Re: Libpq functions & string to obtain connection parameters

On Fri, Oct 7, 2016 at 3:15 PM Andreas Kretschmer <akretschmer(at)spamfence(dot)net>
wrote:

> arnaud gaboury <arnaud(dot)gaboury(at)gmail(dot)com> wrote:
>
> > I start an app which use a libpq function to read connection params in a
> URI.
> > Until now, the app was using a tcp connection to connect to postgresql
> with
> > this URI:
> >
> > postgres://
> mmuser:mmuser_password(at)10(dot)10(dot)10(dot)1:5432/mattermost?sslmode=disable&
> > connect_timeout=10
> >
> > I want to switch and make the app connect to the unix socket instead. I
> am
> > trying to figure out what would then be the correct URI, with no luck
> until
> > now.
>
>
> The general form for a connection URI is:
>
> postgresql://[user[:password](at)][netloc][:port][/dbname][?param1=value1&...]
>
> The URI scheme designator can be either postgresql:// or postgres://.
> Each of the URI parts is optional. The following examples illustrate
> valid URI syntax uses:
>
> postgresql:// postgresql://localhost postgresql://localhost:5433
> postgresql://localhost/mydb postgresql://user(at)localhost
> postgresql://user:secret(at)localhost
> postgresql://other(at)localhost
> /otherdb?connect_timeout=10&application_name=myapp
>
> Components of the hierarchical part of the URI can also be given as
> parameters. For example:
>
> postgresql:///mydb?host=localhost&port=5433
>
> Percent-encoding may be used to include symbols with special meaning in
> any of the URI parts.
>
> Any connection parameters not corresponding to key words listed in
> Section 31.1.2 are ignored and a warning message about them is sent to
> stderr.
>
> For improved compatibility with JDBC connection URIs, instances of
> parameter ssl=true are translated into sslmode=require.
>
> The host part may be either host name or an IP address. To specify an
> IPv6 host address, enclose it in square brackets:
>
> postgresql://[2001:db8::1234]/database
>
> The host component is interpreted as described for the parameter host.
> In particular, a Unix-domain socket connection is chosen if the host
> part is either empty or starts with a slash, otherwise a TCP/IP
> connection is initiated. Note, however, that the slash is a reserved
> character in the hierarchical part of the URI. So, to specify a
> non-standard Unix-domain socket directory, either omit the host
> specification in the URI and specify the host as a parameter, or
> percent-encode the path in the host component of the URI:
>
> postgresql:///dbname?host=/var/lib/postgresql
>
> postgresql://%2Fvar%2Flib%2Fpostgresql/dbname
>
>
>
> does that help?
>

Honestly not so much, as it is a nearly perfect Copy/past of postgresql
official doc[0].
My postgresql socket is in the usual place:
/run/postgresql/.s.PGSQL.5432=
So no need to specify it. But for the rest, I am still not sure of my URI

[0]https://www.postgresql.org/docs/9.5/static/libpq-connect.html

>
>
> (Copy&Paste from
>
> http://stackoverflow.com/questions/27037990/connecting-to-postgres-via-database-url-and-unix-socket-in-rails
> )
>
>
> Regards, Andreas Kretschmer
> --
> Andreas Kretschmer
> http://www.2ndQuadrant.com/
> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
>
>
>
>