How to get text for a plpgsql variable from a file.

Hello,

I need a long text form from a file in my plpgsql variable.
Can anyone think of a more straightforward way to read the file than
the following:

CREATE FUNCTION test() RETURNS void AS
$BODY$
DECLARE
mytxt text;
BEGIN

CREATE TEMP TABLE x (x text);
COPY x from '/path/to/myfile.txt';
mytxt := (SELECT x from x);

...

END;
$BODY$
LANGUAGE 'plpgsql' VOLATILE;

Regards
Erwin