[ckan-dev] integrating login between ckan and drupal

[Toby Dacre]

On 26 March 2013 14:34, David Read <david.read at hackneyworkshop.com> wrote:
> (cc'ing ckan-dev as others may be interested)
>
> At data.gov.uk, users can log in and the account is used across both
> Drupal and CKAN. We tried to have as few integration points between
> Drupal and CKAN as possible because it really adds to the complexity,
> but this was a key one to allow both the public and our hundreds of
> publisher users to interact seamlessly. I wrote more about this
> general Drupal/CKAN integration approach here:
> http://data.gov.uk/blog/integrating-ckan-and-drupal
>
> The design works nicely with CKAN 1.7.1 and Drupal 6, and I expect it
> to work fine with CKAN 2 and Drupal 7, but haven't tested it. It was
> not possible to do this functionality as a repoze.who plugin, and it
> man-handles repoze somewhat to get the desired outcome.
>
> Essentially, a user logs into Drupal as normal. Then when the user
> clicks on a CKAN page, a new piece of middleware sees the Drupal
> cookie in the request, and if it is valid then it tells CKAN's
> auth_tkt to log the user in (creating a CKAN cookie). CKAN needs its
> own User object, so if it doesn't exist then one is created. The
> user's name, email address and roles (permissions) are copied from the
> Drupal world to the CKAN User object. By setting the REMOTE_USER
> variable, the request continues, now logged in. Subsequent requests
> will be logged in by auth_tkt.

David,

Just to say that as part of the work I've been doing we will be
introducing an IAuthenticator Extension point that could also be used
here.

It essentially adds a few methods

identify_user() called in lib/base to identify the user
login() called during the login
logout() called during logout
abort() called when 401 pages get called

this could well work for this too.  It is currently experimental and
being used in saml2 authentication for one of our clients.  It may
well be in 2.1 but will not be in 2.0


>
> When checking the Drupal cookie, it checks it is for the correct
> hostname and then makes a call to a Drupal XMLRPC API (that was put
> together by our Drupal team and I don't know anything more) with the
> session ID: get_user_id_from_session_id(). From the Drupal "user ID"
> (node ID) we then ask Drupal get_user_properties() to get name, roles
> etc.
>
> Logging out of Drupal causes the cookie checking to fail and it logs
> out out of CKAN too.
>
> There are a few caveats to the system as it stands:
> a) when roles are given to a user in the Drupal world, the CKAN user
> needs to relogin to receive them. We only use it for sysadmin role
> (others are pure-CKAN roles), so that is not really an issue for us.
> b) https is not covered yet, but shouldn't be difficult
> c) CKAN doesn't create the user object until that user clicks on an
> CKAN page. This may not happen before an admin tries to give them CKAN
> permissions, which causes problems. Currently we have a warning
> message, but this could be solved with a bit more work.
>
> There are several data.gov.uk-specific assumptions in the code: the
> names of the roles we are interested in, users copied from Drupal are
> called user_d<number>. And of course the Drupal and CKAN sites are on
> the same hostname to share the cookies.
>
> The code is here:
> https://github.com/datagovuk/ckanext-dgu/blob/master/ckanext/dgu/authentication/drupal_auth.py
>
> As far as configuration goes, in our ckan .ini we set the values for:
> dgu.xmlrpc_username
> dgu.xmlrpc_password
> dgu.xmlrpc_domain
>
> and add 'dgu_drupal_auth' to ckan.plugins
>
> You can see in our plugin.py how to create the DrupalAuthPlugin to
> allow the middleware to be inserted into the request handling stack:
> https://github.com/datagovuk/ckanext-dgu/blob/master/ckanext/dgu/plugin.py
>
> We also added a repoze.who plugin to ensure that 401 'not allowed'
> requests sends the user to a custom 'not_authorized' web page, rather
> than the CKAN log-in form. To achieve that we added the plugin in
> who.ini:
>
> [plugin:dgu_auth_tkt]
> use = ckanext.dgu.authentication.auth_tkt:make_plugin
>
> In [plugin:friendlyform] and [plugin:openid] sections:
> rememberer_name = dgu_auth_tkt
>
> and in [identifiers]:
>     dgu_auth_tkt
> instead of
>     auth_tkt
>
> David
>
> On 26 March 2013 10:54, Irina Bolychevsky <irina.bolychevsky at okfn.org> wrote:
>> Hey David,
>>
>> Hope you're well. We were wondering if you have any documentation on how you
>> guys set up the shared login for the drupal and ckan parts of data.gov.uk
>> (or, how is this actually configured?).
>>
>> If not, any chance we can pick your brain on this? A post somewhere would
>> likely be popular!
>>
>> Cheers,
>> Ira
>>
>> --
>>
>> Irina Bolychevsky
>> CKAN Product Owner
>>
>> The Open Knowledge Foundation (http://www.okfn.org)
>>
>> More information on CKAN: http://ckan.org/
>>
>> Follow me on Twitter: http://twitter.com/shevski
>
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