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From Benoit Chesneau <>
Subject Re: userCtx extra information
Date Thu, 30 Aug 2012 19:09:39 GMT
On Thu, Aug 30, 2012 at 8:38 PM, Wendall Cada <> wrote:
> Jim,
> This is a very well thought out response. I believe is correct. In the
> current state, _users is unusable for anything other than 1. I don't even
> bother with that since I have to create an app layer to actually manage
> permissions, so I just don't expose it externally and run admin party and
> use ssh tunneling for sync (mostly because this was setup long before
> 1.2.0).
> Really the situation with admin or user as the only roles is bad. I have
> multiple roles. Where admin users are at the top of the food chain, but
> there are users with special permissions who can create regular users, or
> modify specific parts of the documents. An example of this is a comments
> thread moderator. They need permissions to edit portions of a doc that
> doesn't belong to them. Is it proposed that I just make everyone an admin?
> How can this work for couchapps. Maybe I'm missing something, but I don't
> see that this can work at all.
> _users just doesn't make sense unless all of the app capabilities get ripped
> out and CouchDB just becomes a database and nothing more. Otherwise, some
> hybrid as Jim mentions needs to happen. There is no reason to think that
> every last bit of the _user doc needs to be cached or in the session. This
> should be able to be retrieved however and stored where it makes sense, with
> the users account data.

Like I said there are some features actually missing in couch that
would ease that. (partial updates and partial fetch). Of course a view
could be use to see only profile but that would be a hack.

And this is not only about being a db or something alternative. This
is more about security here. Even in the old world data for
authentication and profiles are generally separated. For a good
reason. This isn't generally the same person that have access to them.
 And personnaly I would see a profile linked to a user but not in the
same doc.

Also I'm pretty sure that the reason people are asking about
populating this userCtx is because they lack the possibility to query
internally the db. This can be changed.

- benoît

> Wendall
> On 08/30/2012 10:06 AM, Jim Klo wrote:
>> Been following this thread a bit, and thought there's a unique
>> characteristic of CouchDB here that's being overlooked that should allow us
>> to address this problem in potentially a unique way.
>> There's basically 2 camps (dare I say religions) here:
>> 1) Traditional DB folks CouchDB's _users is special an should be reserved
>> for "applications as clients" and that end users should be stored
>> differently and separately.  Most clients that connect to the db will some
>> application that will manage data access.  App logic will decide who gets to
>> read/write - not the user who is actually connecting to the DB; their the
>> conductor.
>> 2) App developers: Who just want an HTTP API to save user info, utilize
>> for authentication, session management, and access control - they don't want
>> to rebuild this for every app, and certainly aren't interested in having to
>> write an additional server-side tier to make this work securely. Real people
>> use apps, real people are the ones who actually have where with all to fill
>> out a form and place it into some storage area, read some bit of privileged
>> or non-privileged info, etc... they don't really give a rip about some
>> middle-man user who's logic decides if they have the right credentials to
>> access.
>> CouchDB is a unique product: It can act as both a HTTP application server
>> and an indexed document store. I can't think of another solution that does
>> this so elegantly. Because of this, I think _users should be treated
>> differently than a traditional DB that uses JDBC/Named Pipe/ODBC/pick your
>> db connectivity poison to access the DB. Ultimately, in both camps, users
>> are being used to restrict the level of access to documents.  CouchDB for
>> the most part allows simple apps to 'eliminate the middle tier', which is
>> what the traditional db camp is trying, i think, to argue is less secure,
>> and thus one needs to mimic the middle tier and use isolation of data to
>> protect that _users db. The reality the way the CouchDB user model, IMHO can
>> actually be more secure, because the same user who is connecting to the app
>> via web, can be the exact same user that reads/writes to the document
>> store... no more middle tier application with god like powers having to
>> mediate user permissions.
>> CouchDB, for the most part is very orthogonally designed.  Configuration /
>> Users / Replication / Document DB are all essentially stored/treated in the
>> same manner (or at least shares a common API) that is more or less
>> schema-less (config is a tad different in that it persists to an INI file).
