<div dir="ltr"><div>I&#39;ve been reading up on the different reasons why this occurs, and I appear to be following all the appropriate naming conventions. This is a custom attribute name and it uses the urn:oasis:names:tc:SAML:2.0:attrname-format:uri nameFormat.</div>
<div><br></div><div>attribute-resolver.xml:</div><div><br></div><div>&lt;resolver:AttributeDefinition xsi:type=&quot;PrincipalName&quot; xmlns=&quot;urn:mace:shibboleth:2.0:resolver:ad&quot; id=&quot;userPrincipalUsername&quot;&gt;</div>
<div>    &lt;resolver:AttributeEncoder xsi:type=&quot;SAML2String&quot; xmlns=&quot;urn:mace:shibboleth:2.0:attribute:encoder&quot; nameFormat=&quot;urn:oasis:names:tc:SAML:2.0:attrname-format:uri&quot; name=&quot;<a href="https://www.example.org/attributes/username">https://www.example.org/attributes/username</a>&quot; /&gt;</div>
<div>&lt;/resolver:AttributeDefinition&gt;</div><div><br></div><div>Assertion:</div><div><br></div><div>...</div><div>&lt;saml2:AttributeStatement&gt;</div><div>    &lt;saml2:Attribute</div><div>        Name=&quot;<a href="https://www.example.org/attributes/username">https://www.example.org/attributes/username</a>&quot; NameFormat=&quot;urn:oasis:names:tc:SAML:2.0:attrname-format:uri&quot;&gt;</div>
<div>        &lt;saml2:AttributeValue</div><div>            xmlns:xsi=&quot;<a href="http://www.w3.org/2001/XMLSchema-instance">http://www.w3.org/2001/XMLSchema-instance</a>&quot; xsi:type=&quot;xs:string&quot;&gt;(my value is printed here)&lt;/saml2:AttributeValue&gt;</div>
<div>    &lt;/saml2:Attribute&gt;</div><div>&lt;/saml2:AttributeStatement&gt;</div><div>...</div><div><br></div><div>attribute-map.xml</div><div><br></div><div>&lt;Attribute name=&quot;<a href="https://www.example.org/attributes/username">https://www.example.org/attributes/username</a>&quot; id=&quot;username&quot; /&gt;</div>
<div><br></div><div>I have also tried the following two formats, and neither work:</div><div><br></div><div>&lt;Attribute name=&quot;urn:oasis:names:tc:SAML:2.0:attrname-format:uri:<a href="https://www.example.org/attributes/username">https://www.example.org/attributes/username</a>&quot; id=&quot;username&quot; /&gt;</div>
<div>&lt;Attribute nameFormat=&quot;urn:oasis:names:tc:SAML:2.0:attrname-format:uri&quot; name=&quot;<a href="https://www.example.org/attributes/username">https://www.example.org/attributes/username</a>&quot; id=&quot;username&quot; /&gt;</div>
<div><br></div><div>I always end up with the following INFO message and nothing in the request for the service provider:</div><div><br></div><div>2013-07-19 16:58:53 INFO Shibboleth.AttributeExtractor.XML [5]: skipping unmapped SAML 2.0 Attribute with Name: <a href="https://www.example.org/attributes/username">https://www.example.org/attributes/username</a></div>
</div>