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Interesting... those portals could be on different Realms too. It would also allow more than one checker to be tried per interface, which would allow (say) a credentials.IUsernamePassword to be tried against different checkers.</div>
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Peter.</div>
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On Sun, Jan 13, 2013, at 14:08, Itamar Turner-Trauring wrote:</div>
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It's possible that in some of the cases discussed above, what you want is a custom <span style="font-style: italic">Portal</span>. For example, if you want to try a sequence of logins, and choose the first that succeeds:</div>
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<span style="font-family: "courier new"," monospace"; ">class MultiPortal(object):</span></div>
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<span style="font-family: "courier new"," monospace"; "> def __init__(self, portals):</span></div>
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<span style="font-family: "courier new"," monospace"; "> self.portals = portals</span></div>
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<span style="font-family: "courier new"," monospace"; "> @inlineCallbacks</span></div>
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<span style="font-family: "courier new"," monospace"; "> def login(self, *args, **kwargs):</span></div>
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<span style="font-family: "courier new"," monospace"; "> for portal in self.portals:</span></div>
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<span style="font-family: "courier new"," monospace"; "> try:</span></div>
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<span style="font-family: "courier new"," monospace"; "> return portal.login(*args, **kwargs)</span></div>
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<span style="font-family: "courier new"," monospace"; "> except:</span></div>
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<span style="font-family: "courier new"," monospace"; "> continue</span></div>
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<span style="font-family: "courier new"," monospace"; "> # Ran out of portals, failed to login:</span></div>
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<span style="font-family: "courier new"," monospace"; "> raise Unauthorized()</span></div>
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Or, let's say you're writing a backend that is a combination checker and realm, where separating that two doesn't make sense. E.g. a backend for a POP3 server that is a proxy to another POP3 server. In this case there's no point in writing separate checker and realm, just write a new Portal:</div>
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<span style="font-family: "courier new"," monospace"; ">class POP3ProxyPortal(object):</span></div>
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<span style="font-family: "courier new"," monospace"; "> def __init__(self, endpoint):</span></div>
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<span style="font-family: "courier new"," monospace"; "> self.endpoint = endpoint</span></div>
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<span style="font-family: "courier new"," monospace"; "> @defer.inlineCallbacks</span></div>
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<span style="font-family: "courier new"," monospace"; "> def login(self, credentials, mind, *interfaces):</span><span style="font-family:'courier new',monospace"> </span></div>
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<span style="font-family: "courier new"," monospace"; "> pop3client = yield self.endpoint.connect(POP3ClientFactory())</span></div>
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<span style="font-family: "courier new"," monospace"; "> yield pop3client.login(credentials.username, credentials.password)</span></div>
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<span style="font-family: "courier new"," monospace"; "> defer.returnValue((IMailbox, MailboxProxy(pop3client), pop3client.quit))</span></div>
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<br class="me69157Apple-interchange-newline" />
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-- <br />
Itamar Turner-Trauring, Future Foundries LLC<br />
<a href="http://futurefoundries.com/" target="_blank">http://futurefoundries.com/</a> — Twisted consulting, training and support.</div>
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