SF.net SVN: fclient: [86] trunk/sandbox/fcp/fcp2_0_uri.py

[<ju...@us...>]

Revision: 86
          http://fclient.svn.sourceforge.net/fclient/?rev=86&view=rev
Author:   jurner
Date:     2008-01-30 05:19:47 -0800 (Wed, 30 Jan 2008)

Log Message:
-----------
check keys to more depth

Modified Paths:
--------------
    trunk/sandbox/fcp/fcp2_0_uri.py

Modified: trunk/sandbox/fcp/fcp2_0_uri.py
===================================================================
--- trunk/sandbox/fcp/fcp2_0_uri.py	2008-01-29 11:28:06 UTC (rev 85)
+++ trunk/sandbox/fcp/fcp2_0_uri.py	2008-01-30 13:19:47 UTC (rev 86)
@@ -1,82 +1,93 @@
-"""Freennet Client Protocol uri"""
+"""Freennet Client Protocol uri and related methods"""
 
+import base64
 import re
+import urlparse
+#**************************************************************************************
+# freenet base64 for keys
+#**************************************************************************************
+def base64UrlsaveDecode(string):
+	"""Decodes a base64 urlsave encoded string as encoded by freenet
+	@param string: string to decode
+	@return: decoded string
+	
+	@raise TypeError: if the string can not be decoded 
+	@note: this function handles non-standard encoding as used by freenet (see: freenet/support/base64.java)
+	"""
+	# freenet uses - for + and ~ for /
+	altchars = '-~'
+	
+	# padding may be ommitted or not
+	padding = 4 - len(string) % 4
+	if padding:
+		string += '=' * padding
+	return base64.b64decode(string, altchars)
+
+#****************************************************************************************
+# freenet keys
+#
+# KeyType@32 bytes hash, 32 bytes encryption key, 5 bytes extra
+#
+# all byte components are base64 encoded. Freenet uses base64 without padding
+# and uses the following altchars for urlsave encode: - for + and ~ for /      
+# see: freenet/support/base64.java
+#
+# so a key as the user gets it to see is:
+# KeyType@43 bytes, 43 bytes, 7 bytes  ..of [A-Za-z0-9\-~]
+#
+#***************************************************************************************
+KeyPat = re.compile(
+r'''
+^(CHK | SSK | SVK | USK) @
+(
+    [a-z0-9\-~]{43},
+    [a-z0-9\-~]{43},
+    [a-z0-9\-~]{7}
+)
+''', re.I | re.X)		#TODO: ignorecase?
+
+
+def keyType(uri):
+	"""Returns the ky type of a freenet key or None if the type could not be determined"""
+	if uri.startswith('KSK@'):
+		return 'KSK'
+	result = KeyPat.match(uri)
+	if result is None:
+		return None
+	return result.group(1)
+
 #*********************************************************************
 #
 #*********************************************************************
- 
+def stripUri(uri):
+	"""Strips scheme and location parts from an uri"""
+	result = urlparse.urlsplit(uri)[2]
+	result = result.lstrip('/')
+	return result
+
+
 class Uri(object):
-	"""Wrapper class for freenet uris"""
 	
+	KeyTypeSSK = 'SSK'
+	KeyTypeKSK = 'KSK'
+	KeyTypeCHK = 'CHK'
+	KeyTypeUSK = 'USK'
+	KeyTypeSVK = 'SVK'
+	KeyTypeInvalid = ''
+	KeysTypesAll = (KeyTypeSSK, KeyTypeKSK, KeyTypeCHK, KeyTypeUSK, KeyTypeSVK)
 	
-	KeySSK = 'SSK@'
-	KeyKSK = 'KSK@'
-	KeyCHK = 'CHK@'
-	KeyUSK = 'USK@'
-	KeySVK = 'SVK@'
-	KeyUnknown = ''
-	KeysAll = (KeySSK, KeyKSK, KeyCHK, KeyUSK, KeySVK)
-				
-	ReUriPattern = re.compile('(%s.*?)(?= |\Z)' % '.*?|'.join(KeysAll), re.I)
-	ReKeyPattern = re.compile('(%s)' % '|'.join(KeysAll), re.I)
 	
-	
 	def __init__(self, uri):
-		"""
-		@param uri: uri to wrap
-		@param cvar ReUriPattern: pattern matching a freenet uri
-		@param cvar ReKeyPattern: pattern matching the key type of a freenet uri
+		self.uri = stripUri(uri)
 		
-		@note: any dfecorations prefixing the freenet part of the uri uri are stripped if possible
+		result = keyType(self.uri)
+		self.keyType = self.KeyTypeInvalid if result is None else result
+				
 		
+	def __nonzero__(self):
+		return self.keyType != self.KeyTypeInvalid
 		
-		>>> uri = FcpUri('freenet:SSK@foo/bar')
-		>>> str(uri)
-		'SSK@foo/bar'
-		>>> uri.keyType() == FcpUri.KeySSK
-		True
-		>>> uri.split()
-		('SSK@foo', 'bar')
-		>>> uri.fileName()
-		'bar'
 		
-		>>> uri = FcpUri('http://SSK@foo/bar')
-		>>> str(uri)
-		'SSK@foo/bar'
-		
-		# uris not containing freenet keys are left unchanged
-		>>> uri = FcpUri('http://foo/bar')
-		>>> str(uri)
-		'http://foo/bar'
-		>>> uri.keyType() == FcpUri.KeyUnknown
-		True
-		>>> uri.split()
-		('http://foo/bar', '')
-		>>> uri.fileName()
-		'http://foo/bar'
-		
-		"""	
-		self.uri = uri
-		
-		result = self.ReUriPattern.search(uri)
-		if result is not None:
-			self.uri = result.group(0)
-		
-	def __str__(self):
-		return str(self.uri)
-	
-	def __unicode__(self):
-		return unicode(self.uri)
-	
-	def keyType(self):
-		"""Retuns the key type of the uri
-		@return: one of the Key* consts
-		"""
-		result = self.ReKeyPattern.search(self.uri)
-		if result is not None:
-			return result.group(0).upper()
-		return self.KeyUnknown
-		
 	def split(self):
 		"""Splits the uri
 		@return: tuple(freenet-key, file-name)
@@ -86,6 +97,7 @@
 			return head, tail
 		return self.uri, ''
 		
+	
 	def fileName(self):
 		"""Returns the filename part of the uri
 		@return: str
@@ -94,4 +106,6 @@
 		if tail:
 			return tail
 		return self.uri
-	
+
+
+


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