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I don't understand what the "username" field length has to do with it.
And I think that's also the problem with Clay's original post:
Do you want to authenticate against email or also change the User model?
What if I want to authenticate against email but still have a username ("nick")?
Another setting?
An auth backend that checks against the email address (which is
already in the User model just like username) _is_ simple.
Rapid and simple would be to _ship_ such a backend in contrib.auth.backends.
Then it would really just be a single setting (AUTHENTICATION_BACKENDS
= ('django.contrib.auth.backends.EmailBackend',)).
The only thing left would be the label on the login template in my
naive understanding. (another one-liner I believe)
So I agree it would be nice and useful, but where's the monkeypatching.
If you want to authenticate against email _and_ take the "username"
out of the model, it's that second part that's the problem. That's
where I believe a set of settings and conditions is a kneejerk
workaround.
Cheers,
Danny
if settings.AUTH_EMAIL_AUTHENTICATION:
Should these things really take five years? What happened to pragmatic?
It's the "required" of username that's the problem if you don't want a
username at all when authenticating against email.
It would have to be not required and check required fields in clean()
where the backend could be asked what's really required.
And there's Mr. Schema Migration again...
Cheers,
Danny
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It's the "required" of username that's the problem if you don't want a
username at all when authenticating against email.
It would have to be not required and check required fields in clean()
where the backend could be asked what's really required.
And there's Mr. Schema Migration again...
I'm sorry, that completely mis-characterises the situation. Lots of
people want this, but every single time this has been brought up since
I started using django (1.0), a core dev or BFDL has explicitly ruled
it out, saying "we cannot do this, requires schema migration, we'll
look at it for the next version".
At this point, the discussion is stopped. Once a proposal has the
smack down from a BFDL, what point is there trying to get it
integrated?
The next version comes, has it been addressed? No. Will it be
addressed in 1.4? No. Will it be addressed in 1.5? Possibly, but I
doubt it.
At $JOB we've given up waiting for some trivial changes, and have
simply patched django to not have these silly, arbitrary and incorrect
requirements¹ on email address and username.
We live in the real world, we have to be able to handle email
addresses that are of a valid length. We cannot tell a paying customer
"I'm sorry, your email address is too long, do you have one under 75
characters?"
It's a really invalid position to take, knowing something is broken
and incorrect, but not fixing it because 'change is hard'.
Cheers
Tom
¹ Here is my list of things that are broken with d.c.auth:
1) Length and character restrictions on username field. If I want to
use emails address as usernames, or usernames with spaces, the choices
made at lawrence.com 3+ years ago should not restrict me.
2) Email address fields must be large enough to hold valid email
addresses - that's 254 characters.
> Who's talking about a migration? I'm asking for something that will work
> for *new* installations; existing installations can continue
> authenticating against usernames for all I care :)
>
> Moreover, I'm thoroughly frustrated by the fact that developers *do*
> bring working solutions to the table (in the form of patches in trac),
> but the core developers won't integrate them, either because it's not
> the right time (usually right before a release), because the patch isn't
> general enough, or because the patch doesn't meet some absurdly high bar
> of quality. I understand that they have a commitment to backwards
> compatibility and that accepting a mediocre patch could mean maintaining
> it for life, but I like to think that—with a framework that purports to
> be "pragmatic"—there are pragmatic solutions to these problems—and not,
> "sorry, it's not perfect, it can't go in."
What you are really saying is this: being pragmatic means that we
prioritise *your* immediate need above the need to keep the code and the
docs maintainable, and above the need to maintain compatibility with
existing installations.
There are a million-and-one hacks we would add if we took that approach,
and Django would have a million-and-one more bugs, or possibly much
worse - if you add just 10 boolean switches like the one you suggested
in an earlier email, you've got over 1000 combinations to test and
debug. The only way to avoid that in a framework like Django is well
defined APIs for components. No-one has brought such a thing to the
table and seen it through, that's why it hasn't come in.
I believe that all the problems you have can be solved already:
- you can write your own authentication backend to authenticate
by email
- you can write your own login and account creation views
- you can even override admin views by inserting items into
urls.py
Yes, these are all more-or-less hacky. And they have problems. For
instance, what if you have two accounts with the same email address? (I
have that in some of my Django projects, BTW). The current code allows
it, so we can't change anything that would make it impossible, at either
the DB level or the Python level. This is the kind of issue that means
you can't just use the existing models.
A full and correct solution that didn't introduce dozens of new bugs is
quite hard - and I'm talking about just the code required to fix this
one feature for you, without doing anything more generally useful.
