[Catalyst] Unable to output anything in Root.pm -> 'auto'
Craig Chant
craig at homeloanpartnership.com
Mon Oct 29 22:10:00 GMT 2012
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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