React + ES2015 + Kemal + PostgreSQL Chat Example

Chat app using React + ES2015 + Kemal + PostgreSQL

This demonstrates how easy it is to build Realtime Web applications with Kemal.

^{* This project is a fork of https://github.com/f/kemal-react-chat, but implements ES2015 and integrates with a persistent data storage with PostgreSQL*}

Requirements

• Crystal 0.18.7
• PostgreSQL (I have the v9.5.2)
• Node (I have the v5.11.1)
• NPM (I have the v3.8.6)

^{**Node and NPM are both optional if you are just going to run the app, but necessary for development since they are needed to run the gulp tasks*}

Installation

Before you can run this program you have to install the packages that it uses. You do that with $ shards install. You also need to change the path to the PostgreSQL database in src/db/init_db.cr and src/app.cr

# src/db/init_db.cr
require "pg"

# Configure these two variables
DB_NAME = "db_name"
PG_PATH = "postgres://user:password@localhost:5432"

...

# src/notes.cr
require "kemal"
require "pg"
require "./app/message"

# Configure the path of the database based on what you did in the src/db/init_db.cr file
conn = PG.connect "postgres://user:password@localhost:5432/db_name

...

Once you have installed the dependencies and configured the database path, you need to create the actual database and table for the application. You do that by running $ crystal src/db/init_db.cr.

Run Project

You can run this program in two ways:

1. Compile/build the project using the command line with $ crystal build src/app.cr --release and run the executable $ ./app
2. Run the program with $ crystal src/app.cr (no compilation required)

Once you have run the program, you can open a browser window at localthost:3000 and see the actual app.

Live Demo

You can see and use a live demo of the app here: kemal-react-pg-chat.herokuapp.com.