controllers.php

<?php

// koneksi ke database
$conn = mysqli_connect("localhost", "root", "", "students");

function query($query)
{
	global $conn;
	$result = mysqli_query($conn, $query);
	$rows = [];
	while ($row = mysqli_fetch_assoc($result)) {
		$rows[] = $row;
	}
	return $rows;
}

function store($data)
{
	global $conn;

	$absen = htmlspecialchars($data["absen"]);
	$nama = htmlspecialchars($data["nama"]);
	$jurusan = htmlspecialchars($data["jurusan"]);

	// upload gambar
	$gambar = upload();
	if (!$gambar) {
		return false;
	}

	$query = "INSERT INTO siswa (absen, nama, jurusan, gambar) VALUES
	('$absen', '$nama', '$jurusan', '$gambar')";
	mysqli_query($conn, $query);

	return mysqli_affected_rows($conn);
}

function upload()
{
	$namaFile = $_FILES['gambar']['name'];
	$ukuranFile = $_FILES['gambar']['size'];
	$error = $_FILES['gambar']['error'];
	$tmpName = $_FILES['gambar']['tmp_name'];

	// cek apakah tidak ada gambar yang diupload
	if ($error === 4) {
		echo "<script>
				alert('pilih gambar terlebih dahulu!');
			</script>";
		return false;
	}

	// cek apakah yang diupload adalah gambar
	$ekstensiGambarValid = ['jpg', 'jpeg', 'png'];
	$ekstensiGambar = explode('.', $namaFile);
	$ekstensiGambar = strtolower(end($ekstensiGambar));
	if (!in_array($ekstensiGambar, $ekstensiGambarValid)) {
		echo "<script>
				alert('yang anda upload bukan gambar!');
			</script>";
		return false;
	}

	// cek jika ukurannya terlalu besar
	if ($ukuranFile > 1000000) {
		echo "<script>
				alert('ukuran gambar terlalu besar!');
			</script>";
		return false;
	}

	// lolos pengecekan, gambar siap diupload
	// generate nama gambar baru
	$namaFileBaru = uniqid();
	$namaFileBaru .= '.';
	$namaFileBaru .= $ekstensiGambar;

	$oke = move_uploaded_file($tmpName, 'img/' . $namaFileBaru);
	return $namaFileBaru;
}

function destroy($id)
{
	global $conn;
	mysqli_query($conn, "DELETE FROM siswa WHERE id = $id");
	return mysqli_affected_rows($conn);
}

function update($data)
{
	global $conn;

	$id = $data["id"];
	$absen = htmlspecialchars($data["absen"]);
	$nama = htmlspecialchars($data["nama"]);
	$jurusan = htmlspecialchars($data["jurusan"]);
	$gambarLama = htmlspecialchars($data["gambarLama"]);

	// cek apakah user pilih gambar baru atau tidak
	if ($_FILES['gambar']['error'] === 4) {
		$gambar = $gambarLama;
	} else {
		$gambar = upload();
	}


	$query = "UPDATE siswa SET
				absen = '$absen',
				nama = '$nama',
				jurusan = '$jurusan',
				gambar = '$gambar'
			WHERE id = $id
			";

	mysqli_query($conn, $query);

	return mysqli_affected_rows($conn);
}

function search($keyword)
{
	$query = "SELECT * FROM siswa
			WHERE
			nama LIKE '%$keyword%' OR
			absen LIKE '%$keyword%' OR
			jurusan LIKE '%$keyword%'
			";
	return query($query);
}

function registration($data)
{
	global $conn;

	$username = strtolower(stripslashes($data["username"]));
	$password = mysqli_real_escape_string($conn, $data["password"]);
	$password2 = mysqli_real_escape_string($conn, $data["password2"]);

	// cek username sudah ada atau belum
	$result = mysqli_query($conn, "SELECT username FROM user WHERE username = '$username'");

	if (mysqli_fetch_assoc($result)) {
		echo "<script>
				alert('username sudah terdaftar!')
		      </script>";
		return false;
	}

	// cek konfirmasi password
	if ($password !== $password2) {
		echo "<script>
				alert('konfirmasi password tidak sesuai!');
		      </script>";
		return false;
	}

	// enkripsi password
	$password = password_hash($password, PASSWORD_DEFAULT);

	// tambahkan userbaru ke database
	mysqli_query($conn, "INSERT INTO user (username, password) VALUES('$username', '$password')");

	return mysqli_affected_rows($conn);
}