_bfr = sprintf(MatlabServer_tmp_bfr);
      MatlabServer_tmp_result = evalc(MatlabServer_tmp_bfr); 
      writeByte(MatlabServer_os, 0);
      fprintf(2, 'Sent byte: %d\n', 0);
      writeUTF(MatlabServer_os, MatlabServer_tmp_result);
      fprintf(2, 'Sent UTF: %s\n', MatlabServer_tmp_result);
      flush(MatlabServer_os);
      clear MatlabServer_tmp_result;
    catch
      MatlabServer_lasterr = sprintf('Failed to evaluate expression ''%s''.', MatlabServer_tmp_bfr);
      fprintf(2, 'EvaluationException: %s\n', MatlabServer_lasterr);
      writeByte(MatlabServer_os, -1);
      fprintf(2, 'Sent byte: %d\n', -1);
      writeUTF(MatlabServer_os, MatlabServer_lasterr);
      fprintf(2, 'Sent UTF: %s\n', MatlabServer_lasterr);
      flush(MatlabServer_os);
    end
    flush(MatlabServer_os);
    MatlabServer_state = 0;
    clear MatlabServer_tmp_bfr;

  %-------------------
  % 'eval'
  %-------------------
  elseif (MatlabServer_state == strmatch('eval', MatlabServer_commands, 'exact'))
    MatlabServer_tmp_bfr = char(readUTF(MatlabServer_is));
    fprintf(2, '"eval" string: "%s"\n', MatlabServer_tmp_bfr);
    try 
      eval(MatlabServer_tmp_bfr); 
      writeByte(MatlabServer_os, 0);
      fprintf(2, 'Sent byte: %d\n', 0);
      flush(MatlabServer_os);
    catch
      MatlabServer_lasterr = sprintf('Failed to evaluate expression ''%s''.', MatlabServer_tmp_bfr);
      fprintf(2, 'EvaluationException: %s\n', MatlabServer_lasterr);
      writeByte(MatlabServer_os, -1);
      fprintf(2, 'Sent byte: %d\n', -1);
      writeUTF(MatlabServer_os, MatlabServer_lasterr);
      fprintf(2, 'Sent UTF: %s\n', MatlabServer_lasterr);
      flush(MatlabServer_os);
    end
    flush(MatlabServer_os);
    MatlabServer_state = 0;
    clear MatlabServer_tmp_bfr;
  
  %-------------------
  % 'send'
  %-------------------
  elseif (MatlabServer_state == strmatch('send', MatlabServer_commands, 'exact'))
    MatlabServer_tmp_tmpname = sprintf('%s_%d.mat', tempname, MatlabServer_port);
    MatlabServer_tmp_expr = sprintf('save(MatlabServer_tmp_tmpname, ''%s''', MatlabServer_saveOption);
    MatlabServer_tmp_ok = 1;
    for MatlabServer_tmp_k=1:length(MatlabServer_variables),
      MatlabServer_tmp_variable = MatlabServer_variables{MatlabServer_tmp_k};
      if (exist(MatlabServer_tmp_variable) ~= 1)
        MatlabServer_lasterr = sprintf('Variable ''%s'' not found.', MatlabServer_tmp_variable);
        fprintf(2, '%s\n', MatlabServer_lasterr);
        MatlabServer_tmp_ok = 0;
        break;
      end;
      MatlabServer_tmp_expr = sprintf('%s, ''%s''', MatlabServer_tmp_expr, MatlabServer_tmp_variable);
    end;

    MatlabServer_tmp_expr = sprintf('%s)', MatlabServer_tmp_expr);
    if (~MatlabServer_tmp_ok)
      writeInt(MatlabServer_os, -1);
      writeUTF(MatlabServer_os, MatlabServer_lasterr);
    else
      fprintf(2, '%s\n', MatlabServer_tmp_expr);
      eval(MatlabServer_tmp_expr);
      writeInt(MatlabServer_os, 0); % Here anything but -1 means "success"
      writeUTF(MatlabServer_os, MatlabServer_tmp_tmpname);
    end
    
    MatlabServer_tmp_answer = readByte(MatlabServer_is);
    fprintf(2, 'answer=%d\n', MatlabServer_tmp_answer);
    
    MatlabServer_state = 0;
    clear MatlabServer_tmp_name MatlabServer_tmp_expr MatlabServer_tmp_ok MatlabServer_tmp_answer;

