basicConstraints support for OpenSSL X509 backend
diff --git a/docs/x509.rst b/docs/x509.rst
index 44d53a4..f17c3da 100644
--- a/docs/x509.rst
+++ b/docs/x509.rst
@@ -205,6 +205,12 @@
:raises cryptography.x509.DuplicateExtension: If more than one
extension of the same type is found within the certificate.
+ .. doctest::
+
+ >>> for ext in cert.extensions:
+ ... print(ext)
+ <Extension(oid=<ObjectIdentifier(oid=2.5.29.19, name=basicConstraints)>, critical=True, value=<BasicConstraints(ca=True, path_length=None)>)>
+
.. class:: Name
.. versionadded:: 0.8
@@ -292,6 +298,23 @@
An X.509 Extensions instance is an ordered list of extensions. The object
is iterable to get every extension.
+ .. method:: get_extension_for_oid(oid)
+
+ :param oid: An :class:`ObjectIdentifier` instance.
+
+ :returns: An instance of the extension class.
+
+ :raises cryptography.x509.ExtensionNotFound: If the certificate does
+ not have the extension requested.
+
+ :raises cryptography.x509.UnsupportedExtension: If the certificate
+ contains an extension that is not supported.
+
+ .. doctest::
+
+ >>> cert.extensions.get_extension_for_oid(x509.OID_BASIC_CONSTRAINTS)
+ <Extension(oid=<ObjectIdentifier(oid=2.5.29.19, name=basicConstraints)>, critical=True, value=<BasicConstraints(ca=True, path_length=None)>)>
+
.. class:: Extension
.. versionadded:: 0.9
@@ -546,6 +569,17 @@
Returns the OID.
+.. class:: ExtensionNotFound
+
+ This is raised when calling :meth:`Extensions.get_extension_for_oid` with
+ an extension OID that is not present in the certificate.
+
+ .. attribute:: oid
+
+ :type: :class:`ObjectIdentifier`
+
+ Returns the OID.
+
.. _`public key infrastructure`: https://en.wikipedia.org/wiki/Public_key_infrastructure
.. _`TLS`: https://en.wikipedia.org/wiki/Transport_Layer_Security