#!/usr/bin/env python
#
# Extracts data from a string using a regular expression and generates a record.
#
# Author: Frank Steggink
import re
from stetl.component import Config
from stetl.filter import Filter
from stetl.packet import FORMAT
from stetl.util import Util
log = Util.get_log("regexfilter")
[docs]
class RegexFilter(Filter):
"""
Extracts data from a string using a regular expression and returns the named groups as a record.
consumes=FORMAT.string, produces=FORMAT.record
"""
# Start attribute config meta
# Applying Decorator pattern with the Config class to provide
# read-only config values from the configured properties.
[docs]
@Config(ptype=str, default=None, required=True)
def pattern_string(self):
"""
Regex pattern string. Should contain named groups.
"""
pass
# End attribute config meta
# Constructor
def __init__(self, configdict, section, consumes=FORMAT.string, produces=FORMAT.record):
Filter.__init__(self, configdict, section, consumes, produces)
self.regex_object = re.compile(self.pattern_string, re.S)
[docs]
def init(self):
log.info('Init: regex filter')
if self.pattern_string is None:
# If no pattern_string is present:
err_s = 'The pattern_string needs to be configured'
log.error(err_s)
raise ValueError('The pattern_string needs to be configured')
[docs]
def exit(self):
log.info('Exit: regex filter')
[docs]
def invoke(self, packet):
if packet.data is None:
return packet
m = self.regex_object.match(packet.data)
if m is not None:
packet.data = m.groupdict()
else:
packet.data = {}
return packet