>> The _users db should continue to follow the same schema-less design it has
>> been; documents to be used for authentication should need to follow nothing
>> more than a duck typed convention any extra data should just be treated as
>> noise to parts of the core app that don't need it. If you want to store
>> additional info in user document, go for it - authentication should just
>> ignore it - its not hurting anyone, really.
>> Those arguing about making the _users db holy by hiding it completely and
>> limiting what you can store in the object breaks the fantastic orthogonality
>> that CouchDB enjoys today.
>> My vote? Continue keeping CouchDB orthogonal, in fact make it even more
>> so! IMHO - I think being able to store additional data that can be retrieved
>> via userCtx would be good; however I think there should be a flag that is
>> used when querying to include the extra data,(like include_docs=true, but
>> maybe full_userCtx=true)?.  As an app developer - you shouldn't need access
>> to all of the users additional attributes for every request.  That is
>> potentially a lot of extra data (equates to memory use/etc) that would go
>> unused on probably 90% of the requests made.  The middle tier / traditional
>> db guys & gals are happy - they can still do their own thing through god and
>> demi-god apps and manage access via their middle-tier (god help them!); and
>> the CouchApp guys & gals can go on with their own thing and leverage built
>> in _users functionality within CouchDB and get them access to the additional
>> userCtx as needed in their list/show/etc functions (heck they are already
>> double-dipping on the appserver / db combo).
>> Cheers,
>> *
>> *
>> *
>> *Jim Klo*
>> Senior Software Engineer
>> Center for Software Engineering
>> SRI International
>> *
>> *
>> *
>> *
>> *
>> *
>> t.@nsomnac
>> *
>> *
>> *
>> On Aug 30, 2012, at 8:13 AM, Gabriel Mancini wrote:
>>> I think this can be flexible to offer some aditional information as
>>> optional feature in userCtx.
>>> and with possibility to create a design document with validation login
>>> and
>>> use this info to auth/reject the user.
>>> this way we can trigger an 403 http error. this is more "REST" approach i
>>> guess
>>> On Thu, Aug 30, 2012 at 9:14 AM, john.tiger <
>>> <>>wrote:
>>>> On 08/30/2012 05:28 AM, Robert Newson wrote:
>>>>> In CouchDB 1.2.0 mandatory filters have been added when accessing
>>>>> _users
>>>>> such that no user can see another users document. So, you can allow
>>>>> signup
>>>>> (jquery.couch.js includes such a function) safely.
>>>>> As for expanding the userCtx, it's not something we're rejecting out
>>>>> hand or to annoy you. The userCtx object is provided to allow
>>>>> authorization
>>>>> decisions and the CouchDB security model is that these decisions are
>>>>> made
>>>>> on the user's name and/or the user's roles. Any additional information
>>>>> in
>>>>> there could also be used for authorization purposes which would alter
>>>>> the
>>>>> security model. Now, that might not be a bad thing, but it's not
>>>>> something
>>>>> to be done lightly.
>>>>> Further, practical points to consider. The name and roles are needed
>>>>> often and so they are stored in an in-memory cache. The larger you make
>>>>> userCtx, the less caching will be possible and performance will suffer.
>>>>> If
>>>>> you then further consider a sharded CouchDB system (after the BigCouch
>>>>> merge) then the user information you need, on a cache miss, might be
>>>>> another machine.
>>>>> The _users db exists to provide authentication/authorization services
>>>>> to
>>>>> CouchDB, it's unfortunate that it's also a CouchDB database as well as
>>>>> this
>>>>> leads to misconceptions. Most RDBMS's use system databases to provide
>>>>> similar service and, likewise, don't expand those things for
>>>>> application
>>>>> use.
>>>> from a good practice standpoint, Robert and Benoit are correct.  from a
>>>> coding standpoint, maybe someone has a ready made example of a view that
>>>> shows a check for auth/auth then a query on the associated user doc.
>>>> Then
>>>> the reverse, a post that creates a user and the user doc from the one
>>>> form.
>>>> It's fairly simple stuff but would save time and effort for everyone who
>>>> is using something like this (many apps).   This "how-to" could go into
>>>> the
>>>> couch guide or simply a couch how-to or cookbook wiki, something Couch
>>>> needs.
>>>>> B.
