Re: Inserting .png file into bytea column

On Thu, Nov 19, 2015 at 6:19 AM, Achilleas Mantzios <
achill(at)matrix(dot)gatewaynet(dot)com> wrote:

> On 19/11/2015 16:07, Ferrell, Denise D CTR NSWCDD, H11 wrote:
>
> Good Morning All,
>
> I am using PostgreSQL 9.3 on Linux Rehat...
>
> I'm trying to insert an image (.png format) into a table of flags. I've tried the following but keep getting errors.
>
> CREATE TABLE FLAGS (country_code text, flag bytea);
>
> INSERT INTO flags VALUES ('AD', pg_read_file('/home/flags')::bytea);
>
> Get the following error:
> ERROR: absolute path not allowed
> *********ERROR*************
> ERROR: absolute path not allowed
> SQL State: 42501
>
> Any assistance would be greatly appreciated.
>
>
>
> http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADMIN-GENFILE
>
> use pg_read_binary_file(filename text [, offset bigint, length bigint])
> as documented
>

The documentation you linked to explains the problem:

The functions shown in Table 9-66 provide native access to files *on the
machine hosting the server*. Only files *within the database cluster
directory* and the log_directory can be accessed. *Use a relative path* for
files in the cluster directory, and a path matching the
log_directoryconfiguration setting for log files. Use of these functions is
restricted to superusers.

You can't access files on the client side, and on the server side you can
only access files that are internal to Postgres (e.g. inside
/data/postgres, or whatever path your Postgres uses for the database). And
only super-users can use this function at all because it allows access to
sensitive server files.

The easiest way to do this on the client side is to read the file into a
client-side variable and then use a prepared statement. In Perl, something
like this:

use DBI;
my $dbh = $dbi->connect(...);

my $photo;
open(PHOTO, "/home/flags");
binmode PHOTO;
while (<PHOTO>) {
$photo .= $_;
}
my $sth = $dbh->prepare("insert into flags(country_code, flag) values(?,
?)");
$sth->execute('AD', $photo);

Craig

> Denise Ferrell
>
>
>
> --
> Achilleas Mantzios
> IT DEV Lead
> IT DEPT
> Dynacom Tankers Mgmt
>
>

--
---------------------------------
Craig A. James
Chief Technology Officer
eMolecules, Inc.
---------------------------------