[Dancer-users] D::P::Database: Changing Databases dynamically between routes

[Gurunandan Bhat]

Thanks David.  Responses embedded....


On Fri, Jan 27, 2012 at 5:15 PM, David Precious <davidp at preshweb.co.uk>wrote:

> On Fri, 27 Jan 2012 14:40:46 +0530
> Gurunandan Bhat <gbhat at pobox.com> wrote:
>
> > Hi,
> >
> > I am trying to use Dance::Plugin::Database with SQLite in a situation
> > where different databases must be connected to in different routes.
> > For example:
> >
> > get route_1 => sub {
> >
> >     my $dbfile_1 = "...";
> >     my $dbh = database({
> >         driver: 'SQLite',
> >         database => $dbfile_1,
> >         .... Other Options
> >     });
> >
> >     ... Work with $dbh
> >
> > }
> [...]
> > My Config file contains:
> >
> > plugins:
> >   Database:
> >     driver: 'SQLite'
> >
> > Since I dont know what the database is going to be I dont have the
> > database setting here (probably incorrect, but I dont know any better)
>
> Well, by providing a hashref of settings to the database() keyword,
> you're overriding anything in the config file anyway.
>
>
>
> > Can't connect to data source 'dbi:SQLite' because I can't work out
> > what driver to use (it doesn't seem to contain a 'dbi:driver:' prefix
> > and the DBI_DRIVER env var is not set) at
> >
> /home/nandan/perl5/perlbrew/perls/perl-5.14.2/lib/site_perl/5.14.2/Dancer/Plugin/Database.pm
> > line 163
>
> Have you accidentally called database() with no params at some point?
> That would cause that error, as it would then use the details in the
> config file, which don't contain the database name (which is of course
> required for the SQLite driver, so it knows what file to look at...)
>
>
>
I dont think so. Let me look more deeply into what exactly is happening. As
I said the first few calls (routes) succeed. It begins to fail after the
third route.



> > Could you suggest the correct way to set the database dynamically in
> > each route?
>
> You've seen Dancer::Plugin::Database's support for multiple named
> connection settings, yes/
>
>

I am aware of the named connections. Unfortunately, the functionality
required is for users to upload an SQLite file and browse the uploaded
files as well as previously uploaded files. So not only dont I know which
database the user connects to, I am also not aware of how many there are.In
this situation, I believe using name connections in this situation is not
possible?




>
> https://metacpan.org/module/Dancer::Plugin::Database#DEFINING-MULTIPLE-CONNECTIONS
>
> I would configure each database in the config file, as e.g.:
>
>     plugins:
>          Database:
>              connections:
>                  foo:
>                      driver: 'SQLite'
>                      database: 'foo.sqlite'
>                  bar:
>                      driver: 'SQLite'
>                      database: 'bar.sqlite'
>
> ... etc.
>
> Then, in your code, you can just say database('foo') to get a DB handle
> configured to talk to the 'foo' database, and database('bar') to talk
> to the 'bar' database.
>
> I think that would be far cleaner, and keeps the configuration details
> of which database to talk to out of your code, which is definitely a
> bonus - config belongs in the config file, not in the code :)
>
> Cheers
>
> Dave P
>
>
> --
> David Precious ("bigpresh") <davidp at preshweb.co.uk>
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