https://www.bignerdranch.com/blog/hijacking-for-fun-and-profit/
I have found this great code from Oscar Hernández Suárez:
https://groups.google.com/d/msg/harbour-users/oktsDgxmSKs/1YNBsuvHM6kJ
hb_processOpen() lets us manage pipes from Harbour
Hello.
This is an proof of concept of using an interface to communicate with a Java application using JSON.
----8<----
REQUEST HB_GT_STD_DEFAULT
PROCEDURE Main()
LOCAL hProcess
LOCAL hStdIn
LOCAL hStdOut
LOCAL hStdErr
LOCAL nSize := 1024
LOCAL cBuffer
LOCAL nReadedErr
LOCAL nReadedOut
LOCAL hInput := { => }
LOCAL n
LOCAL hPerson
LOCAL hDecode
LOCAL cInput
LOCAL cError := ""
LOCAL cOutput := ""
hInput[ "id" ] := 1001
hInput[ "list" ] := {}
FOR n := 1 TO 1000
hPerson := { => }
hPerson[ "name" ] := "John"
hPerson[ "surname" ] := "Smith" + Chr( 13 ) + Chr( 10 ) + " and Smith"
AAdd( hInput[ "list" ], hPerson )
NEXT
?
BEGIN SEQUENCE
cInput := hb_JsonEncode( hInput, .f. ) + Chr( 10 )
? "INPUT:", Len( cInput )
hProcess := hb_processOpen( "java.exe -cp JSON.jar;. HJAVA", @hStdIn, @hStdOut, @hStdErr, .t. )
? "WRITE:", FWrite( hStdIn, cInput )
DO WHILE .T.
? "WAITING..."
cBuffer := Space( nSize )
nReadedErr := hb_PRead( hStdErr, @cBuffer, nSize, 0 )
IF nReadedErr > 0
cErr += Left( cBuffer, nReadedErr )
ENDIF
cBuffer := Space( nSize )
nReadedOut := hb_PRead( hStdOut, @cBuffer, nSize, 0 )
IF nReadedOut > 0
cOutput += Left( cBuffer, nReadedOut )
ENDIF
IF nReadedErr < 0 .AND. nReadedOut < 0
EXIT
ENDIF
ENDDO
IF Len( cOutput ) > 0
hDecode := { => }
hb_JsonDecode( cOutput, @hDecode )
? hb_JsonEncode( hDecode, .t. )
ENDIF
IF Len( cError ) > 0
? cError
ENDIF
ALWAYS
hb_processClose( hProcess, .t. ) // kill if needed
? "ret=" + hb_ntos( hb_processValue( hProcess ) ) // wait and return exit code
FClose( hStdIn )
FClose( hStdOut )
FClose( hStdErr )
END SEQUENCE
RETURN
---->8----
Source "HJAVA.java":
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import java.util.Scanner; // JRE 1.5
import org.json.JSONObject;
import org.json.JSONException;
class HJAVA
{
public static void main( String[] args )
{
Scanner scanner = new Scanner( System.in );
String line = scanner.nextLine();
String result;
try
{
JSONObject json = new JSONObject( line );
json.put( "status", 200 );
json.put( "status_text", "OK" );
resultado = json.toString();
}
catch ( JSONException e )
{
try
{
JSONObject json = new JSONObject();
json.put( "status", 500 );
json.put( "status_text", e.toString() );
result = json.toString();
}
catch ( JSONException ee )
{
result = "";
}
}
System.out.print( result );
System.exit( 0 );
}
}
---->8----
A problem I've seen is when calling hb_ProcessClose() in Windows, if the process executes other processes, they are not finished. We should use the winapi TerminateJobObject and similar.
Sorry for the example so cumbersome, i have little time available and I could not reduce it more. I hope you can get the idea.
Regards.
