class JSON(Actor):
'''**A Wishbone module which converts and validates JSON.**
This module has 2 main modes:
- Validate JSON data and convert into a Python data structure.
- Convert a Python data structure into a JSON string.
Parameters:
- name (str): The instance name when initiated.
- mode (str): Determines whether the input has to be encoded, decoded or
passed through.
Can have 3 values: "encode", "decode", "pass"
Default: pass
- schema (str): The filename of the JSON validation schema to load. When no
schema is defined no validation is done.
Default: ''
Queues:
- inbox: Incoming events.
- outbox: Outgoing events.
Data which cannot be converted or which fails the validation is purged.
The schema should be in valid JSON syntax notation. JSON validation can
only be done on Python objects so you will have to convert your any JSON
data to a Python object first.
'''
def __init__(self, name, mode="pass", schema=''):
Actor.__init__(self, name)
self.name=name
self.mode=mode
self.schema=schema
if mode == "decode":
self.convert = self.__loads
elif mode == "encode":
self.convert = self.__dumps
elif mode == "pass":
self.convert = self.__pass
else:
raise Exception ("mode should be either 'encode' or 'decode'.")
if schema != "":
self.logging.debug("Validation schema defined. Doing validation.")
schema_data = self.__loadValidationSchema(schema)
self.validate = self.__validate
self.validator=Validator(schema_data)
else:
self.logging.debug("No validation schema defined. No validation.")
self.validate = self.__noValidate
def consume(self, event):
try:
event["data"] = self.convert(event["data"])
except Exception as err:
self.logging.warn("Unable to convert incoming data. Purged. Reason: %s"%(err))
return
try:
self.validate(event["data"])
except ValidationError as err:
self.logging.warn("JSON data does not pass the validation schema. Purged. Reason: %s"%(str(err).replace("\n"," > ")))
return
try:
self.queuepool.outbox.put(event)
except QueueLocked:
self.queuepool.inbox.rescue(event)
self.queuepool.outbox.waitUntilPutAllowed()
def __loadValidationSchema(self, path):
with open(path,'r') as schema:
data = ''.join(schema.readlines())
print loads(data)
return loads(data)
def __loads(self, data):
return loads(data)
def __dumps(self, data):
return dumps(data)
def __pass(self, data):
return data
def __validate(self, data):
return self.validator.validate(data)
def __noValidate(self, data):
return True
def shutdown(self):
self.logging.info('Shutdown')