That is why we're not going to put hacks like this in core - we would
have to support these hacks for at least 3 versions if we did. We are
interested in *removing* existing hacks from our code base, and this is
vital if Django is going to see increases in features and functionality.
We are not interested in adding more hacks.
We also will refuse to litter our documentation with things like: "if
you've got this setting, it does this, otherwise you get this other
behaviour, and you've got to watch out for all these bugs because this
is a gross hack".
> The GSoC page
> (https://code.djangoproject.com/wiki/SummerOfCode2011#Enhancedauth.user)
> is a frustrating read. It goes on and on about how hard the problem is
> and how wrong your solution is, but doesn't provide any detail as to why
> it's hard or why it's wrong.
It does provide detail - it gives a list of issues you have to consider,
and tells you where to search for the other issues.
Some examples from a quick Google groups search for "auth User":
These provide a lot of detail.
> Ticket #3011 was rejected without much of a
> reason. HM asked for an explanation both in the ticket itself and on
> django-dev; no explanation was ever given.
I don't know what thread you are talking about. Hanne Moa brings up the
subject here and gets two replies from Russell:
Regards,
Luke
--
"I imagine bugs and girls have a dim suspicion that nature played a
cruel trick on them, but they lack the intelligence to really
comprehend the magnitude of it." (Calvin and Hobbes)
Luke Plant || http://lukeplant.me.uk/
Even with these things, you are limited by the length of the username
field, the length of the email field, and the arbitrary restrictions
on what consists a username.
The length restrictions could be fixed straight away, and a note added
to the next relnotes informing users that the field has changed in
size. If they do not update their DB structure, then depending on the
database used, they will either get errors when a field value is
longer than the old limit, or silent truncation.
It's not ideal, but it doesn't cause any major problems for anyone who
reads the relnotes, and it will have to be done at some point anyway.
Even if Django did have schema migrations, the same behaviour would
occur for anyone who read the relnotes and did not apply the
migration, and many users with 'interesting' DB structures would not
be able to simply apply schema migrations either, so they would have
to do it by hand anyway.
It feels to me that only fear of change and how to manage that change
is what is stopping d.c.auth from being fixed.
>
> Yes, these are all more-or-less hacky. And they have problems. For
> instance, what if you have two accounts with the same email address? (I
> have that in some of my Django projects, BTW). The current code allows
> it, so we can't change anything that would make it impossible, at either
> the DB level or the Python level. This is the kind of issue that means
> you can't just use the existing models.
>
Good for you! I don't see that as an issue. If you are using email
address as a unique name for identifying a user, we already have a
column for that, it's called username, and it has some of the right
semantics (unique, indexed field). It is the arbitrary length and
content restrictions that stop this from happening right now.
I don't see why wanting to use email address as the unique identifier
and username for a user requires any modification to the database,
apart from (as I keep repeating) removing the arbitrary length and
content restrictions on username.
> A full and correct solution that didn't introduce dozens of new bugs is
> quite hard - and I'm talking about just the code required to fix this
> one feature for you, without doing anything more generally useful.
>
> That is why we're not going to put hacks like this in core - we would
> have to support these hacks for at least 3 versions if we did. We are
> interested in *removing* existing hacks from our code base, and this is
> vital if Django is going to see increases in features and functionality.
> We are not interested in adding more hacks.
>
> We also will refuse to litter our documentation with things like: "if
> you've got this setting, it does this, otherwise you get this other
> behaviour, and you've got to watch out for all these bugs because this
> is a gross hack".
>
I agree with this 100%. d.c.auth needs to be fixed, not have many
different settings that alter it's behaviour.
Cheers
Tom
>> Yes, since no one needs it. Okay no one isn't true, but no one (for true
>> this time) who needed it stepped up and said "I'll implement it and see that
>> it ends up in trunk"
>>
>
> I'm sorry, that completely mis-characterises the situation. Lots of
> people want this, but every single time this has been brought up since
> I started using django (1.0), a core dev or BFDL has explicitly ruled
> it out, saying "we cannot do this, requires schema migration, we'll
> look at it for the next version".
This is not true. There have been times when we have said we cannot
consider it right now, and that a solid proposal should be brought up at
the calls for proposals for 1.1/1.2/1.3 etc., or at other times when the
core developers can look at it.
And every time, the proposal has either been missing or simply not been
adequate - for example, the GSoC 2010 and 2011 proposals regarding this.
