[Catalyst] Unable to output anything in Root.pm -> 'auto'

[Lukas Thiemeier]

On 10/29/2012 11:30 PM, Rob Brown wrote:
> basically...
>
> $sth->finish if you've finished with the results of that statement, ie,
> you've looped through the rows and are now done.
>
> $dbh->disconnect if you've finished with the database connection, tho
> now you start to think about working in a persistent environment, where
> you may never disconnect from the database, and/or have some connection
> caching setup.
>
> This is where DBIx::Class just takes of all this for you - it does sound
> like you're re-inventing a lot here.
>
> What was the reason for not using DBIC again?
>

Right.

If you need more help about DBI, dbi-users at perl.org is a better place to 
ask.

Not that we catalyst users are not willing to help you, but most people 
here know much about Catalyst, and not-as-much about DBI.

Feel free to ask your DBI questions here, but if it comes to DBI 
details, the people reading dbi-users at perl.org are, well, more 
qualified. The chance to get helpful answers (or any answers at all, for 
more special/difficult questions) is much higher if you post to the 
right list...

Lukas

>
>
>
> On 10/29/2012 10:10 PM, Craig Chant wrote:
>> I finally got to grips with extending my own class with the inbuilt
>> $c->dbh.
>>
>> But am unsure whether I am mean to issue either...
>>
>> $sth->finish();
>>
>> or
>>
>> $dbh->disconnect();
>>
>> Once I have prepared / executed the SQL and fetched the records I want.
>>
>> so a little further guidance is appreciated.
>>
>> Craig
>>
>> ________________________________________
>> From: Lukas Thiemeier [spamcatcher at thiemeier.net]
>> Sent: 29 October 2012 20:16
>> To: catalyst at lists.scsys.co.uk
>> Subject: Re: [Catalyst] Unable to output anything in Root.pm -> 'auto'
>>
>> Hi Craig,
>>
>> Using C::M::DBI is straight forward. Install it from cpan, and run
>>
>> script/yourapp.pl create model DBI DBI dsn user password
>>
>> where "dsn" is sth like "dbi:mysql:dbname", depending on your backend.
>>
>> If it doesn't work you most likely have some typo in your dsn, username
>> or password.
>>
>> When this doesn't work, what error is printed?
>> What was your input (except passwd, of course)?
>>
>> Something like $c->dbh doesn't exist. The database handler belongs to
>> the model, and you can create Cat applications with several models, or
>> without any model at all. (Or with a model which is not a
>> database-model, or, or ...)
>>
>> $c->model('DBI')->dbh does the trick.
>>
>> The name "DBI" is required by C::A::Store::DBI, but besides this, any
>> model name is fine.
>>
>> Alternatively, add a shortcut to your main App.pm:
>>
>> sub dbh{ shift->model("DBI")->dbh }
>>
>> Now, $c->dbh is available.
>>
>> Session timeouts et cetera are configurable in the session plugin.
>> The session keeps track of when it was created, and when it was updated.
>>
>> Setting extra fields (in the session or in the database), which are not
>> automatically set by the authentication plugin, can easily be done by
>> you, even if you use a authentication plugin. You can do this in the
>> "auto" action, for example.
>>
>> I can only suggest you to search for existing modules, and use them
>> whenever possible. Thanks to Moose, extending a catalyst module is easy
>> in most cases. And it is much less work than writing everything from
>> scratch.
>>
>> In my opinion, the biggest benefit of catalyst is (besides its great
>> backwards compatibility), that it is very modular, dozens of modules
>> exist, and most modules are extendable and reusable.
>>
>> If you try to write all your code by yourself, you will not get happy.
>>
>> Another suggestion: Maybe you should first forget about your real
>> applicationfor now, and just work through the catalyst tutorial. You can
>> finish it in some hours (depending on your perl- and web knowledge).
>> It will give you a great overview about how Catalyst works, what is
>> possible (almost everything) and what isn't possible (almost nothing) :)
>>
>> Or maybe you don't need a monster like catalyst? "Dancer" might be an