  %-------------------
  % 'send-remote'
  %-------------------
  elseif (MatlabServer_state == strmatch('send-remote', MatlabServer_commands, 'exact'))
    MatlabServer_tmp_tmpname = sprintf('%s_%d.mat', tempname, MatlabServer_port);
    MatlabServer_tmp_expr = sprintf('save(MatlabServer_tmp_tmpname, ''%s''', MatlabServer_saveOption);
    MatlabServer_tmp_ok = 1;
    for MatlabServer_tmp_k=1:length(MatlabServer_variables),
      MatlabServer_tmp_variable = MatlabServer_variables{MatlabServer_tmp_k};
      if (exist(MatlabServer_tmp_variable) ~= 1)
        MatlabServer_lasterr = sprintf('Variable ''%s'' not found.', MatlabServer_tmp_variable);
        fprintf(2, '%s\n', MatlabServer_lasterr);
        MatlabServer_tmp_ok = 0;
        break;
      end;
      MatlabServer_tmp_expr = sprintf('%s, ''%s''', MatlabServer_tmp_expr, MatlabServer_tmp_variable);
    end;
    clear MatlabServer_tmp_k MatlabServer_tmp_variable;

    MatlabServer_tmp_expr = sprintf('%s)', MatlabServer_tmp_expr);
    if (~MatlabServer_tmp_ok)
      writeInt(MatlabServer_os, -1);
      writeUTF(MatlabServer_os, MatlabServer_lasterr);
    else
      fprintf(2, '%s\n', MatlabServer_tmp_expr);
      eval(MatlabServer_tmp_expr);
      MatlabServer_tmp_file = java.io.File(MatlabServer_tmp_tmpname);
      MatlabServer_tmp_maxLength = length(MatlabServer_tmp_file);
      clear MatlabServer_tmp_file;
      writeInt(MatlabServer_os, MatlabServer_tmp_maxLength); % Here anything but -1 means "success"
      fprintf(2, 'Send int: %d (maxLength)\n', MatlabServer_tmp_maxLength);
      MatlabServer_tmp_fid = fopen(MatlabServer_tmp_tmpname, 'r');
      MatlabServer_tmp_count = 1;
      while (MatlabServer_tmp_count ~= 0)
        [MatlabServer_tmp_bfr, MatlabServer_tmp_count] = fread(MatlabServer_tmp_fid, 65536, 'int8');
        if (MatlabServer_tmp_count > 0)
          write(MatlabServer_os, MatlabServer_tmp_bfr);
        end;
      end;
      fclose(MatlabServer_tmp_fid);
      fprintf(2, 'Send buffer: %d bytes.\n', MatlabServer_tmp_maxLength);
      delete(MatlabServer_tmp_tmpname);
      clear MatlabServer_tmp_bfr MatlabServer_tmp_count MatlabServer_tmp_maxLength MatlabServer_tmp_fid MatlabServer_tmp_tmpname;
    end
    flush(MatlabServer_os);
    
    MatlabServer_tmp_answer = readByte(MatlabServer_is);
    fprintf(2, 'answer=%d\n', MatlabServer_tmp_answer);
    
    MatlabServer_state = 0;
    clear MatlabServer_tmp_name MatlabServer_tmp_expr MatlabServer_tmp_ok MatlabServer_tmp_answer;  

  %-------------------
  % 'receive-remote'
  %-------------------
  elseif (MatlabServer_state == strmatch('receive-remote', MatlabServer_commands, 'exact'))
    MatlabServer_tmp_len = readInt(MatlabServer_is);
    fprintf(2, 'Will read MAT file structure of length: %d bytes.\n', MatlabServer_tmp_len);

    MatlabServer_tmp_reader = InputStreamByteWrapper(4096);
    MatlabServer_tmp_bfr = [];
    MatlabServer_tmp_count = 1;
    while (MatlabServer_tmp_len > 0 & MatlabServer_tmp_count > 0)
      MatlabServer_tmp_count = MatlabServer_tmp_reader.read(MatlabServer_is, min(4096, MatlabServer_tmp_len));
      if (MatlabServer_tmp_count > 0)
        MatlabServer_tmp_bfr = [MatlabServer_tmp_bfr; MatlabServer_tmp_reader.bfr(1:MatlabServer_tmp_count)];
        MatlabServer_tmp_len = MatlabServer_tmp_len - MatlabServer_tmp_count;
      end;
    end;

    clear MatlabServer_tmp_reader MatlabServer_tmp_count MatlabServer_tmp_len;

    MatlabServer_tmp_tmpfile = sprintf('%s_%d.mat', tempname, MatlabServer_port);
    MatlabServer_tmp_fh = fopen(MatlabServer_tmp_tmpfile, 'wb');
    fwrite(MatlabServer_tmp_fh, MatlabServer_tmp_bfr, 'int8');
    fclose(MatlabServer_tmp_fh);

    clear MatlabServer_tmp_fh MatlabServer_tmp_bfr;
    
    load(MatlabServer_tmp_tmpfile);
    
    delete(MatlabServer_tmp_tmpfile);
    clear MatlabServer_tmp_tmpfile;
    writeByte(MatlabServer_os, 0);

