Covid 19 Graphs Web Application

version: "3.4"
services:
  proxy:
    image: nginx:1.17.9-alpine
    deploy:
      mode: replicated
      restart_policy:
        delay: 10s
        max_attempts: 10
        window: 60s
      replicas: 4
      placement:
       # max_replicas_per_node: 1
        constraints:
          - node.labels.group==server
    ports:
      - "8080:80"
      - "9443:443"
    volumes:
      - /home/user/project_cloud/proxy.conf:/etc/nginx/conf.d/default.conf
      - /home/user/project_cloud/public.crt:/etc/nginx/public.crt
      - /home/user/project_cloud/private.key:/etc/nginx/private.key
    networks:
      - covid_19
  mysql_database:
    image: mysql:latest
    command: --default-authentication-plugin=mysql_native_password
    environment:
      MYSQL_ROOT_PASSWORD: [DATABASE ROOT PASSWORD]
    ports:
      - 3306:3306
    volumes:
      - mysql_database:/var/lib/mysql
  adminer_container:
    image: adminer:latest
    environment:
      ADMINER_DEFAULT_SERVER: mysql_db_container
    ports:
      - 6060:8080
  apache2_application:
    image: my_apache:0.1
    deploy:
      mode: replicated
      restart_policy:
        delay: 10s
        max_attempts: 10
        window: 60s
      replicas: 4
      placement:
       # max_replicas_per_node: 1
        constraints:
          - node.labels.group==server
    volumes:
      - /home/user/project_cloud/application_php/www:/var/www/html
    ports:
      - 90:80
    networks:
      - covid_19
  apache2_client:
    image: my_apache:0.1
    deploy:
      mode: replicated
      restart_policy:
        delay: 10s
        max_attempts: 10
        window: 60s
      replicas: 4
      placement:
       # max_replicas_per_node: 1
        constraints:
          - node.labels.group==server
    volumes:
      - /home/user/project_cloud/client/www:/var/www/html
    ports:
      - 91:80
    networks:
      - covid_19
volumes:
  mysql_database:
networks:
  covid_19:
    driver: overlay
secrets:
  secret_key:
    external: true
  access_key:
    external: true

proxy_cache_path /var/tmp levels=1:2 keys_zone=my_cache:10m max_size=10g inactive=60m use_temp_path=off;
server {
    listen 80;
    server_name name.example.org;
    return 301 https://83.212.77.22$request_uri;
}
server {
 listen  443 ssl;
 server_name name.example.org;
 # To allow special characters in headers
 ignore_invalid_headers off;
 # Allow any size file to be uploaded.
 # Set to a value such as 1000m; to restrict file size to a specific value
 client_max_body_size 0;
 # To disable buffering
 proxy_buffering off;
    ssl_certificate    /etc/nginx/public.crt;
    ssl_certificate_key /etc/nginx/private.key;
    ssl_protocols       TLSv1 TLSv1.1 TLSv1.2;
    ssl_ciphers         HIGH:!aNULL:!MD5;
 location /application/ {
   proxy_cache      my_cache;
   proxy_set_header X-Real-IP $remote_addr;
   proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
   proxy_set_header X-Forwarded-Proto $scheme;
   proxy_set_header Host $http_host;
   proxy_set_header X-NginX-Proxy true;
   proxy_ssl_session_reuse off;
   proxy_redirect off;
   proxy_connect_timeout 300;
   # Default is HTTP/1, keepalive is only enabled in HTTP/1.1
   proxy_http_version 1.1;
   proxy_set_header Connection "";
   chunked_transfer_encoding off;
   proxy_pass  http://apache2_client:80;
   # Health Check endpoint might go here. See https://www.nginx.com/resources/wiki/modules/healthcheck/
   # /minio/health/live;
 }
 location /services/ {
   proxy_cache      my_cache;
   proxy_set_header X-Real-IP $remote_addr;
   proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
   proxy_set_header X-Forwarded-Proto $scheme;
   proxy_set_header Host $http_host;
   proxy_set_header X-NginX-Proxy true;
   proxy_ssl_session_reuse off;
   proxy_redirect off;
   proxy_connect_timeout 300;
   # Default is HTTP/1, keepalive is only enabled in HTTP/1.1
   proxy_http_version 1.1;
   proxy_set_header Connection "";
   chunked_transfer_encoding off;
   proxy_pass  http://apache2_application:80;
 }
}

<?php
$DB_HOST = [IP];
$DB_NAME = "covid_19_db";
$DB_USER = "root";
$DB_PASSWORD = [DATABASE ROOT PASSWORD];
$CHARSET = 'utf8';
try{
    $conn = new PDO("mysql:host=$DB_HOST;port=3306;dbname=$DB_NAME;charset=$CHARSET", $DB_USER, $DB_PASSWORD);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);  // To turn on error mode for debugging errors
	$conn->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);  // To get maximum sql injection protection
   // echo "Connected successfully";
}
catch(PDOException $e){
    echo "Connection failed: " . $e->getMessage();
}
?>

var servicesURL = {
    getAllCasesGroupByContinent : 'https://83.212.77.22:9443/services/get_all_cases_group_by_continent.php',
    getContinents: 'https://83.212.77.22:9443/services/get_continents.php',
    getGroupByChooseContinent: 'https://83.212.77.22:9443/services/get_group_by_choose_continent_data.php',
    getCountries: 'https://83.212.77.22:9443/services/get_countries.php',
    getCountryDataInSpecificDates: 'https://83.212.77.22:9443/services/get_country_data_specific_dates.php',
    getLastDate: 'https://83.212.77.22:9443/services/get_last_date.php',
    getContinentsDataInSpecificDates: 'https://83.212.77.22:9443/services/get_continent_data_specific_dates.php',
    getTotalCasesAndDeaths: 'https://83.212.77.22:9443/services/get_total_cases_deaths.php'
}