>>>>> On 30 Aug 2012, at 12:06, Aliaksandr Barysiuk wrote:
>>>>> We have a simple form for user registration with standard fields:
>>>>> fname,
>>>>>> lname, email, avatar url, etc. We want to have some section on the
>>>>>> page
>>>>>> that shows some of these field after user successfully logged in
>>>>>> 'Logged in as $fname + #lname', show avatar). Nothing special. For
>>>>>> userCtx is perfect place to store such information, because logged
>>>>>> user
>>>>>> always have access to it (we don't need to make any additional call).
>>>>>> It's
>>>>>> simple. What is the reason to keep user information separately?
>>>>>> I have already discuss this question with R.Newson and i can't say
>>>>>> that
>>>>>> i'm satisfied with the answers. Of course to create new user (signup)
>>>>>> you
>>>>>> need to be an admin, but we cannot specify admin credential on the
>>>>>> client
>>>>>> because everyone can use them, right? Other option is to open _usersdb
>>>>>> for
>>>>>> reading and writing which is crazy and totally unacceptable. As a
>>>>>> result
>>>>>> now we use node.js with JSONP call that sent all user info to node
>>>>>> server
>>>>>> and there user entry is saved into _usersdb with admin credentials.
>>>>>> we
>>>>>> need to write own authorization logic and use Couchdb as usual storage
>>>>>> which may takes a lot of time. Signup, reset password functions -
>>>>>> usual
>>>>>> operations on every web site.
>>>>>> Conclusion: couchdb makes development of web apps very convinient.
>>>>>> user management is the important part of each web app and now we
>>>>>> to
>>>>>> use external system (node.js in our case). It would be great if
>>>>>> Couchdb can
>>>>>> handle it without any other service.
>>>>>> PS. Sorry for long posts. I have a lot of thoughts to write down)
>>>>>> Alex
>>>>>> On 30/08/12 12:56, Benoit Chesneau wrote:
>>>>>>> On Thu, Aug 30, 2012 at 8:22 AM, Aliaksandr Barysiuk
>>>>>>> < <>>
>>>>>>>> I don't understand your position. Now Couchdb user management
is in
>>>>>>>> rudimentary state. It even doesn't allow to create new user
>>>>>>>> (without
>>>>>>>> opening access to _users db or using external service). I
>>>>>>>> that
>>>>>>>> Couchdb developers bothers more about performance, scalability
>>>>>>>> But you
>>>>>>>> totally forgot about simple cases. I'm sure that a big percent
>>>>>>>> web
>>>>>>>> apps
>>>>>>>> use user management. So what is the problem to develop convenient
>>>>>>>> authentication/authorization system? It is normal to have
>>>>>>>> information
>>>>>>>> in users db.
>>>>>>> Well you can't put extra informations in the postgresql user
>>>>>>> database.
>>>>>>> The question is more why do you want such extra information in
>>>>>>> db?
>>>>>>> - Is this because you don't have access to couchdb internally
in your
>>>>>>> couchapps?
>>>>>>> - Because you need to be an admin to create a user? (ie lacking
of a
>>>>>>> permission to create a user for anyone)
>>>>>>> - other? (and why in this case)
>>>>>>> And it's also normal that people want to see this information
>>>>>>>> in session. Using roles for that just shows you that the
>>>>>>>> exists. And
>>>>>>>> it is not a solution 'fix this bug' since it provides easiest
way do
>>>>>>>> what
>>>>>>>> Couchdb doesnt' provide out-of-the-box. And even you fix
roles to
>>>>>>>> have
>>>>>>>> only
>>>>>>>> strings it is not a big deal to concatenate all my data and
put it
>>>>>>>> as
>>>>>>>> string
>>>>>>>> in a role. It just adds some extra work on parsing that.
>>>>>>> Everything is possible. But doing it the clean way is hard. I
>>>>>>> think
>>>>>>> that roles should be anything but roles. ie things to manage
>>>>>>> permissions.
>>>>>>> Conclusion: I don't want to reinvent the wheel and develop own
>>>>>>>> authentication/authorization mechanism. The existing works
>>>>>>>> except
>>>>>>>> 2
>>>>>>>> things:
>>>>>>>> - add extra info to _users and being able to see it in the
>>>>>>>> - add signup function to Session API
>>>>>>>> Why sending a user doc isn't enough?