    MatlabServer_state = 0;
    
  %-------------------
  % 'receive'
  %-------------------
  elseif (MatlabServer_state == strmatch('receive', MatlabServer_commands, 'exact'))
    MatlabServer_tmp_filename = char(readUTF(MatlabServer_is));
    fprintf(2, 'Will read MAT file: "%s"\n', MatlabServer_tmp_filename);
    load(MatlabServer_tmp_filename);
    clear MatlabServer_tmp_filename;
    writeByte(MatlabServer_os, 0);
    MatlabServer_state = 0;
    clear MatlabServer_tmp_filename;
  end
end


% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
% Shutting down the MATLAB server
% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

fprintf(2, '-----------------------\n');
fprintf(2, 'MATLAB server shutdown!\n');
fprintf(2, '-----------------------\n');
writeByte(MatlabServer_os, 0);
close(MatlabServer_os);
close(MatlabServer_is);
close(MatlabServer_server);
quit;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% HISTORY:
% 2016-04-05 [v3.6.0]
% o All verbose/debug messages are outputted to stream #2 ("stderr").
% 2015-09-11 [v3.3.0]
% o Now temporary files use format <tempname>_<port>.mat.
% o Add 'MatlabServer_' prefix to all variables.
% o Add 'evalc' command.  Thanks to Rohan Shah for this.
% 2015-01-08 [v3.1.2]
% o BUG FIX: Matlab$getVariable() for a non-existing variable would
%   crash the R-to-Matlab communication if remote=FALSE.
% 2014-06-23 [v3.0.2]
% o ROBUSTNESS: Variables 'lasterr' and 'variables' are now always 
%   defined. Potential bug spotted by Steven Jaffe at Morgan Stanley.
% o Added more progress/verbose output, e.g. current working directory.
% 2014-01-21 [v2.2.0]
% o BUG FIX: The MatlabServer.m script would incorrectly consider 
%   Matlab v8 and above as Matlab v6.  Thanks to Frank Stephen at NREL
%   for reporting on this and providing a patch.
% 2013-07-11 [v1.3.5]
% o Updated messages to use 'MATLAB' instead of 'Matlab'.
% 2010-10-25 [v1.3.4]
% o BUG FIX: The MatlabServer.m script incorrectly referred to the 
%   InputStreamByteWrapper class as java.io.InputStreamByteWrapper.
%   Thanks Kenvor Cothey at GMO LCC for reporting on this.
% 2010-08-28
% o Now the MatlabServer script reports its version when started.
% 2010-08-27
% o BUG FIX: Now MatlabServer.m saves variables using the function form,
%   i.e. save().  This solves the problem of having single quotation marks
%   in the pathname. Thanks Michael Q. Fan at NC State University for 
%   reporting this problem.
% 2009-08-25
% o BUG FIX: Started to get the error "Undefined function or method
%   'ServerSocket' for input arguments of type 'double'.".  It seems like
%   import java.net.* etc does not work. A workaround is to specify the
%   full path for all Java classes, e.g. java.net.ServerSocket.
%   Thanks Nicolas Stadler for reporting this issue.
% 2006-12-28
% o Extended the accepted range of ports from [1023,49151] to [1023,66535].
% 2006-05-08
% o BUG FIX: The error message string for reporting port out of range
%   was invalid and gave the error '... Line: 109 Column: 45 ")" expected, 
%   "identifier" found.'.  Thanks Alexander Nervedi for reporting this.
% 2006-01-21
% o Now an error is thrown if port number is out of (safe) range.
% o Added option to specify the port number via the system environment 
%   variable MATLABSERVER_PORT, after request by Wang Yu, Iowa State Univ.
% 2005-03-08
% o BUG FIX: substring() is not recognized by MATLAB v7. Using regexp()
%   which works in MATLAB 6.5 and 7. Workaround eval('try', 'catch').
%   Thanks Patrick Drechsler, University of Wuerzburg for the bug report.
% 2005-02-24
% o Now the dynamic Java classpath is set for MATLAB v7 or higher. This
%   will simplify life for MATLAB v7 users.
% 2005-02-22
% o Added javaaddpath() to include InputStreamByteWrapper.class.
%   Thanks Yichun Wei for feedback and great suggestions.
% 2005-02-11
% o If MATLAB v7 or higher is detected, all MAT structures are saved with
%   option '-V6' so readMat() in R.matlab can read them.
% 2002-09-02 [or maybe a little bit earlier]
% o Created.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%