openc2lib.types.base.record

 1import inspect
 2
 3from openc2lib.types.base.openc2_type import Openc2Type
 4
 5class Record(Openc2Type):
 6	""" OpenC2 Record
 7
 8		Implements OpenC2 Record: 
 9			>An ordered map from a list of keys with positions to values with 
10			positionally-defined semantics. Each key has a position and name, 
11			and is mapped to a type.
12
13		It expect keys to be public class attributes. All internal attributes 
14		must be kept private by prefixing it with an '_'.
15
16	"""
17	def todict(self, e):
18		""" Converts to dictionary 
19		
20			It is used to convert this object to an intermediary representation during 
21			serialization. It takes an `Encoder` argument that is used to recursively
22			serialize inner data and structures (the `Encoder` provides standard methods
23			for converting base types to dictionaries).. 
24
25			:param e: The `Encoder` that is being used.
26			:return: A dictionary compliants to the Language Specification's serialization
27			rules.
28		"""
29		objdic = vars(self)
30
31		dic = {}
32		for k,v in objdic.items():
33			# Fix keywords corresponding to variable names that clash with Python keywords
34			if isinstance(k, str) and k.endswith('_'):
35				k = k.rstrip('_')
36			# Remove empty and private elements; do not include non-string keys
37			if not v is None and not k.startswith('_') and isinstance(k, str):
38				dic[k] = v	
39
40		return e.todict(dic)
41
42	@classmethod
43	def fromdict(clstype, dic, e):
44		""" Builds instance from dictionary 
45
46			It is used during deserialization to create an openc2lib instance from the text message.
47			It takes an `Encoder` instance that is used to recursively build instances of the inner
48			objects (the `Encoder` provides standard methods to create instances of base objects like
49			strings, integers, boolean).
50
51			:param dic: The intermediary dictionary representation from which the object is built.
52			:param e: The `Encoder that is being used.
53			:return: An instance of this class initialized from the dictionary values.
54		"""
55		objdic = {}
56		# Retrieve class type for each field in the dictionary
57		fielddesc = None
58		for tpl in inspect.getmembers(clstype):
59			if tpl[0] == '__annotations__':
60				fielddesc = tpl[1]
61
62		for k,v in dic.items():
63			if k not in fielddesc:
64				raise Exception("Unknown field '" + k + "' from message")
65			objdic[k] = e.fromdict(fielddesc[k], v)
66
67
68		# A record should always have more than one field, so the following statement 
69		# should not raise exceptions
70		return clstype(**objdic)