| . About the Matlab server {R.matlab} | R Documentation |
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 http://www.mathworks.com/support/solutions/data/1-16B8X.html for more information.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% MatlabServer
%
% This scripts starts a minimalistic Matlab "server".
%
% 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, 2002-2005
%
% 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
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% addpath R/R_LIBS/linux/library/R.matlab/misc/
% Detect major Matlab version
isVersion7 = eval('length(regexp(version, ''^7'')) ~= 0', '0');
if (~isVersion7)
disp('Matlab v6.x detected.');
% Default save option
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
disp('Matlab v7.x or higher detected.');
% Matlab v7 saves compressed files, which is not recognized by
% R.matlab's readMat(); force saving in old format.
saveOption = '-V6';
disp('Saving with option -V6.');
% In Matlab v7 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'))});
disp('Added InputStreamByteWrapper to dynamic Java CLASSPATH.');
end
% Importing Java classes
import java.io.*;
import java.net.*;
% If a server object exists from a previous run, close it.
if (exist('server'))
close(server);
clear server;
end
% If an input stream exists from a previous run, close it.
if (exist('is'))
close(is);
clear is;
end
% If an output stream exists from a previous run, close it.
if (exist('os'))
close(os);
clear os;
end
fprintf(1, '----------------------\n');
fprintf(1, 'Matlab server started!\n');
fprintf(1, '----------------------\n');
% Try to open a server socket on port 9999
% Note that we can't choose a port less than 1023 if we are not
% privileged users (root)
port = 9999;
server = ServerSocket(port);
fprintf(1, 'Server socket created.\n');
% Create a socket object from the ServerSocket to listen and accept
% connections.
% Open input and output streams
% Wait for the client to connect
clientSocket = accept(server);
fprintf(1, 'Connected to client.\n');
% ...client connected.
is = DataInputStream(getInputStream(clientSocket));
%is = BufferedReader(InputStreamReader(is0));
os = DataOutputStream(getOutputStream(clientSocket));
% Commands
commands = {'eval', 'send', 'receive', 'send-remote', 'receive-remote', 'echo'};
% As long as we receive data, echo that data back to the client.
state = 0;
while (state >= 0),
if (state == 0)
cmd = readByte(is);
fprintf(1, 'Received cmd: %d\n', cmd);
if (cmd < -1 | cmd > length(commands))
fprintf(1, 'Unknown command code: %d\n', cmd);
else
state = cmd;
end
%-------------------
% 'eval'
%-------------------
elseif (state == strmatch('eval', commands, 'exact'))
bfr = char(readUTF(is));
fprintf(1, '"eval" string: "%s"\n', bfr);
try
eval(bfr);,
writeByte(os, 0);
fprintf(1, 'Sent byte: %d\n', 0);
flush(os);
catch,
fprintf(1, 'EvaluationException: %s\n', lasterr);
writeByte(os, -1);
fprintf(1, 'Sent byte: %d\n', -1);
writeUTF(os, lasterr);
fprintf(1, 'Sent UTF: %s\n', lasterr);
flush(os);
end
flush(os);
state = 0;
%-------------------
% 'send'
%-------------------
elseif (state == strmatch('send', commands, 'exact'))
tmpname = sprintf('%s.mat', tempname);
expr = sprintf('save %s %s', tmpname, saveOption);
ok = 1;
for k=1:length(variables),
variable = variables{k};
if (exist(variable) ~= 1)
lasterr = sprintf('Variable ''%s'' not found.', variable);
ok = 0;
break;
end;
expr = sprintf('%s %s', expr, variable);
end;
if (~ok)
writeInt(os, -1);
writeUTF(os, lasterr);
else
disp(expr);
eval(expr);
writeUTF(os, tmpname);
end
answer = readByte(is);
fprintf('answer=%d\n', answer);
state = 0;
%-------------------
% 'send-remote'
%-------------------
elseif (state == strmatch('send-remote', commands, 'exact'))
tmpname = sprintf('%s.mat', tempname);
expr = sprintf('save %s %s', tmpname, saveOption);
ok = 1;
for k=1:length(variables),
variable = variables{k};
if (exist(variable) ~= 1)
lasterr = sprintf('Variable ''%s'' not found.', variable);
ok = 0;
break;
end;
expr = sprintf('%s %s', expr, variable);
end;
if (~ok)
writeInt(os, -1);
writeUTF(os, lasterr);
else
disp(expr);
eval(expr);
file = File(tmpname);
maxLength = length(file);
clear file;
writeInt(os, maxLength);
fprintf(1, 'Send int: %d (maxLength)\n', maxLength);
fid = fopen(tmpname, 'r');
count = 1;
while (count ~= 0)
[bfr, count] = fread(fid, 65536, 'int8');
if (count > 0)
write(os, bfr);
% fprintf(1, 'Wrote %d byte(s).\n', length(bfr));
end;
end;
fclose(fid);
% fprintf(1, 'Wrote!\n');
fprintf(1, 'Send buffer: %d bytes.\n', maxLength);
delete(tmpname);
clear bfr, count, maxLength, fid, tmpname;
end
flush(os);
answer = readByte(is);
fprintf('answer=%d\n', answer);
state = 0;
%-------------------
% 'receive-remote'
%-------------------
elseif (state == strmatch('receive-remote', commands, 'exact'))
len = readInt(is);
fprintf(1, 'Will read MAT file structure of length: %d bytes.\n', len);
reader = InputStreamByteWrapper(4096);
bfr = [];
count = 1;
while (len > 0 & count > 0)
count = reader.read(is, min(4096, len));
if (count > 0)
bfr = [bfr; reader.bfr(1:count)];
len = len - count;
end;
end;
clear reader count len;
tmpfile = sprintf('%s.mat', tempname);
% tmpfile = 'tmp2.mat';
% disp(bfr');
% disp(tmpfile);
fh = fopen(tmpfile, 'wb');
fwrite(fh, bfr, 'int8');
fclose(fh);
clear fh, bfr;
load(tmpfile);
delete(tmpfile);
clear tmpfile;
writeByte(os, 0);
state = 0;
%-------------------
% 'receive'
%-------------------
elseif (state == strmatch('receive', commands, 'exact'))
filename = char(readUTF(is));
fprintf(1, 'Will read MAT file: "%s"\n', filename);
load(filename);
clear filename;
writeByte(os, 0);
state = 0;
end
end
fprintf(1, '-----------------------\n');
fprintf(1, 'Matlab server shutdown!\n');
fprintf(1, '-----------------------\n');
writeByte(os, 0);
close(os);
close(is);
close(server);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% HISTORY:
% 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 forfeedback 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:
2002-09-02 [or maybe a little bit earlier]
o Created.
*********************************************************************/