MATLAB: Communicating with an external program

external programjava robotlinuxsystem

I am using a program called stp found here: http://scedc.caltech.edu/research-tools/downloads.html

Essentially what I am trying to do is within my matlab script have it use stp and request downloads of data that I have outlined in the script. The issue is from what I have found so far, system() doesn't allow me to continually communicate with the program (as in, send it additional commands).

stp cannot be called with any additional options or already telling it what file you want it to send you, you have to wait for it to connect first, and then send a request. My biggest problem is that once I send the command to run stp matlab sits and waits for it, but it's really waiting for another input itself. So when I run it I will get:

>> stprun %example name of script that at one point has a system('stp') command
STP: connected to caltech... etc, a lot of other stuff. basically what I would see if I ran this from any terminal.
STP>

And that's basically where it stops and waits. I don't know how to give additional inputs into "STP>", which is waiting for inputs, because matlab is also waiting for a return. I have to manually type "exit" and then hit enter which will give matlab nothing back and then the script will fail. I don't really care about a return, I just want to be able to tell STP what to do, and then have the script continue. Like send keypresses to the terminal somehow, once I start STP.

If it matters any, I'm running this on Linux.

Best Answer

There is a popen() in the File Exchange that can be used in Linux and OS-X . It does not support bidirectional transfers, but if you do not need to analyze the responses then you should be okay by just redirecting the output to a file (and possibly reading the file afterwards.)

On the other hand, if it is just a matter of sending input to a command line program without needing to interact with it, then there is a much easier way: write all of the desired commands into a file, and then when you system() redirect standard input from the file.

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MATLAB: Parse web data using JS and Google DevTools API into MATLAB App

As this answer, there is no direct way to acquire what you want. But there is an indirect way, by simulating keyboard press, mouse movement and mouse clicking. Here's an example (platform: Windows) for copying elements in the Chrome DevTools into Matlab Workplace and perhaps you can modify it accordingly.

system('start chrome "https://www.google.com/"');
import java.awt.*;
import java.awt.event.*;
% press F12 to activate Chrome DevTools
rob=Robot; % Create a Robot-object to do the key-pressing
rob.keyPress(KeyEvent.VK_F12)
rob.keyRelease(KeyEvent.VK_F12)
pause(2);
% move mouse cursor to where you want
mouse = Robot;
mouse.mouseMove(80,550); % pixel position on your screen. modify accordingly.
pause(1);
% right click to show menu
mouse.mousePress(InputEvent.BUTTON3_MASK);
pause(0.5);
mouse.mouseRelease(InputEvent.BUTTON3_MASK);
% move a little bit to activate second-level menu
for i=1:16
    mouse.mouseMove(174+i,300); % modify accordingly

    pause(0.0001);
end
pause(2);
% move the cursor to the second-level menu
for i=1:6
    mouse.mouseMove(359+i,335); % modify accordingly
    pause(0.0001);
end
pause(2);
% left click to do copy
mouse.mousePress(InputEvent.BUTTON2_MASK);    %left click press
pause(0.5);
mouse.mouseRelease(InputEvent.BUTTON2_MASK);   %left click release
% load the copied text into Matlab workspace
str=clipboard('paste');

To my experience, It might fail sometimes. So, not efficient, but hope it is helpful.

Acknowledgements :

MATLAB: How to programmatically control mouse motion and clicks with MATLAB

The ability to control mouse pointer position, motion and clicks is not available in MATLAB. To work around this issue, you can use the Java class java.awt.Robot which has this ability. Please note that this approach is not documented and hence MathWorks does not guarantee that the approach will be successful.

Below is a simple example that illustrates how you can move the mouse with MATLAB code using Java functionality. Note that we are unable to provide support for Java classes directly as they are not products of MathWorks. For further assistance regarding the Java classes and methods, refer to the following Java documentation page:

http://java.sun.com/j2se/1.5.0/docs/api/java/awt/Robot.html

The following MATLAB code example demonstrates how one can programmatically control mouse motion using the java.awt.Robot class to move the mouse diagonally across the screen. First, import the class into MATLAB, create an object of this type, and then execute the mouseMove method in a loop to simulate motion.

import java.awt.Robot;
mouse = Robot;
mouse.mouseMove(0, 0);
screenSize = get(0, 'screensize');
for i = 1: screenSize(4)
    mouse.mouseMove(i, i);
    pause(0.00001);
end

The following example demonstrates how one can programmatically click the right mouse button to bring up the context menu. Again, import the required Java classes, create an object of this type, and then use the mousePress and mouseRelease functions to simulate a click. Before executing this code, place the mouse over a portion of the screen where a context menu can appear.

import java.awt.Robot;
import java.awt.event.*;
mouse = Robot;
mouse.mousePress(InputEvent.BUTTON3_MASK);
mouse.mouseRelease(InputEvent.BUTTON3_MASK);

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Clicking on specific pixels on the screen