Russell gave detailed feedback on why these solutions were not adequate
[1], and at other times has provided feedback on possible strategies
[2]. And the people who went away to work on the problem have gone
silent or admitted defeat. One presumes they fixed their immediate
problem in a way that would not be a general solution, and moved on, and
that is perfectly understandable. A adequate solution to this is very
hard, and probably requires solving several other big problems first
(like at least one of lazy foreign keys/virtual models/database migrations).
It isn't, however, impossible. Our definition of 'need' is that someone
is sufficiently motivated to overcome the obstacles, and contribute a
solution that works for other people as well as themselves.
Regards,
Luke
--
Luke Plant || http://lukeplant.me.uk/
I disagree. There are small problems with the User model that have not
been fixed. Every proposal you've listed does not address these
issues, but instead looks to find ways of replacing the base user
object, which is a complex and difficult project.
There is a reason why these are the proposals. Every time someone
proposes fixing these minor bugs, the cry from on high is that
instead, d.c.auth will be overhauled to allow for more customization
by the project, immediately increasing the scope and complexity. But
this fabled d.c.auth2 never appears.
In fact, your reply alludes to this. We're talking about why a field
is too short to contain valid values, and you suggest that the
solution inevitably will involve "lazy foreign keys/virtual
models/database migrations" - it's changing one line, and adding a
comment to relnotes!
We may have to agree to disagree on how easy some of these things are to fix.
Lets look at one isolated aspect. The User email field in d.c.auth is
too short. Emails can be up to 248 characters long, and d.c.auth only
allows 75.
Clearly, this is a bug, is wrong and should be fixed. How can we fix it?
We can alter the length of the field in the model definition. What
problems does this bring?
Users who do not manually update their database will not be able to
store longer length emails, and will get 'strange effects' when they
try - either silent truncation, or database integrity errors. How can
we mitigate this for users who refuse to update?
Provide a compat shim that resets the email length to that in 1.3, and
immediately mark it PendingDeprecation. Users who read the relnotes
and don't want to change their DB can use the shim, and have a clear
expectation of when they must have updated their database.
I still think these bug fixes are paralysed by a fear of change, and a
desire to engineer a solution that is every thing to every man. Lets
just fix these glaring bugs…
Cheers
Tom
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The latest RFC[1] actually specifies this as 256 *octets* with max of
64 octets for the local part and 255 octets for the domain name. So
248 *characters* would actually be incorrect and all the tedious and
error prone fixing of every Django instance would just get wasted.
I don't really think this is a "fear of change" case. It's more of "we
don't want to have to fix this again" thing.
[1]: http://tools.ietf.org/html/rfc5321#section-4.5.3.1.1
--
Łukasz Rekucki
Sorry, 248 was a typo. If you look at my earlier reply in this thread,
I had correctly stated the maximum length of an email address as 254
*characters*.
If you check two paragraphs later in the RFC that you linked to, you
would see confirmation of this:
http://tools.ietf.org/html/rfc5321#section-4.5.3.1.3
You may also need to remind yourself what the definition of a path is.
As all email headers are either 7 or 8 bit encodings, describing 254
octets as 254 characters is perfectly valid.
None of this changes that django keeps shipping with bad defaults.
This was brought up for 1.1, 1.2, 1.3 and now 1.4.
Cheers
Tom
And RFC 3696 originally claimed it's 320. Even after errata it still
says 256, but you are right that 254 is probably more correct.
>
> As all email headers are either 7 or 8 bit encodings, describing 254
> octets as 254 characters is perfectly valid.
UTF-8 is an 8-bit encoding that doesn't map octets to characters, so
no. But that's not really the point I wanted to make.
My point is that this kind of things change and we should have tools
to deal with that. We already have the exact same problem with IPv6
and contrib.comments, it's just people didn't noticed it yet as much.
Doing this by hand every time isn't very effective. Django needs
schema migrations.
As for the "design page" that Joe mentioned, the GSOC description is a
good start:
https://code.djangoproject.com/wiki/SummerOfCode2012#Enhancedauth.user
--
Łukasz Rekucki
On 9 March 2012 21:10, Tom Evans <teva...@googlemail.com> wrote:
> 2012/3/9 Łukasz Rekucki <lrek...@gmail.com>:
>> On 9 March 2012 17:46, Tom Evans <teva...@googlemail.com> wrote:
My point is that this kind of things change and we should have tools
to deal with that. We already have the exact same problem with IPv6
and contrib.comments, it's just people didn't noticed it yet as much.
