Server.ktor-chat

Server for the Ktor-chat app

Backend for KtorAndroidChat app: https://github.com/realityexpander/KtorAndroidChat

Test locally without android app

Use this WebSocket testing site for local testing. (Does not work with the deployed server)

https://www.piesocket.com/websocket-tester

Websocket local url: ws://localhost:8082/chat-socket?username=Jimbo

Deployment Steps

1. Download Git Bash (only if on Windows)

2. Go to your users folder and open the ~/.ssh folder. Then open Git Bash / Terminal there and generate a key pair:

ssh-keygen -m PEM -t rsa -b 2048

Give it the (I suggest hostinger_rsa)

3. Copy the key to your server:

ssh-copy-id -i <keyname> <user>@<host>

4. Make a local /key folder and copy the file to your local app dev /key folder.

The file should look like this inside:

-----BEGIN RSA PRIVATE KEY-----
MIIG4wIBAAKCAYEAxSXsSpaIlJRKF11qpQEaBwnrn5Xv4EelL/Iqpn7VBRnLdefz
QE9lHmF5oVB6Em1MEXJVzs+X6CZRSVTYGezWjmy/v/07aaiGZX1MgXjS0Q6DzKPC
...
-----END RSA PRIVATE KEY-----

5. Login to your Ubuntu server via SSH:

ssh -i <keyname> <user>@<host>

6. Update dependencies:

sudo apt update

7. Install Java:

sudo apt-get install default-jdk

8. Open /etc/ssh/sshd_config:

sudo nano /etc/ssh/sshd_config

9. Put this string in there, save with Ctrl+S and exit with Ctrl+X:

KexAlgorithms [email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1

10. Restart the sshd service:

sudo systemctl restart sshd

11. Create a systemd service for your Ktor server:

sudo nano /etc/systemd/system/chat.service

12. Paste this configuration in this service, then save with Ctrl+S and exit with Ctrl+X:

[Unit]
Description=Chat Service
After=network.target
StartLimitIntervalSec=10
StartLimitBurst=5

[Service]
Type=simple
Restart=always
RestartSec=1
User=root
ExecStart=sudo java -jar /root/chat/chat-server.jar

[Install]
WantedBy=multi-user.target

13. Launch the service:

sudo systemctl start chat

14. Create a symlink to automatically launch the service on boot up:

sudo systemctl enable chat

15. Make sure, your ports are open and you forward the traffic from the standard HTTP port to 8082:

iptables -t nat -I PREROUTING -p tcp --dport 80 -j REDIRECT --to-ports 8082
sudo iptables -A INPUT -p tcp --dport 80 -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 8082 -j ACCEPT

16. Then, save your iptables rules:

sudo apt-get install iptables-persistent

17. Install MongoDB

apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 9DA31620334BD75D9DCB49F368818C72E52529D4
echo "deb [ arch=amd64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/4.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb.list
apt-get update
apt-get install mongodb-org
systemctl unmask mongod
systemctl enable mongod
systemctl restart mongod

18. Make sure the folder /root/chat/ exists

cd /root
mkdir chat

19. Add environement file in /root/chat/

nano environment

MONGO_USERNAME="ADMIN_USERNAME_IN_QUOTES"
MONGO_PASSWORD="PASSWORD_IN_QUOTES"
MONGO_HOST=localhost
MONGO_PORT=27017
MONGO_AUTH_SOURCE=admin

ctrl-s, ctrl-x

20. Deploy automatically with gradle

On local dev machine terminal: ./gradlew deploy

Be sure to add the user and password to the Mongo Admin database! OR IT WILL DEFINITELY BE HACKED!!!

Create an admin user from MongoSh (mongo shell) or Mongo Compass

 use admin
 
 db.createUser({user: "ADMIN_USERNAME", pwd: "PASSWORD_RAW_NO_EXTRA_QUOTES", roles: [{role: "readWrite", db: "admin"}]})

or this option (which you will be prompted for the password, so it wont be visible like the above step):

 db.createUser({user: "ADMIN_USERNAME", pwd: passwordPrompt(),
   roles: [
     { role: "userAdminAnyDatabase", db: "admin" },
     { role: "readWriteAnyDatabase", db: "admin" }
 ]})

Auth the user:

 use admin
 db.auth("ADMIN_USERNAME", passwordPrompt()) // or cleartext password

Show users:

 use admin
 db.system.users.find()

Remove user:

 use admin
 db.system.users.deleteOne({user: "user"})

Trouble shooting

May need to run to reset chat.service (on remote ubuntu server):

systemctl daemon-reload