rename card_data to card_key_provider.

"data" is an awfully generic term.  Anything stored on a card is data.

This specific code deals with resolving key/pin material from an
external source.

Change-Id: I4c8e1be3e766f7c0565c07b39d48abf8adc375af

pySim/card_key_provider.py

@@ -0,0 +1,117 @@
+# coding=utf-8
+"""Abstraction of card related data that can be queried from external source."""
+
+# (C) 2021 by Sysmocom s.f.m.c. GmbH
+# All Rights Reserved
+#
+# Author: Philipp Maier
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from typing import List, Dict, Optional
+
+import csv
+
+card_key_providers = [] # type: List[CardData]
+
+class CardKeyProvider(object):
+
+	VALID_FIELD_NAMES = ['ICCID', 'ADM1', 'IMSI', 'PIN1', 'PIN2', 'PUK1', 'PUK2']
+
+	# check input parameters, but do nothing concrete yet
+	def get_data(self, fields:List[str]=[], key:str='ICCID', value:str="") -> Dict[str,str]:
+		"""abstract implementation of get_data that only verifies the function parameters"""
+
+		for f in fields:
+			if (f not in self.VALID_FIELD_NAMES):
+				raise ValueError("Requested field name '%s' is not a valid field name, valid field names are: %s" %
+						 (f, str(self.VALID_FIELD_NAMES)))
+
+		if (key not in self.VALID_FIELD_NAMES):
+			raise ValueError("Key field name '%s' is not a valid field name, valid field names are: %s" %
+					 (key, str(self.VALID_FIELD_NAMES)))
+
+		return {}
+
+	def get_field(self, field:str, key:str='ICCID', value:str="") -> Optional[str]:
+		"""get a single field from CSV file using a specified key/value pair"""
+		fields = [field]
+		result = self.get(fields, key, value)
+		return result.get(field)
+
+	def get(self, fields:List[str], key:str, value:str) -> Dict[str,str]:
+		"""get fields from CSV file using a specified key/value pair"""
+		pass
+
+class CardKeyProviderCsv(CardKeyProvider):
+	"""card data class that allows the user to query against a specified CSV file"""
+	csv_file = None
+	filename = None
+
+	def __init__(self, filename:str):
+		self.csv_file = open(filename, 'r')
+		if not self.csv_file:
+			raise RuntimeError("Could not open CSV-File '%s'" % filename)
+		self.filename = filename
+
+	def get(self, fields:List[str], key:str, value:str) -> Dict[str,str]:
+		"""get fields from CSV file using a specified key/value pair"""
+		super().get_data(fields, key, value)
+
+		self.csv_file.seek(0)
+		cr = csv.DictReader(self.csv_file)
+		if not cr:
+			raise RuntimeError("Could not open DictReader for CSV-File '%s'" % self.filename)
+		cr.fieldnames = [ field.upper() for field in cr.fieldnames ]
+
+		rc = {}
+		for row in cr:
+			if row[key] == value:
+				for f in fields:
+					if f in row:
+						rc.update({f : row[f]})
+					else:
+						raise RuntimeError("CSV-File '%s' lacks column '%s'" %
+								   (self.filename, f))
+		return rc
+
+
+def card_key_provider_register(provider:CardKeyProvider, provider_list=card_key_providers):
+	"""Register a new card data provider"""
+	if not isinstance(provider, CardKeyProvider):
+		raise ValueError("provider is not a card data provier")
+	provider_list.append(provider)
+
+
+def card_key_provider_get(fields, key:str, value:str, provider_list=card_key_providers) -> Dict[str,str]:
+	"""Query all registered card data providers"""
+	for p in provider_list:
+		if not isinstance(p, CardKeyProvider):
+			raise ValueError("provider list contains provider, which is not a card data provier")
+		result = p.get(fields, key, value)
+		if result:
+			return result
+	return {}
+
+
+def card_key_provider_get_field(field:str, key:str, value:str, provider_list=card_key_providers) -> Optional[str]:
+	"""Query all registered card data providers for a single field"""
+	for p in provider_list:
+		if not isinstance(p, CardKeyProvider):
+			raise ValueError("provider list contains provider, which is not a card data provier")
+		result = p.get_field(field, key, value)
+		if result:
+			return result
+	return None
+