>> option.
>>
>> Dancer is a perl MVC Framework, too. It is much smaller and simpler than
>> Catalyst, has less dependencies and less modules and (at least I was
>> told so) is easier to learn. It does not do as much for you as catalyst
>> does (in most cases, you have to write more code). But if you have to
>> reinvent the wheel again and again anyway, it might be a better choice.
>>
>> Don't get me wrong. I don't suggest you to let catalyst go. Catalyst
>> rocks! But if most of the benefits are really not an option for you, you
>> should think about alternatives.
>>
>>
>> And finally: Don't make unpaid overtime: Go and get a beer! NOW!
>> Catalyst will be more fun tomorrow!
>>
>>
>> Ooops, I am writing this while making unpaid overtime. I will go and get
>> a beer :)
>>
>> bye, Lukas
>>
>>
>>
>>
>> On 10/29/2012 08:25 PM, Craig Chant wrote:
>>> Hi Lukas,
>>>
>>> I tried to use C::Model::DBI , but I cannot get it to work?
>>>
>>> I've ended up refactoring my own SQL module from the exisitng app as
>>> OOP and then as an extension of Catayst::Model
>>>
>>> I then create my own Model which extends my SQL module and I've got
>>> it working.
>>>
>>> No matter what I tried , I couldn't find $c->dbh , I really seem to
>>> be struggling at the moment getting my head round Catalyst, but I am
>>> persevering!
>>>
>>> I was hoping to use the built in DBI functionality, as it is meant to
>>> keep database handles / connections open etc..but $c->dbh didn't
>>> exits in my Model when I created it via myapp_create.pl MODEL DBI
>>>
>>> I also appreciate there is a lot of stuff already written such as the
>>> authentication mechanism, but will that update my backend DB with the
>>> current location of the user?
>>>
>>> Does it have a mechanism to enable 'heartbeat' to keep idle sessions
>>> open?
>>>
>>> Will it keep up-to-date the date / time field so we can see at a
>>> glance the length of time a user has been logged on via our admin
>>> system?
>>>
>>> Or does it simply keep a state of whether the user is loged in or not?
>>>
>>> I also know that I should look at ORM and DBIC, but one thing at a
>>> time, Rome wasn't built in a day, and playing with Catalyst is simply
>>> something I want to do, not a requirement of my Job.
>>>
>>> I start a 10 month SQL course in January, where I'm sure I will learn
>>> about DB's in far more detail and can then consider ORM / DBIC.
>>>
>>> There is only so many hours in the day, then there are only so many I
>>> am paid to work and then there is only so much information I can
>>> absorb in one go!
>>>
>>> I'm already sitting here doing unpaid overtime, but I'm commited to
>>> getting Catalyst working, so don't mind putting in the extra hours,
>>> sounds sad I know, but I am enjoying it, even if I seem frustrated at
>>> times.
>>>
>>> Thank for all the input.
>>>
>>> Craig.
>>>
>>> ________________________________________
>>> From: Lukas Thiemeier [spamcatcher at thiemeier.net]
>>> Sent: 29 October 2012 19:03
>>> To: catalyst at lists.scsys.co.uk
>>> Subject: Re: [Catalyst] Unable to output anything in Root.pm -> 'auto'
>>>
>>> Hi Craig,
>>>
>>> You are NOT wrong. Catalyst allows you to do so. I think it is the right
>>> choice.
>>>
>>> For C::A::Store::DBI - What you need is to provide the user_table,
>>> user_key and user_name, and the password_field and password_type for the
>>> credential part. I guess you have this, haven't you?
>>>
>>> All the "role" stuff is optional and only required if you want to use
>>> Catalyst::Plugin::Authorization::Roles (which you don't want if I got
>>> you right).
>>>
>>> I would suggest you to use as much existing code as possible, and only
>>> rewrite what you really need.
>>>
>>> In your case:
>>> Use C::A::Store::DBI for authentication and C::Model::DBI to access your
>>> database.
>>> If you do so, you only have to write your own authorization code (roles
>>> etc) and your CRUD stuff. You can access your db using DBI, without ORM
>>> or any assumptions to the db layout.
>>>
>>> If you can not use C::A::Store::DBI for any reasons, I would still
