Running system command with argument in a PostgreSQL function - linux

Question

I'm not sure if I was specific in the question, but I'm having trouble creating a Postgres function that runs a Linux shell command, with one detail: it's a function in a Trigger after insert and I need to use some NEW columns.
While in MySQL, using the plugin "MySQL UDF" it was pretty simple, trigger worked like this:
BEGIN
DECLARE result int(10);
SET result = sys_exec('/usr/bin/php /var/www/html/.../regras.php NEW.uniqueid NEW.linkedid NEW.eventtype');
END
But on PostgreSQL I tried the language PL/sh, wich enables running any shell script, so I wrote the following function:
CREATE FUNCTION tarifador_func2() RETURNS TRIGGER
LANGUAGE plsh
AS $$
#!/bin/sh
/usr/bin/php /var/www/html/...regras.php NEW.uniqueid NEW.linkedid NEW.eventtype
$$;
It does execute the .php file in proper way, the problem is the language does not recognize the NEW variables I'm giving as arguments to the PHP, so in the args[] what I got is "NEW.uniqueid", "NEW.linkedid" and "NEW.eventtype".
So, anyone knows how can I properly use the NEW argument in PL/sh?
Another possible solution might be to manually set the three values I need via the arguments on crating the trigger, but it's not allowed to use NEW in the arguments.

Answer 1

You can access some values in plsh triggers.
UPDATE offers only OLD
INSERT offers only NEW (duh)
DELETE I didn't test
So you get those values using arguments, like $1, $2
You function would look kinda like this:
CREATE FUNCTION tarifador_func2() RETURNS TRIGGER
LANGUAGE plsh
AS $$
#!/bin/sh
/usr/bin/php /var/www/html/...regras.php $3 $6 $1
$$;
Notice that I didn't use $1 $2 $3, that is because plsh extension dumps ALL columns into arguments in order they are declared in your table. So you might do something like INSERT INTO table1 (column3) VALUES (6); and it will be under $3 in plsh, assuming this is third column in table.
As a side note, metadata of trigger is available thru env vars.

Answer 2

As far as I know, you cannot access the NEWand OLD tuple in PL/sh.
I would use PL/Perl or PL/Python for this purpose.
Here is an example in PL/Python:
CREATE OR REPLACE FUNCTION pytrig() RETURNS trigger
LANGUAGE plpythonu AS
$$import os
os.system("/usr/bin/php /home/laurenz/hello.php '" + TD["new"]["val"] + "'")$$;
CREATE TABLE test (id integer PRIMARY KEY, val text);
CREATE TRIGGER pytrig AFTER INSERT ON test FOR EACH ROW
EXECUTE PROCEDURE pytrig();