This section gives addition details on the MATLAB server. At the end, the MatlabServer.m script and the InputStreamByteWrapper.java code is shown.
Note that you "cannot prevent MATLAB from creating a window when starting on Windows systems, but you can force the window to be hidden, by using " the option -minimize. See https://www.mathworks.com/matlabcentral/answers/102082 for more information.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% 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.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
The Java class InputStreamByteWrapper is needed in order for MATLAB to
receive data via a data stream. R sends data via a data
stream if, and only if, the connection was setup for "remote"
communication, that is, with argument remote = TRUE).
import java.io.*;/*********************************************************************
% Compile from within MATLAB with:
% !javac InputStreamByteWrapper.java
% MATLAB example that reads a file using Java code and writes it
% back to a temporary file using MATLAB code. Finally the contents
% of the new file is displayed.
reader = InputStreamByteWrapper; % Default buffer size is 4096 bytes.
in = java.io.FileInputStream('InputStreamByteWrapper.java');
bfr = [];
len = 1;
while (len > 0)
len = reader.read(in, 16); % Read 16 bytes at the time (offset=0).
if (len > 0)
bfr = [bfr; reader.bfr(1:len)]; % Add bytes to my MATLAB buffer.
end
end
close(in);
clear in, reader;
disp(bfr');
tmpfile = tempname;
fh = fopen(tmpfile, 'wb');
fwrite(fh, bfr, 'char');
fclose(fh);
type(tmpfile);
*********************************************************************/
public class InputStreamByteWrapper {
public static byte[] bfr = null;
public InputStreamByteWrapper(int capasity) {
bfr = new byte[capasity];
}
public InputStreamByteWrapper() {
this(4096);
}
public int read(InputStream in, int offset, int length) throws IOException {
return in.read(bfr, offset, length);
}
public int read(InputStream in, int length) throws IOException {
return read(in, 0, length);
}
public int read(InputStream in) throws IOException {
return in.read(bfr);
}
}
/*********************************************************************
HISTORY:
2013-07-11
o Updated comments to use 'MATLAB' instead of 'Matlab'.
2002-09-02 [or maybe a little bit earlier]
o Created.
*********************************************************************/