PostgREST Lua

A Lua library for PostgREST.

Roadmap

• authentication support
• insert support
• select support
  • basic (select wildcard)
  • vertical filtering
  • horizontal filtering
• update support
• delete support
• RPC support

Install

luarocks install postgrest

We also need to install one JSON library such as cjson or dkjson:

luarocks install dkjson

Usage

With PostgREST:

local Database = require "postgrest.database"
local cjson = require "cjson"
local api_base_url = "http://localhost:3000"
local db_instance = Database:new(api_base_url)
local todos = db_instance:from("todos"):select():execute()
-- or alternatively
local todos = db_instance("todos"):select():execute()
cjson.encode(todos)

With Supabase:

local Database = require "postgrest.database"
local cjson = require "cjson"
local project_id = os.getenv("SUPABASE_PROJECT_ID")
local public_anon_key = os.getenv("SUPABASE_PUBLIC_ANON_KEY")
local service_role_key = os.getenv("SUPABASE_SERVICE_ROLE_KEY")
local api_base_url = "https://" .. project_id .. ".supabase.co/rest/v1"
local auth_headers = {apikey = public_anon_key, authorization = "Bearer " .. service_role_key}
local supabase = Database:new(api_base_url, auth_headers)
local todos = supabase:from("todos"):select():execute()
cjson.encode(todos)

Injecting a JSON library:

local lunajson = require "lunajson"
Database:set_json_implementation(lunajson)
local todos = Database:from("todos"):select():execute()

Insert:

local values = {done = true, task = "insert support"}
db_instance:from("todos"):insert(values):execute()

Vertical filtering:

QueryBuilder:select("column1", "column2")
-- or alternatively
QueryBuilder:select{"column1", "column2"}

Horizontal filtering:

db_instance:from("todos"):select():filter{id__eq = 1}:execute()
-- or alternatively
db_instance:from("todos"):select():filter{id = 1}:execute()
-- or alternatively
db_instance:from("todos"):select():filter("id=eq.1"):execute()
-- we also support the `in` operator using tables:
db_instance:from("todos"):select():filter{id__in = {1, 2, 3}}:execute()

Same goes for other operators described in the PostgREST documentation: https://postgrest.org/en/stable/api.html#operators

Updates:

local values = {done = true, task = "learn lua"}
db_instance:from("todos"):update(values):execute()

Delete:

db_instance:from("todos"):delete():filter{id = 4}:execute()

Logger

It's possible to log the requests to the REST API by using a logger callback.

function request_logger(method, url, payload, headers)
    print("method: " .. method .. " url: " .. url)
end
Database.request_logger = request_logger

Development

Tests

Install dependencies:

make luarocks

Start the PostgreSQL database, the PostgREST service and load fixtures:

make docker/compose/recreate
make docker/compose/psql/init

Then run the tests:

make test

Teardown everything:

make docker/compose/down

Format & Lint

make format
make lint