Doing this by hand every time isn't very effective. Django needs
schema migrations.
> While, I generally agree with the current approach, especially this close to release. I'm going to play devil's advocate for a bit.
>
> Schema migrations have been talked about for quite a while. There are at least 3 external implementations I know of: South, nashvegas, and django-evolution. I'm unsure of the status of django-evolution, but the other two appear quite active.
Django Evolution isn't dead. It's sleeping. It's got lovely plumage, you know... :-)
Seriously -- I stopped working on Evolution several years ago. I formally handed over the project to Christian Hammond almost 2 years ago, but this has been mostly for maintenance purposes, rather than active development. For the benefit of posterity, I blogged about the reasons [1].
[1] http://cecinestpasun.com/entries/end-my-evolution/
> A concern in my mind is that all three go off and do things totally different ways, and the migration path to a common standard is more difficult.
>
> I love the idea of not choosing a tool to make the migrations, but instead add to the ability to execute migrations. Now comes the conversation of what that means. I would love to try to get this in to Django 1.5.
A lot of this conversation has already happened, and it has core team approval. Most of these discussions were elaborated in last year's aborted GSoC 2011 project; search the django-dev archives from this time last year to see the details of what was being proposed.
The short version:
* Add a db.backends module to provide an abstract interface to migration primitives (add column, add index, rename column, rename table, and so on).
* Add a contrib app that performs the high level accounting of "has migration X been applied", and management commands to "apply all outstanding migrations"
* Provide an API that allows end users to define raw-SQL migrations, or native Python migrations using the backend primitives.
* Leave the hard task of determining dependencies, introspection of database models and so on to the toolset contributed by the broader community.
Under this approach, South would still need to exist, but it would be a tool leveraging the primitives exposed by Django itself. Over time, more features from South (and any other migration support projects that emerge) could be merged into trunk as the community converged on a feature set or an implementation.
One of the big issues that needs to be addressed is testing -- we need to have the infrastructure that allows us to check that migrations have been applied. Arthur Koziel's AppRefactor (a GSoC 2010 project) has some analogous testing problems, so getting migrations into trunk may be dependent on getting the App Refactor into trunk as well. The good news is that the App Refactor also forms the likely stub for fixing the auth.User problem -- but that's a separate discussion.
> Now on to the meat of what I really want:
> Is there something along the lines of the GNOME design group for Django? (example: https://live.gnome.org/Design/Apps/Web). I'd love a template for the wiki or even better an app to discuss these things. If only we had some web developers ;) So, is there a sanctioned tool already out there? Or should I start building up a page on the wiki for this? I think most things become much easier once one gets a blueprint and requirements for what the design goals are. Especially if one can get an initial "this looks acceptable" by a core committer before "wasting one's time" because the requirements weren't even correct.
There are some historical examples where we've used the wiki to elaborate on an idea as a precursor to getting a feature into core.
https://code.djangoproject.com/wiki/SessionMessages
https://code.djangoproject.com/wiki/ClassBasedViews
https://code.djangoproject.com/wiki/LoggingProposal
https://code.djangoproject.com/wiki/ReplacingGetAbsoluteUrl
(The first two are probably the best examples to follow)
There is a wiki page which has been used in the past to discuss schema evolution (which it looks like you've found); however, it's wandered a little off the reservation. There's probably some good material in there still, but if someone is looking at this, it would benefit from some manicuring, and probably a complete reboot:
https://code.djangoproject.com/wiki/SchemaEvolution
There isn't a specific wiki template that we require -- this is mostly because every project has slightly different requirements. However, the broad format is fairly common:
* describe the problem
* describe any specific design constraints
* describe the possible approaches and their benefits/limitations
* list any prior art
* list any draft implementations
If you want to work on this, I can guarantee that you would have as much support as I and Andrew Godwin (South maintainer and Django core developer) can muster. This is one of the big ticket items missing from Django's core, and I'd *love* to see someone take a serious swing at addressing it. As with every big feature that is "missing" from Django (be it migrations, auth.User problems, or anything else), the issue is almost always finding someone who is willing to do the work -- not just for a day or two, but to actively drive a project for several months.
Yours,
Russ Magee %-)
What you are really saying is this: being pragmatic means that weprioritise *your* immediate need above the need to keep the code and the
docs maintainable, and above the need to maintain compatibility with
existing installations.
There are a million-and-one hacks we would add if we took that approach,
and Django would have a million-and-one more bugs, or possibly much
worse - if you add just 10 boolean switches like the one you suggested
in an earlier email, you've got over 1000 combinations to test and
debug.
