PostGraphile simple example

This is a simple demo project that I (@benjie) use during some presentations. It is not intended to be a full example of how to use PostGraphile; better places to look are the docs, or the bootstrap-react-apollo repo.

Setup:

First we need to install all the dependencies with yarn. (If you don't have yarn installed, you can install it with npm install -g yarn.)

Then we need to create a graphile_example repo, an unprivileged graphql database role, and load schema.sql into this graphile_example repo. All of this is handled for us by the yarn setup command.

Finally we run postgraphile in watch mode.

yarn
yarn setup
./node_modules/.bin/postgraphile --watch

The demo

Copy and paste chunks from demo.sql into the database as you go. To open a connection to the database, run:

psql graphile_example

Jump to the end

If you prefer to load everything up front rather than step-by-step, you can install everything in the demo with this one command:

psql -Xv ON_ERROR_STOP=1 -f demo.sql graphile_example

Smoke and mirrors

Settings are loaded from .postgraphilerc.js to avoid having to write too many CLI flags. The various options that we used are documented in that file.

The current_user_id() function just returns the static number 1. In a real app you'd replace this with something like:

create or replace function current_user_id() returns int as $$
  select nullif(current_setting('jwt.claims.user_id', true), '')::int;
$$ language sql stable;

(Note that jwt.claims.user_id is only an example, you can substitute authentication with whatever you like.)

If you're concerned your database connection string could ever be leaked, you might go with something a bit more paranoid, such as:

create or replace function current_user_id() returns int as $$
  select user_id
  from app_private.sessions
  where secret = nullif(current_setting('jwt.claims.session_secret', true), '')::uuid;
$$ language sql stable;

To read more, see our Row Level Security infosheet, our JWT security guide, or the passport.js implementation in the bootstrap repo.

Cleanup:

To delete the database and the user, run:

yarn cleanup