>>> recommend you to either write your own Catalyst::Authentication::Store
>>> and/or Catalyst::Authentication::Credential modules (I guess a
>>> Store-module will do the trick). You will not have to deal with
>>> user-sessions and related stuff. Just tell Catalyst how to authenticate
>>> the user, and let catalyst itself deal with the session.
>>>
>>> Catalyst::Plugin::Authentication::Internals tells you how to write your
>>> own store and credential modules. You will have to read the docs first,
>>> but I am sure that this is less work than writing ALL your
>>> authentication, session handling and authorization code by yourself.
>>>
>>> When it comes to reusability, Catalyst is unbeatable :)
>>>
>>> If you want or need to write your own authentication code in your
>>> controller classes, you should still use $c->session directly. Don't
>>> fiddle with the session id. Doing so is error-prone, and not required.
>>> You can do it like this:
>>>
>>> unless(defined $c->session->{user}){;
>>> my $user = your_auth_code(\%data);
>>> $c->session(user => $user);
>>> }
>>>
>>> You can later access it in any controller by saying:
>>>
>>> my $user = $c->session->{user}
>>>
>>> You can even make a shortcut in your App.pm:
>>>
>>> sub is_authenticated{ defined( shift->session->{user}) }
>>>
>>> And later check if the user is authenticated like this:
>>>
>>> if($c->is_authenticated){
>>> do_some_privileged_stuff();
>>> }
>>>
>>>
>>> You should consider using DBIx::Class anyway. It doesn't require
>>> normalized databases. Automated model generation might not work
>>> correctly, but in general you can use it on any database. DBIx::Class is
>>> well documented, easy to learn, and it makes database access simple and
>>> safe. Without ORM, you will most likely have to write 10 times more
>>> database-code, and you will have to double check it to ensure that you
>>> are not vulnerable to sql injections.
>>>
>>> You are not forced to use DBIC relationships et cetera. You can just use
>>> it to update your tables, and only use the rels where you have them in
>>> your db layout.
>>>
>>> In my opinion, the reasons not to use DBIC are:
>>>
>>> 1: it takes some time to install, but you only have to do it once.
>>>
>>> 2: it slows down the startup time for your application, but unless you
>>> are using plain CGI, this doesn't really matter. (If you use
>>> plain-old-CGI, STOP doing so. Use FastCGI instead.)
>>>
>>> 3: It sometimes generates more SQL statements than it is required to
>>> fulfill a certain task, but this is only relevant if you are running a
>>> high performance, high traffic site. And IF this is the case, you can
>>> still optimize it.
>>>
>>> If you compare it to the benefits I described above, the benefits are
>>> dominant in most cases.
>>>
>>> I know that this is not the universal truth (which doesn't exist
>>> anyway). It is my personal opinion. Just think about it.
>>>
>>> Additionally: DBIC makes moving from one database system to another very
>>> very easy. You have a SQLite DB, and want to move to Portgresql?
>>> no problem. With DBIC, you are already done :)
>>>
>>> Ok. I hope I could help.
>>>
>>> Sorry for the DBIC-praising at the end. It is just that I first didn't
>>> want to use DBIC, too. And now I see how much easier my life is with
>>> DBIC, and I think I should have moved to DBIC earlier.
>>>
>>> Lukas
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On 10/29/2012 06:00 PM, Craig Chant wrote:
>>>> Hi Luka,
>>>>
>>>> Perhaps I miss-read the info on
>>>> http://search.cpan.org/~janus/Catalyst-Authentication-Store-DBI-0.01/lib/Catalyst/Authentication/Store/DBI.pm
>>>>
>>>>
>>>> But from what I can see it expects you to map specific fields in a
>>>> table as well as have a user role table with specific data mapping?
>>>>
>>>> [quote] __PACKAGE__->config->{'authentication'} = {
>>>> 'default_realm' => 'default',
>>>> 'realms' => {
>>>> 'default' => {
>>>> 'credential' => {
>>>> 'class' => 'Password',
>>>> 'password_field' => 'password',
>>>> 'password_type' => 'hashed',
>>>> 'password_hash_type' => 'SHA-1',
>>>> },
