A PostgreSQL extension that provides a language handler for Mustache templates using https://gitlab.com/jobol/mustach.
Variables are handled as per the mustache spec, a {{key}}
variable will be interpolated.
create or replace function win_money(you text, qt money, at timestamptz) returns text as $$
Hello {{you}}!
You just won {{qt}} at {{at}}.
$$ language plmustache;
select win_money('Sir Meowalot', '12000', now());
win_money
-----------------------------------------------------------
Hello Sir Meowalot! +
You just won $12,000.00 at 2023-12-04 07:44:26.915735-05.
(1 row)
A double mustache {{key}}
will be escaped and a triple mustache {{{key}}}
will not be escaped.
create or replace function escape_me(tag text) returns text as $$
{{tag}}
$$ language plmustache;
select escape_me('<script>evil()</script>');
escape_me
-------------------------------------
<script>evil()</script>
(1 row)
create or replace function do_not_escape_me(tag text) returns text as $$
{{{tag}}}
$$ language plmustache;
select do_not_escape_me('<script>evil()</script>');
do_not_escape_me
-------------------------
<script>evil()</script>
(1 row)
Boolean sections:
create or replace function show_cat(cat text, show bool default true) returns text as $$
{{#show}}
A cat appears, it's {{cat}}.
{{/show}}
{{^show}}
A mysterious cat is hiding.
{{/show}}
$$ language plmustache;
select show_cat('Mr. Sleepy');
show_cat
---------------------------------
A cat appears, it's Mr. Sleepy.+
(1 row)
select show_cat('Mr. Sleepy', false);
show_cat
-----------------------------
A mysterious cat is hiding.+
(1 row)
Array iterators:
create or replace function hello_cats(cats text[]) returns text as $$
Say hello to: {{#cats}}{{.}}, {{/cats}}
$$ language plmustache;
postgres=# select hello_cats('{Sir Meowalot, Mr. Sleepy, Paquito}');
hello_cats
---------------------------------------------------
Say hello to: Sir Meowalot, Mr. Sleepy, Paquito,
(1 row)
Clone the repo and submodules:
git clone --recurse-submodules https://github.com/PostgREST/plmustache
Build mustach:
cd mustach
make && sudo make install
sudo ldconfig
Build plmustache:
cd ..
make && sudo make install
Then on SQL you can do:
CREATE EXTENSION plmustache;
plmustache is tested on Postgres 12, 13, 14, 15, 16.
For testing on your local database:
make installcheck
For an isolated and reproducible enviroment you can use Nix.
$ nix-shell
$ with-pg-15 psql
$ with-pg-15 make installcheck