Support reading PEM files in TLSLite

third_party/tlslite/tlslite/X509CertChain.py

Index: third_party/tlslite/tlslite/X509CertChain.py
diff --git a/third_party/tlslite/tlslite/X509CertChain.py b/third_party/tlslite/tlslite/X509CertChain.py
index 6bb503e43eefa9f01f9c7ec89cb9393f35b1148a..47de9882c1e0337ab72cc2f1cdbcf7dfabbb081a 100644
--- a/third_party/tlslite/tlslite/X509CertChain.py
+++ b/third_party/tlslite/tlslite/X509CertChain.py
@@ -1,6 +1,7 @@
 """Class representing an X.509 certificate chain."""
 
 from utils import cryptomath
+from X509 import X509
 
 class X509CertChain:
     """This class represents a chain of X.509 certificates.
@@ -24,6 +25,65 @@ class X509CertChain:
         else:
             self.x509List = []
 
+    def parseChain(self, s):

[Nico, 2012/02/29 00:33:34]

Could use a basic unit test

+        """Parse a PEM-encoded X.509 certificate file chain file.
+
+        @type s: str

[Nico, 2012/02/29 00:33:34]

s isn't a great parameter name. parameters are part of the interface and hence
should have decent names.

+        @param s: A PEM-encoded (eg: Base64) X.509 certificate file, with every
+        certificate wrapped within "-----BEGIN CERTIFICATE-----" and
+        "-----END CERTIFICATE-----" tags). Extraneous data outside such tags,
+        such as human readable representations, will be ignored.
+        """
+
+        class PEMIterator(object):
+            """Simple iterator over PEM-encoded certificates within a string.
+
+            @type s: string
+            @ivar s: A string containing PEM-encoded (Base64) certificates, with
+            every certificate wrapped within "-----BEGIN CERTIFICATE-----" and
+            "-----END CERTIFICATE-----" tags). Extraneous data outside such
+            tags, such as human readable representations, will be ignored.
+
+            @type index: integer
+            @param index: The current offset within s to begin iterating from

[Nico, 2012/02/29 00:33:34]

@ivar index?

+            """
+
+            def __init__(self, s):
+                self.s = s
+                self.index = 0
+
+            def __iter__(self):
+                return self
+
+            def next(self):
+                """Iterates and returns the next L{tlslite.X509.X509}
+                certificate in s
+
+                @rtype tlslite.X509.X509
+                """
+
+                self.index = self.s.find("-----BEGIN CERTIFICATE-----",

[Nico, 2012/02/29 00:33:34]

Make these strings "constants"?

+                                         self.index)
+                if (self.index == -1):

[Nico, 2012/02/29 00:33:34]

no parens

+                    raise StopIteration
+                end = self.s.find("-----END CERTIFICATE-----", self.index)
+                if (end == -1):

[Nico, 2012/02/29 00:33:34]

no parens

+                    raise StopIteration
+
+                certStr = self.s[self.index+len("-----BEGIN CERTIFICATE-----") :
+                                 end]
+                self.index = end + len("-----END CERTIFICATE-----")
+                bytes = cryptomath.base64ToBytes(certStr)
+                cert = X509()
+                cert.parseBinary(bytes)
+                return cert
+
+        certs = []
+        for cert in PEMIterator(s):
+            certs.append(cert)
+        self.x509List = certs

[Nico, 2012/02/29 00:33:34]

Does `self.x509List = list(PEMIerator(s))` work as well?

+        return self
+
     def getNumCerts(self):
         """Get the number of certificates in this chain.