Invoke PHP code from Java (Scala) and get result

Question

This seems to have been asked in several places and has been marked as "closed" and "off-topic". However, people seem to have this problem constantly

invoking a php method from java (closed)

Calling PHP from Java (closed)

How can I run PHP code within a Java application? (closed)

This answer in the last question partly answers this but does not clarify how to read the outputs.

I finally found the answer to the question:

How do I run a PHP program from within Java and obtain its output? To give more context, someone has given me a PHP file containing code for some method foo that returns a string. How do we invoke this from JVM?

Searching on Google is not helpful as all articles I found don't explain how to call PHP from Java but rather Java from PHP.

The answer below explains how to do this using the PHP/Java bridge.

The answer is in Scala but would be easy to read for Java programmers.

Answer 1

Code created from this SO answer and this example:

package javaphp

import javax.script.ScriptEngineManager
import php.java.bridge._
import php.java.script._
import php.java.servlet._

object JVM{ // shared object for PHP/JVM communication
  var out = ""
  def put(s:String) = {
    out = s
  }
}

object Test extends App {
  val engine = (new ScriptEngineManager).getEngineByExtension("php")  
  val oldCode = """
    <?php
        function foo() {
            return 'hello';
            // some code that returns string
        }
    ?>
  """
  val newCode = """
    <?php
        $ans = foo();
        java('javaphp.JVM')->put($ans);
    ?>
  """+oldCode

  // below evaluates and returns
  JVM.out = "" //reset shared output
  engine.eval(newCode)
  println("output is : "+JVM.out) // prints hello
}

To run this file:

Install PHP, Scala and set path correctly. Then create a file php.scala with the above code. Then run:

scalac php.scala

and

scala javaphp.Test