simple_write_content.py

###############################################################################
# Write content to an outgoing flow file using a callback
# modified from "https://community.hortonworks.com/articles/75545/executescript-cookbook-part-2.html"
# 
# This script will only write content, not read input content
#  
# output:
# Hello World!
###############################################################################

from org.apache.commons.io import IOUtils
from java.nio.charset import StandardCharsets
from org.apache.nifi.processor.io import OutputStreamCallback
 
# Define a subclass of OutputStreamCallback for use in session.write()
class PyOutputStreamCallback(OutputStreamCallback):
  def __init__(self):
        pass
  def process(self, outputStream):
    outputStream.write(bytearray('Hello World!'.encode('utf-8')))
# end class
flowFile = session.get()
if(flowFile != None):
    flowFile = session.write(flowFile, PyOutputStreamCallback())
session.transfer(flowFile, REL_SUCCESS)