apicall.php

<?php
// DATABASE-HOSTNAME-OR-IPADDRESS-GOES-HERE
// MYSQL-DBNAME-GOES-HERE
    class LoginHandler {
        public $dbHostname = 'DATABASE-HOSTNAME-OR-IPADDRESS-GOES-HERE';
        public $dbDatabaseName = 'MYSQL-DBNAME-GOES-HERE';
        public $user = 'DATABASE_USERNAME';
        public $password = 'DATABASE_PASSWORD';
        //public $port = 3307;
        public $message;

        public function handleRequest($arg) {
            $username = $arg['username'] ? $arg['username']: null;
            $password = $arg['password'] ? $arg['password']: null;
            if ( ! $username || ! $password ) {
                $this->fail();
                return;
            }
            try  {
                $portChunk = ( isset($this->port) ) ? ';port=' . $this->port : null;
                $dsn = "mysql:dbname={$this->dbDatabaseName};host={$this->dbHostname}{$portChunk}";
                $pdo = new PDO($dsn, $this->user, $this->password);
                $sql="SELECT * FROM `user` WHERE `username`='$username' and `password`='$password'";
                $stmt = $pdo->query($sql);
                // var_dump($stmt);
                if ( $stmt === false ) {
                    $this->message = "Query failed";
                    $this->fail();
                    return;
                }
                elseif ( $stmt->rowCount() > 0 ) {
                    $this->message = "OK";
                    $this->success();
                    return;
                }
                else {
                    $this->message = "User not found or wrong password";
                    $this->fail();
                    return;
                }
            }
            catch(PDOException $e) {
                $this->log('Connection failed: ' . $e->getMessage());
                $this->fail();
            }
        }
        function success() {
            echo json_encode(['success' => 1, 'message' => $this->message]);
        }
        function fail() {
            echo json_encode(['success' => 0, 'message' => $this->message]);
        }
        function log($msg) {
            file_put_contents("login.log", strftime('%Y-%m-%d %T ') . "$msg\n", FILE_APPEND);
        }
    }
    $handler = new LoginHandler();
    // Commend out the next line to test from the command line
    $handler->handleRequest($_POST);

    // Use this to run from the command line.
    // $ php applogin.php username aaaa password bbbb
    // $args = [$argv[1] => $argv[2], $argv[3] => $argv['4']];
    // $handler->handleRequest($args);

    // MacBook-Pro:~ me$ curl http://PUT_YOUR_HOSTNAME/apicall.php -d"username=drum&password=pass1"
    // {"success":0}
    // MacBook-Pro:~ me$ curl http://PUT_YOUR_HOSTNAME/apicall.php -d"username=drum&password=pass0"
    // {"success":1}

create_table.sql

CREATE TABLE `user` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `username` varchar(100) DEFAULT NULL,
  `password` varchar(100) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
INSERT INTO `user` (`id`, `username`, `password`)
VALUES
	(1, 'drum', 'pass');