# String filtering.
#
# Author:Just van den Broecke
from stetl.component import Config
from stetl.util import Util
from stetl.filter import Filter
from stetl.packet import FORMAT
log = Util.get_log("stringfilter")
[docs]
class StringFilter(Filter):
"""
Base class for any string filtering
"""
# Constructor
def __init__(self, configdict, section, consumes, produces):
Filter.__init__(self, configdict, section, consumes, produces)
[docs]
def invoke(self, packet):
if packet.data is None:
return packet
return self.filter_string(packet)
def filter_string(self, packet):
pass
[docs]
class StringSubstitutionFilter(StringFilter):
"""
String filtering using Python advanced String formatting.
String should have substitutable values like {schema} {foo}
format_args should be of the form format_args = schema:test foo:bar ...
consumes=FORMAT.string, produces=FORMAT.string
"""
[docs]
@Config(ptype=str, default=':', required=False)
def separator(self):
"""
Provides the separator to split the format argument names from their values.
"""
pass
# Constructor
def __init__(self, configdict, section):
StringFilter.__init__(self, configdict, section, consumes=FORMAT.string, produces=FORMAT.string)
# Convert string to dict: http://stackoverflow.com/a/1248990
self.format_args_dict = Util.string_to_dict(self.format_args, self.separator)
def filter_string(self, packet):
# String substitution based on Python String.format()
packet.data = packet.data.format(**self.format_args_dict)
return packet
[docs]
class StringConcatFilter(StringFilter):
"""
Concatenates a specified string with the input string (packet.data) either/or as prefix (prepend)
or postfix (append) and outputs that concatenation.
consumes=FORMAT.string, produces=FORMAT.string
"""
[docs]
@Config(ptype=str, default=None, required=False)
def append_string(self):
"""
String to be appended.
Example: append_string = /002PND150904.xml
"""
pass
[docs]
@Config(ptype=str, default=None, required=False)
def prepend_string(self):
"""
String to be prepended.
Example: prepend_string = /vsizip/
"""
pass
# Constructor
def __init__(self, configdict, section):
StringFilter.__init__(self, configdict, section, consumes=FORMAT.string, produces=FORMAT.string)
def filter_string(self, packet):
if not packet.data:
return
if self.append_string:
packet.data = packet.data + self.append_string
if self.prepend_string:
packet.data = self.prepend_string + packet.data
return packet