Authentication Service

Need to integrate user logins to new authentication service? e.g. using LDAP, OAuth, Openid, Mongo, or ZODB to source user credentials.

There are 4 facilities of which 2 are optional:

  • User provider, required
  • User resolver, required
  • Password changer, optional
  • User searcher, optional


You can find an “in-memory” user provider in examples/

User provider

A Principal (User) must have at least 3 attributes:

  • user.uri, which must be resolvable to the User model
  • user.login, which is identifier such as email
  •, human readable user name

The Provider class provides 2 methods:

  • authenticate, which takes a mapping {‘login’:’user’, ‘password’:’pw’}
  • get_principal_bylogin, which takes a login string and returns User

You register a Provider by calling ptah.register_auth_provider and provide a uri scheme and instance.

User resolver

Resolvers in Ptah are the way we indirect lookup between components. For instance, instead of storing the primary key of the user for say, the ptah.cms.node.Owner field; we make that a string and store a URI. URIs can be resolved into a object.

This code registeres a function which returns a object given a URI:

@ptah.register_uri_resolver('user+crowd', 'Crowd principal resolver')
def getPrincipal(uri):
    return User.get(uri)

Any uri prefixed with ‘user+crowd’ will be sent to this function, getPrincipal. For instance, uri.resolve(‘user+crowd:bob’) would be sent to getPrincipal to return a Principal with that uri.

Password changer

A function which is responsible for changing a user’s password. An example:

ptah.pwd_tool.register_password_changer('user+crowd', change_pw)

Password changer is optional.

Principal searcher

A function which accepts a string and returns a iterator. This is registered with URI scheme and function:

import ptah
ptah.register_principal_searcher('user+crowd', search)


There is another authentication service, ptah+auth which provides a sole superuser Principal. The name is superuser. It is a special Principal. You can not login with this Prinipcal. It is useful for integration tests.