HTTP Basic Auth on Twisted-Klein server

Question

I am using Twisted-Klein as a server. Here is a simple example:

from klein import Klein


app = Klein()


@app.route('/health', methods=['GET'])
def health_check(request):
    return ''


@app.route('/query/<path:expression>', methods=['GET'])
def query(request, expression):
    return 'Expression: {0}'.format(expression)


if __name__ == '__main__':
    app.run(host='0.0.0.0', port=8000)

How can I add HTTP Basic Auth to query API endpoint? With Flask, this is simple: http://flask.pocoo.org/snippets/8/

But I fail to find any examples of how to do this on Twisted-Klein server.

Answer 1

Twisted itself has support for HTTP basic (and digest) authentication, factored as a resource wrapper that can be applied to any other resource.

Your klein example doesn't demonstrate it, but klein can (must, really) create a resource from your app in order to use Twisted's web server.

You can combine them something like:

import attr
from zope.interface import implementer
from twisted.cred.portal import IRealm
from twisted.internet.defer import succeed
from twisted.cred.portal import Portal
from twisted.web.resource import IResource
from twisted.web.guard import HTTPAuthSessionWrapper, BasicCredentialFactory
from klein import Klein

app = Klein()
# ... define your klein app

@implementer(IRealm)
@attr.s
class TrivialRealm(object):
    resource = attr.ib()

    def requestAvatar(self, avatarId, mind, *interfaces):
        # You could have some more complicated logic here, but ...
        return succeed((IResource, self.resource, lambda: None))

def resource():
    realm = TrivialRealm(resource=app.resource())
    portal = Portal(realm, [<some credentials checkers>])
    credentialFactory = BasicCredentialFactory(b"http auth realm")
    return HTTPAuthSessionWrapper(portal, [credentialFactory])

You can run this according to the klein docs for using twistd web.