Richard Huxton wrote:
D. Dante Lorenso wrote:
I want to use the ENCRYPT and DECRYPT functions from contrib, but they
require inputs of BYTEA.
My data is in VARCHAR and TEXT fields and when I try to use the
contrib functions, they complain about wrong datatypes. Is there a
string function or something that will take a VARCHAR or TEXT input
and output a BYTEA so that I can use that as input for the
ENCRYPT/DECRYPT functions?
I know about creating a CAST from VARCHAR to BYTEA, but the problem
with a CAST is that it doesn't port to other database servers when I
do a dump and restore.
Doesn't it?
Hmm... seems to dump for me in 8.2
My CAST was defined as follows:
CREATE CAST (VARCHAR AS BYTEA) WITHOUT FUNCTION;
Tom explains why that does NOT dump and restore with my database here:
http://archives.postgresql.org/pgsql-general/2007-11/msg00922.php
http://archives.postgresql.org/pgsql-general/2007-11/msg00931.php
Likely my problem is that I don't use a function to do the cast.
> That forces me to manually have to recreate the cast
each time a new database is set up and usually that's the step that
gets forgotten.
Surely you have a script that creates your databases for you?
Is this enough script?:
DUMP:
/usr/bin/pg_dump -U [user] -Ft [dbname] > [tar_file]
RESTORE:
/usr/bin/pg_restore -c -Ft [tar_file] | /usr/bin/psql -U [user] [dbname]
Is there a function that will do what I want to convert the datatype
without having to create a CAST that PostgreSQL doesn't have natively?
How else are you supposed to use the ENCRYPT and DECRYPT functions?
With actual bytea types?
Sure, bytea works, but I want this to work:
SELECT DECRYPT(ENCRYPT('cheese', 'secret', 'bf'), 'secret', 'bf');
I don't see any BYTEA in there ...
Anyway this will convert for you - PG can get from an unknown quoted
literal to bytea just fine.
CREATE FUNCTION text2bytea(text) RETURNS bytea AS $_$
DECLARE
b bytea;
BEGIN
EXECUTE 'SELECT ' || quote_literal($1) || '::bytea' INTO b;
RETURN b;
END
$_$
LANGUAGE plpgsql;
Awesome! That's just what I was looking for!
And here's the cast definition that goes with it
CREATE CAST (text AS bytea) WITH FUNCTION public.text2bytea(text);
Perfect. And now that this CAST depends on a function which is in my
database, it should dump and restore without a problem.
Let me go test all this ... YEP THAT WORKS!
Thanks again!
-- Dante
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