I believe that all the problems you have can be solved already:
- you can write your own authentication backend to authenticate
by email
- you can write your own login and account creation views
- you can even override admin views by inserting items into
urls.py
Yes, these are all more-or-less hacky. And they have problems. For
instance, what if you have two accounts with the same email address? (I
have that in some of my Django projects, BTW). The current code allows
it, so we can't change anything that would make it impossible, at either
the DB level or the Python level. This is the kind of issue that means
you can't just use the existing models.
A full and correct solution that didn't introduce dozens of new bugs is
quite hard - and I'm talking about just the code required to fix this
one feature for you, without doing anything more generally useful.
That is why we're not going to put hacks like this in core - we would
have to support these hacks for at least 3 versions if we did. We are
interested in *removing* existing hacks from our code base, and this is
vital if Django is going to see increases in features and functionality.
We are not interested in adding more hacks.
Some examples from a quick Google groups search for "auth User":
http://goo.gl/swTpr
http://goo.gl/fFlKh
> Ticket #3011 was rejected without much of aI don't know what thread you are talking about. Hanne Moa brings up the
> reason. HM asked for an explanation both in the ticket itself and on
> django-dev; no explanation was ever given.
subject here and gets two replies from Russell:
http://goo.gl/7p1JN
> The GSoC pageIt does provide detail - it gives a list of issues you have to consider,
> (https://code.djangoproject.com/wiki/SummerOfCode2011#Enhancedauth.user)
> is a frustrating read. It goes on and on about how hard the problem is
> and how wrong your solution is, but doesn't provide any detail as to why
> it's hard or why it's wrong.
and tells you where to search for the other issues.
I've written such a pluggable User app. By default, the User model works as before. But I've also provided a User model (and forms, admin, backends, etc) implementation that removes the limitations of the User model noted above and allows for email authentication. It's still a bit rough around the edges, but it works, insofar that `manage.py createsuperuser` doesn't ask for a username, `manage.py changepassword` takes an email address, and I can login to the admin interface with my email address.
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Sure - that sounds like a reasonable addition to me. Open a documentation ticket, and we'll see if we can slip it in.
Yours,
Russ Magee %-)
> I started a new page off the old https://code.djangoproject.com/wiki/SchemaEvolution (https://code.djangoproject.com/wiki/SchemaEvolutionDesign). It's not complete at this point, I just did a brain dump of what I remembered hearing in the past. Sounds like I'm not TOO far off with my memory.
>
> Also, is the following the thread you are thinking of? http://groups.google.com/group/django-developers/browse_thread/thread/6239a63c9ad874b5/
That's the GSoC discussion I'm thinking of; it covers the db.backends part of the discussion. There is another post by Andrew from a little earlier that also includes the 'migration accounting' part of the problem:
http://groups.google.com/group/django-developers/browse_thread/thread/bac15726fa5e9662
> Also, Russell, I didn't know you were the one behind django-evolution. I may need to pick your brain at some point. I have a couple ideas I'd like input on, but I'm not quite ready yet. Now I wish I had tried harder to get to PyCon this year, but work was supposed to be quite hectic this week.
Unfortunately, I couldn't make it to PyCon this year. However, I'm more than happy to have my brain picked by someone who is volunteering to pitch in on schema migration.
Yours,
Russ Magee %-)
I've written such a pluggable User app. By default, the User model works as before. But I've also provided a User model (and forms, admin, backends, etc) implementation that removes the limitations of the User model noted above and allows for email authentication. It's still a bit rough around the edges, but it works, insofar that `manage.py createsuperuser` doesn't ask for a username, `manage.py changepassword` takes an email address, and I can login to the admin interface with my email address.Can you please post this code somewhere? I'd love to see it.
What you are really saying is this: being pragmatic means that weprioritise *your* immediate need above the need to keep the code and the
docs maintainable, and above the need to maintain compatibility with
existing installations.
I'm sorry I don't know if I like that. I hope I understand correctly
what you're doing, and that my criticism is seen as constructive.
This sells itself as "pluggable auth" but really only provides the
originally requested auth by email, and I don't see how it could go
from there, i.e. what else would be possible (in regards to auth).
Pulling username and email out of (Base)User and then bringing one or
both of them - and the logic of which to check - back in, is not
really a pluggable auth.
It's the mixing of profile and information relevant to authentication
(and authorization - is_staff?) that's another problem of the existing
User model, and this is where this approach allows for dangerous
developments.
