avoid duplicating ldaptor code in LDAPServerWithUPNBind

[graingert]

Contributor Checklist:

• I have updated the release notes at docs/source/NEWS.rst
• I have updated the automated tests.
• All tests pass on your local dev environment. See CONTRIBUTING.rst.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.35%. Comparing base (c0bdfda) to head (e42ede9).
⚠️ Report is 217 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #161   +/-   ##
=======================================
  Coverage   93.35%   93.35%           
=======================================
  Files          72       72           
  Lines        9914     9914           
  Branches      972      972           
=======================================
  Hits         9255     9255           
  Misses        537      537           
  Partials      122      122           

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[adiroiban]

Thanks for the cleanup.
@graingert let us know when you think this is ready for review :)

[graingert]

@adiroiban I think it's ready to go

[adiroiban]

Maybe something like this

Suggested change

	def _request():
	if not (b"@" in request.dn and b"," not in request.dn):
	defer.returnValue(request)
	def _resolveUPNBindDN():
	"""
	See if we have an MS UPN style BIND DN request and resolve it to the
	actual LDAP BindDN.
	UPN bind is in the form of User.Name@ad.example.tld
	"""
	if b"@" not in request.dn or b"," in request.dn:
	# This is not an UPN bind request.
	defer.returnValue(request)

[adiroiban]

Suggested change

	# This might be an UPN request.
	# The the LDAP DN associated with the UPN request.

[adiroiban]

Suggested change

	if len(results) != 1:
	defer.returnValue(request)
	if len(results) != 1:
	# We could not find an exact UPN match so we go with the
	# requested Bind DN.
	defer.returnValue(request)

[adiroiban]

Thanks for the cleanup.

Please see my comments.

Even thou I wrote this code a few months ago, I feel that it needs more documentation.
With the current version, at the first read it was hard to understand what is going on there and why we have all that logic.