>>>> 'store' => {
>>>> 'class' => 'DBI',
>>>> 'user_table' => 'login',
>>>> 'user_key' => 'id',
>>>> 'user_name' => 'name',
>>>> 'role_table' => 'authority',
>>>> 'role_key' => 'id',
>>>> 'role_name' => 'name',
>>>> 'user_role_table' => 'competence',
>>>> 'user_role_user_key' => 'login',
>>>> 'user_role_role_key' => 'authority',
>>>> },
>>>> },
>>>> },
>>>> };[/quote]
>>>>
>>>> Have I read the above incorrectly?
>>>>
>>>> I have a non-normalised DB , with an application that functions in a
>>>> particular way, I deal with user roles and other such stuff in my
>>>> own way and I cannot refactor to use catalyst without ensuring all
>>>> sections of the system function the same along with the back end
>>>> admin system, I can't rewrite both parts at the same time, this is a
>>>> live app in production that works currently, I'm simply trying to
>>>> learn Catalyst& MVC cuteness, not start from scratch.
>>>>
>>>> > From what I can see using any of those authentication modules
>>>> expects certain data I don't have or use nor want.
>>>>
>>>> Please correct me if I'm reading the CPAN documentation incorrectly.
>>>>
>>>> I want to refactor my app to be MVC using Catalyst without being
>>>> forced to do any other than MVC cuteness and work the way I want to
>>>> with the a database that already exists, I got the feeling Catalyst
>>>> allows this unlike ROR or other MVC frameworks.
>>>>
>>>> Again, have I got this wrong?
>>>>
>>>> If to use Catalyst I have to have a normalised DB, use specific
>>>> modules with data in a particular format, then I will just refactor
>>>> our systems myself using my own modules and such, best to find this
>>>> out now before I spend any more time on something that isn't suitable.
>>>>
>>>> Thanks,
>>>>
>>>> Craig.
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Lukas Thiemeier [mailto:spamcatcher at thiemeier.net]
>>>> Sent: 29 October 2012 16:42
>>>> To: catalyst at lists.scsys.co.uk
>>>> Subject: Re: [Catalyst] Unable to output anything in Root.pm -> 'auto'
>>>>
>>>>
>>>> Hey Craig,
>>>>
>>>> I got it. You want to store your credentials in a database, but you
>>>> don't want to use DBIx::Class?
>>>>
>>>> What about Catalyst::Authentication::Storage::DBI?
>>>>
>>>> If this doesn't help, you might me right. Maybe you have to write
>>>> your own authentication module. In that case, consider making it a
>>>> Catalyst::Authentication::Store module, and publish it on cpan. It
>>>> might be useful for others, too...
>>>>
>>>> By the way: Catalyst::Model::DBI is a ORM-less, raw DBI model for
>>>> catalyst. So "... whenever I look at how it implements anything to
>>>> do with DB access, it forces ORM upon you ..." is not correct. There
>>>> are very few things which are really forced by catalyst. Using
>>>> DBIx::Class is just considered "good practice". A lot of people use
>>>> it, thats why it is used in most tutorials and examples.
>>>>
>>>> Lukas
>>>>
>>>>
>>>>
>>>> On 10/29/2012 05:09 PM, Craig Chant wrote:
>>>>> Yes, but I need to keep a backed DB up-to-date with current logins,
>>>>> where in the system they are etc...
>>>>>
>>>>> So local server disk won't help in this situation.
>>>>>
>>>>> -----Original Message-----
>>>>> From: Denny [mailto:2012 at denny.me]
>>>>> Sent: 29 October 2012 15:50
>>>>> To: The elegant MVC web framework
>>>>> Subject: RE: [Catalyst] Unable to output anything in Root.pm -> 'auto'
>>>>>
>>>>> On Mon, 2012-10-29 at 15:43 +0000, Craig Chant wrote:
>>>>>> "By the way, what do you need the session-id for? Catalyst handles
>>>>>> sessions in a transparent way"
>>>>>>
>>>>>> To authenticate users, I don't want to store authentication in the
>>>>>> hash and it seems the only other way to do this is via ORM, which
>>>>>> I don't want to use either.
>>>>>>
>>>>>> I find catalyst whenever I look at how it implements anything to
>>>>>> do with DB access, it forces ORM upon you, so I need to write my
>>>>>> own authentication code don't I ?
>>>>>
>>>>> I'm pretty sure the default storage for session stuff is disk-based.
>>>>>
>>>>>
>>>>>
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