You've pulled those two out and said it's up to the chosen auth to
decide a) which to even include in the User model b) which is used to
authenticate and which is just "secondary" user (profile?)
information.
What about first_name and last_name? Why can't a pluggable auth dump
those from the User model? And certainly an "auth" should get to have
a say about "password".
And then... there's not much left anymore in that (Base)User model,
right... (GSoC: "reducing the user table to little more than an
identifying primary key")
Ok email auth problem solved. But now there's a simple way of
providing any User model I like, so first thing I'm going to do is to
bring in what I think the User should look like i.e. use the "auth" to
define what really is a "profile". And so will lots of projects. "The
User model needs a username for this app to work". "The User model
needs a timezone for this app to work". etc.
I'd like to see a later, "proper" auth.user that can undo that chaos.
Cheers,
Danny
I originally thought you intended a setting which let's the user
switch from the existing auth to an email auth with corresponding User
model.
As lame as that may be - at least a later, "proper" auth.user solution
would only have two known (shipped) auths to deal with.
Cheers,
Danny
And Django developer ought to be familiar how to do a schema migration for
this simple change, and if they fail to know instructions can be provided in
the release notes; there is NO need to have progress being stalled because
there is no built automated schema migration.
Why can we not just increase the length limit on the username field?, Why
can't we just throw a validation error if data entered is to long and the
schema has not been updated? I think the answer yes we can and easily.
just fix these glaring bugs�
Cheers
Tom
On March 15, 2012, at 11:24 , Daniel Sokolowski wrote:
> Tom makes a good point, but you can already store emails in the username, they are just limited to 30 characters or fewer. Lift this length restriction and I will be able to do everything I need without having to wait for contrib.auth2. In the 'I use django to make a living' world the solution doesn't have to be perfect just good enough. The talk of lazy foreign keys just so we can create contrib.auth2 just rubs me the wrong way, adds additional complexity, and I see no benefit of it over a UserProfile model or with model inheritance.
>
> And Django developer ought to be familiar how to do a schema migration for this simple change, and if they fail to know instructions can be provided in the release notes; there is NO need to have progress being stalled because there is no built automated schema migration.
>
> Why can we not just increase the length limit on the username field?, Why can't we just throw a validation error if data entered is to long and the schema has not been updated? I think the answer yes we can and easily.
Wouldn't increasing the length of the username field *also* incur a schema migration? After all, anyone who has spun up a Django site previous to the change would have a CHARACTER VARYING(30) (or a VARCHAR(30) or whatever the appropriate database-specific type is) in their database. So, we'd have a situation where Django would accept a 40 character email address, but then the database would truncate it or error out.
The argument that Django developers ought to know how to do the schema migrations themselves seems poor to me. I expect some don't, and it's certainly a bigger backwards incompatible change than the Django development community has traditionally been comfortable with.
Regards,
Luke
> just fix these glaring bugs…
1. We provide MySQL, Sqlite3, PostgreSQL instructions on how to do it - I
mean the actual commands to execute.
2. Catch the DB error and throw a form validation warning for those that
didn't.
Regards,
Luke
> just fix these glaring bugs�
On 03/15/2012 09:24 AM, Daniel Sokolowski wrote:
> Why can we not just increase the length limit on the username field?,
> Why can't we just throw a validation error if data entered is to long
> and the schema has not been updated? I think the answer yes we can and
> easily.
I don't mean to pick on you specifically, but to me this is an excellent
example of a casual assertion of something we can "easily" do that
doesn't hold up under real examination (for instance, if you tried to
write the patch to actually do it).
How do you propose to "throw a validation error" if "the schema has not
been updated"? How do we know whether it's been updated? Are you
proposing that Django should introspect the users database table every
time it starts up in order to check the length of the username field?
Where would you put this introspection check? Have you considered the
effects this would have on every user of contrib.auth (both those who do
and don't run the schema migration)? And the effect on Django
development (needing to run the tests with both an "old" and "new" table
to ensure that the backwards-compatibility handling is tested?)
Carl
Catching the database error won't work - some databases won't raise an
error, they'll just silently truncate the value, potentially leading to
all sorts of nasty data corruption problems and confusing bugs down the
road.
Carl
> Carl, I sincerely appreciate your feedback, however again it seems no answers are given except more questions and considerations to consider. Why is it so unreasonable that we expect the end developer to be able to manually adjust their schemas, it's part of an upgrade process and it's been done in the past labelled backwards incompatible changes due to bugs or security, perhaps 30 character limitation ought to be considered a design bug - tomorrow I'll do an R&D day and see the feasibility of a solution.
