Running jar in client from browser

Question

I need to run a jar file that should be on the client’s pc over the web and pass some parameters to this jar, I managed to do this with the exec() php:

exec('java -jar "C:\Users\Suporte01\Documents\NetBeansProjects\Printer\dist\Printer.jar" Hello', $output);
print_r($output);

but it executes the jar on the server...

EDIT

It would be something like I see some web applications do like the logmein, that opens directly from the browser a remote access program that gets installed on your computer, as can be seen below:

Is it necessary to have some service installed on the customer?

Answer 1

The exec() PHP runs a command server-side, since it is not a language client-side.

Running a JAR through the browser

To execute a jar in the browser, as you wish, what I would indicate is to use a applet, as seen in this reply and call it by javascript, as in the following example:

<applet name="myapp" archive="myjar.jar" code="com.company.MyApplet"/>
<script>
   var result = myapp.foo();
</script>

Running a JAR that is on the client’s computer by Internet Explorer

Another possibility, after seeing what you wanted from the issue issue, is to request, through javascript, that the customer turns the jar for ActiveXObject, as can be seen here. The example to run is this:

function RunExe(){  
  var w = new ActiveXObject("WScript.Shell");
  var myJar = 'C://WindowJar.jar'; //exemplo
  w.run(myJar);//Roda o jar
  return true;
}

If you want to work some return of the executed file, you can use the following example:

function RunExe(){  
  var w = new ActiveXObject("WScript.Shell");
  var myJar = 'C://WindowJar.jar'; //exemplo
  var ex = w.run(myJar);//Roda o jar
  var ret = "";
  //lê a saída do jar
  while (!ex.StdOut.AtEndOfStream) {
    ret += ex.StdOut.ReadLine();
  }
  //Dá um alert no retorno
  alert(ret)
  return true;
}

Running a JAR that is on the client’s computer using protocols

Another alternative, not indicated for safety reasons, is to use URL protocols, which means tampering with the records of the target machine. According to this example, it is possible to achieve this objective as follows:

Create a personified protocol

[HKEY_CLASSES_ROOT\protocolname]
@="URL: descricao"
"URL Protocol"=""

[HKEY_CLASSES_ROOT\protocolname\shell]

[HKEY_CLASSES_ROOT\protocolname\shell\open]

[HKEY_CLASSES_ROOT\protocolname\shell\open\command]
@="\"C:\\Path to\\Jar\\myJar.jar\" %1"

Using a reference tag in HTML

<a href="protocolname:parameter-value">link</a>

However, the following may be removed from the abovementioned documentation::

Security Alert Applications that Handle URL protocols must consider how to Respond to Malicious data. Because Handler Applications can receive data from untrusted sources, the URL and other Parameter values passed to the application may contain Malicious data that Attempts to exploit the Handling application.

In free translation:

Security Alert Applications that manipulate URL protocols should consider how to respond to malicious data. Because the application handler may receive data from unreliable sources, the URL or other parameter values passed to the application may contain malicious data that tries to exploit the manipulated application.

Therefore, if it is not strictly necessary to use another browser, I recommend using Internet Explorer with the ActiveXObject, for being simpler and less dangerous than creating a custom protocol.

Answer 2

To run a JAR on the client you have some options:

• Java Web Start - http://en.wikipedia.org/wiki/Java_Web_Start;
• Java Applet - http://en.wikipedia.org/wiki/Java_applet.

This site contains comparisons between the two methods: http://mindprod.com/jgloss/javawebstart.html#APPLETSVSJWS.

It’s all in English, so I’ll try to enumerate the main differences and similarities here:

• Both run in a "restricted" environment if the JAR is not digitally signed;
• In order to access restricted areas, you need to describe what you will do, and sign the JAR;
• An applet runs in the browser, Java web start looks like a remote application, but it is downloaded from a server automatically.

The last option would be to "give" the JAR to the client and ask it to run directly on the client, and you could access your server to upload the information you need - in this case, your JAR would have unrestricted access to what the user can see (at least without the restrictions of a Java Web Start applet or application).

Answer 3

The jar at all times will run on the server side. What you have to do is capture the execution output and send it to the client side.

I think the wisest, in this case, would be to put your jar inside a web service, and this service offer a REST API for other services to talk to it via HTTP.