>>>>>>> I'm sure these things make Couchdb better and easy to use for
>>>>>>>> commercial
>>>>>>>> development.
>>>>>>>> Alex
>>>>>>>> On 29/08/12 23:05, Benoit Chesneau wrote:
>>>>>>>>> On Wed, Aug 29, 2012 at 9:54 PM, Gabriel Mancini
>>>>>>>>> < <>>
>>>>>>>>> wrote:
>>>>>>>>>> but can be nice have sume enable/disable behaviour
for user. We
>>>>>>>>>> could
>>>>>>>>>> have anything once partial updates and fetch  will
be here. But
>>>>>>>>>> it's
>>>>>>>>>> not the
>>>>>>>>>> case right now :)
>>>>>>>>> - benoit
>>>>>>>>>> On Wed, Aug 29, 2012 at 4:39 PM, Benoit Chesneau
>>>>>>>>>> < <>>wrote:
>>>>>>>>>> On Wed, Aug 29, 2012 at 9:24 PM, Dave Cottlehuber<
>>>>>>>>>> <>>
>>>>>>>>>>> wrote:
>>>>>>>>>>>> On 29 August 2012 08:21, Benoit Chesneau<
>>>>>>>>>>>> <>>
>>>>>>>>>>>> wrote:
>>>>>>>>>>>>> On Tuesday, August 28, 2012, Aliaksandr
Barysiuk wrote:
>>>>>>>>>>>>> Hello,
>>>>>>>>>>>>>> We store some extra information in
_users db and now we are
>>>>>>>>>>>>>> looking a
>>>>>>>>>>>>> way
>>>>>>>>>>>> to populate session.userCtx with these extra
values. Is it
>>>>>>>>>>>> possible
>>>>>>>>>>>>>> at
>>>>>>>>>>>>> all?
>>>>>>>>>>>> Thank you
>>>>>>>>>>>>>> Alex
>>>>>>>>>>>>>> user db isn't done for that. this
db exists to authenticate
>>>>>>>>>>>>> users and
>>>>>>>>>>>> only
>>>>>>>>>>>> that. You should better save the profiles
in another db. Also
>>>>>>>>>>>>> there is
>>>>>>>>>>>> no
>>>>>>>>>>>> such things like session in couchdb by itself.
>>>>>>>>>>>>> benoît
>>>>>>>>>>>> Any good reasons why we couldn't / shouldn't
support something
>>>>>>>>>>>> that
>>>>>>>>>>>> eases this pain? Putting in a second db simply
to store some
>>>>>>>>>>>> basic
>>>>>>>>>>>> profile info seems daft. And as others have
found, you can store
>>>>>>>>>>>> anything you like in roles.
>>>>>>>>>>> Well I think that storing anything in a role
is a bug. We
>>>>>>>>>>> shouldn't
>>>>>>>>>>> allow that and it should be fixed. Only a list
of strings is
>>>>>>>>>>> expected
>>>>>>>>>>> in the roles member. We should enforce that.
>>>>>>>>>>> For security reasons I don't think it's good
to have more data in
>>>>>>>>>>> the
>>>>>>>>>>> doc other than the login, roles, password and
possibly anything
>>>>>>>>>>> about
>>>>>>>>>>> permissions ( some would argue that the users
db shouldn't exist
>>>>>>>>>>> at
>>>>>>>>>>> all). You don't protect the same the access to
a user doc or a a
>>>>>>>>>>> profile doc. And the way it is designed right
now  prevent any
>>>>>>>>>>> use
>>>>>>>>>>> of
>>>>>>>>>>> this profile by others. Only the user or an admin
can have access
>>>>>>>>>>> to
>>>>>>>>>>> the doc. Which is good imo.
>>>>>>>>>>> - benoit
>>>>>>>>>>> --
>>>>>>>>>> Gabriel Mancini de Campos
>>>>>>>>>> Arquiteto de Soluções
>>>>>>>>>> +55 (11) 9449-1706
>>>>>>>>>> <>
>>>>>>>>>> São Paulo - SP - Brasil
>>> --
>>> Gabriel Mancini de Campos
>>> Arquiteto de Soluções
>>> +55 (11) 9449-1706
>>> <>
>>> São Paulo - SP - Brasil

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