>
I don't think Carl's point was to provide answers; his point was to explain why the proposal isn't a very good one. He doesn't have to propose an alternative to establish that a proposal doesn't work.
Most of Django's backwards incompatible changes are corner cases that most end developers never actually encounter. The only exception I can think of to this is the CSRF changes to AJAX requests in Django 1.3. This change, on the other hand, would affect basically every single Django installation; this is much more widespread than past Django releases.
Regards,
Luke
> -----Original Message----- From: Carl Meyer
> Sent: Thursday, March 15, 2012 12:49 PM
> To: django-d...@googlegroups.com
> Subject: Re: authentication by email
>
The issue here is that django auth is limited, and restrictive and needs
hacks to make it use emails as usernames, we can agree on that yes? We can
also agree that contrib.auth2 with LFK is a complex undertaking far into the
future?. Can we also agree that the 30 character limitation on the username
ought to be increased?
-----Original Message-----
From: Luke Sneeringer
I'm sorry I don't know if I like that. I hope I understand correctly
what you're doing, and that my criticism is seen as constructive.
This sells itself as "pluggable auth" but really only provides the
originally requested auth by email, and I don't see how it could go
from there, i.e. what else would be possible (in regards to auth).
Pulling username and email out of (Base)User and then bringing one or
both of them - and the logic of which to check - back in, is not
really a pluggable auth.
It's the mixing of profile and information relevant to authentication
(and authorization - is_staff?) that's another problem of the existing
User model, and this is where this approach allows for dangerous
developments.
What about first_name and last_name? Why can't a pluggable auth dump
those from the User model? And certainly an "auth" should get to have
a say about "password".
And then... there's not much left anymore in that (Base)User model,
right... (GSoC: "reducing the user table to little more than an
identifying primary key")
Ok email auth problem solved. But now there's a simple way of
providing any User model I like, so first thing I'm going to do is to
bring in what I think the User should look like i.e. use the "auth" to
define what really is a "profile". And so will lots of projects. "The
User model needs a username for this app to work". "The User model
needs a timezone for this app to work". etc.
I'd like to see a later, "proper" auth.user that can undo that chaos.
The issue here is that django auth is limited, and restrictive and needs hacks to make it use emails as usernames, we can agree on that yes?
We can also agree that contrib.auth2 with LFK is a complex undertaking far into the future?
Can we also agree that the 30 character limitation on the username ought to be increased?
On 03/15/2012 11:48 AM, Daniel Sokolowski wrote:
> The issue here is that django auth is limited, and restrictive and needs
> hacks to make it use emails as usernames, we can agree on that yes?
Certainly.
> We
> can also agree that contrib.auth2 with LFK is a complex undertaking far
> into the future?.
It is not a simple undertaking. How far into the future it is depends
entirely on whether someone who wants to see it happen takes it upon
themselves to make it happen.
> Can we also agree that the 30 character limitation on
> the username ought to be increased?
I am not sure whether this should happen as a separate step or not. In
an ideal world, we would have a longer username field. In the real
world, we have to balance the benefit against the cost, and requiring a
schema migration from practically every Django installation on the
planet would IMO be the most significant backwards-incompatible change
Django has ever shipped, at least since Django 1.0. It is not at all
clear to me that the status quo, bad as it is, is worse than this cure.
The cost would be mitigated somewhat if we had schema migrations in
core, which would make the upgrade instructions much simpler and more
foolproof.
The cost would be reduced even more if we simply shipped this as part of
a larger customizable-auth change (which will probably require at least
a deprecation path itself).
So, in my opinion, your energies would be more productively directed
towards helping make one of those latter two things happen. But feel
free to work on a proposal to simply change the field length. If you can
provide a patch with a really compelling backwards-compatibility story,
my mind is certainly open to change.
Carl
Why would anyone waste their time working on a patch that would be
instantly rejected, as has been made patently clear throughout.
The solution to these bugs is easy, it is just being ignored because
it is 'too hard' to make these kinds of changes. Instead wishy-washy
ways of completely rewriting authentication are dreamt up, planned,
and then dropped. This is how I would fix it:
1) Fix the email length limit bug, and mark the field as a db index,
but hide this by a settings hack, called CONTRIB_AUTH_EMAIL_FIX. If
the settings hack is not set, raise a PendingDeprecationWarning
2) Add a management command 'auth_NN_inspectdb', NN being the version
number, obviously. This command introspects the auth_user table, and
determines if it needs changing, and prints out whether the table
needs updating, which could include verbatim SQL statements for their
engine. To cope with multiple databases, it takes a --database arg.
