[dancer-users] how to make sure one db connection per user

Dancer New dancerfan2015 at gmail.com
Mon Sep 21 10:51:58 BST 2015

On Fri, Sep 18, 2015 at 5:39 PM, Maxwell Carey <mcarey at ucar.edu> wrote:

> On Fri, Sep 18, 2015 at 10:32 AM, WK <wanradt at gmail.com> wrote:
>> Hi!
>> 2015-09-18 19:09 GMT+03:00 Dancer New <dancerfan2015 at gmail.com>:
>> > I use Dancer::Plugin::Database in my application. Each time when
>> > $dbh = DBI->connect( $c->{ dsn }, $c->{ username }, $c->{ password},
>> $c->{
>> > dbi_params })
>> > is called. does it return a new connection?
>> Yes, it does. But then is no point to use Dancer::Plugin::Database at all.
> To expand on this a little, with Dancer::Plugin::Database, you should be
> using the 'database' function instead of calling DBI->connect. See the
> documentation here
> https://metacpan.org/pod/Dancer::Plugin::Database#GETTING-A-DATABASE-HANDLE
> "Calling database will return a connected database handle; the first time
> it is called, the plugin will establish a connection to the database, and
> return a reference to the DBI object. On subsequent calls, the same DBI
> connection object will be returned, unless it has been found to be no
> longer usable (the connection has gone away), in which case a fresh
> connection will be obtained."

Thanks for the explanation.

>> > I would like one db connection for each user, where can I save the
>> database
>> > handler?
>> Could you elaborate, why every user must have their own connection? It
>> does not seem reasonable. Using just one connection over the
>> application is much cheaper way. When using Dancer::Plugin::Database
>> you must set up connection data in config file.
> You can define multiple connections so that database('foo') will connect
> with one set of connection parameters and database('bar') will use another.
> See
> https://metacpan.org/pod/Dancer::Plugin::Database#DEFINING-MULTIPLE-CONNECTIONS
> But I agree, this seems like a bad idea. What exactly are you trying to do?
I want to make sure each user only see their own data.
So in the database, I have a procedure to set the context. By calling this
procedure, it records that this database session is for the particular
user, any subsequent queries is for the particular user.

If I use the same database connection for all of the queries, when a user
comes in and the database set context for the user, but at the same time
another user comes in,  then will the database think it is the previous
user, and return the data of the previous user to the new user?

If I don't use one database connection for each user, how can I make sure
the database handler know which user it is dealing with?

Many thanks,

> dancer-users mailing list
> dancer-users at dancer.pm
> http://lists.preshweb.co.uk/mailman/listinfo/dancer-users
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