3) Add a management command 'auth_NN_updatedb'. This command
introspects the auth_user table, and if it supports the engine,
updates the DDL.To cope with mutliple databases, it takes a --database
arg.
4) Add the following release notes:
The contrib.auth.models.User model has increased the length of the
email field to 254 characters, in order to allow all legal email
addresses to be stored. In addition, the email field has been marked
as a db index, in order to more easily allow email authentication.
These changes are not made automatically by Django, sine they involve
altering the structure of your database. Instead, you must enable this
fix with by adding the settings.CONTRIB_AUTH_EMAIL_FIX. In addtion,
there are two tools included to assist you inspect your database
structure and migrate to the new structure.
<description of auth_NN_inspectdb>
<description of auth_NN_updatedb>
If you do not want to make these changes, you can instead keep using
1.4 behaviour by not adding settings.CONTRIB_AUTH_EMAIL_FIX=True. You
will receive a PendingDeprecationWarning when starting up, as this fix
will soon become default.
5) Since this scares you all so much, bump version to 2.0
6) Once released, reverse the hack in trunk so that
settings.CONTRIB_AUTH_NO_EMAIL_FIX gets you 1.4 behaviour, and warns a
DeprecationWarning.
7) Add the following relnotes to 2.1
The contrib.auth.models.User schema changes originally introduced in
2.0 are now the default. If you still do not wish to migrate your
database structure, you can keep using the 1.4 behaviour for now, by
adding settings.CONTRIB_AUTH_NO_EMAIL_FIX=True to settings.py
<info about migration commands from previous relnotes>
If you do not either set settings.CONTRIB_AUTH_NO_EMAIL_FIX or update
your database schema, then you will have problems when you encounter a
user with an email address longer than 30 characters. The exact
problem you will encounter depends upon your database:
<description of what different databases do>
I feel the amount of work involved here for your average django end
user is minimal, certainly compared to things like adding csrf tokens
throughout.
It has been made abundantly clear that this approach would not be
considered - in particular, using settings hacks to pragmatically
achieve change - so why bother pushing it any further? I love a clean
design as much as the next person, but not fixing bugs that exclude
users on grounds of 'aesthetics' is pedantic and wrong.
> How do you propose to "throw a validation error" if "the schema has not
> been updated"? How do we know whether it's been updated? Are you
> proposing that Django should introspect the users database table every
> time it starts up in order to check the length of the username field?
> Where would you put this introspection check? Have you considered the
> effects this would have on every user of contrib.auth (both those who do
> and don't run the schema migration)? And the effect on Django
> development (needing to run the tests with both an "old" and "new" table
> to ensure that the backwards-compatibility handling is tested?)
This is a bug, and fixing it will affect lots of Django users. I'm fed
up of this excuse being used to avoid fixing it.
You seem to take the view that change is too hard, and therefore we
should not do this until we have a magical solution that is all things
for all men.
Personally, I take the view that every single django site out there is
broken for 'maria.hernan...@lar.longcorpname.com', has been
for a long time, and sweet FA has been done to fix it. That view says
fix it, fix it now, because I want to be paid by the lovely Maria, not
exclude her.
I'm fed up of core devs saying that my paying users aren't important
enough to fix such a minor bug, for fear of causing issues for little
Johnny's blog.
Cheers
Tom
PS: FYI, on my django based SAML identity provider, which provides
SAML authentication for my companies network of 150+ sites has these
stats for the length of users email addresses:
mysql> select length(email) > 30 as long_email, count(*) from
auth_user group by 1;
+------------+----------+
| long_email | count(*) |
+------------+----------+
| 0 | 150493 |
| 1 | 33531 |
+------------+----------+
I'm not talking about some silly edge case that catches 0.001% of
users. 18% of my paying users have issues, if they visit a django site
made by one of my colleagues that has not been fixed to accept longer
email addresses.
I am not sure whether this should happen as a separate step or not. In
an ideal world, we would have a longer username field. In the real
world, we have to balance the benefit against the cost, and requiring a
schema migration from practically every Django installation on the
planet would IMO be the most significant backwards-incompatible change
Django has ever shipped, at least since Django 1.0. It is not at all
clear to me that the status quo, bad as it is, is worse than this cure.