rest api.php with pagination code

<?php
$method = $_SERVER['REQUEST_METHOD'];
$request = isset($_GET['request']) ? $_GET['request'] : "";
$uri = explode("/", $request);
$api = isset($uri[0]) ? $uri[0] : "";
$id = isset($uri[1]) ? intval($uri[1]) : 0;
$dbh = new PDO("mysql:host=localhost; dbname=restful; charset=utf8","root","");
$listperpage = 10;

if( $api == "friend" ) {

    if( $method == "GET" ) {
        $page = isset($_GET['page']) ? intval($_GET['page']) : 1;
        if( ! $page ) $page = 1;
        $start = ($page - 1) * $listperpage;

        $sql = "SELECT * FROM friends";
        if( $id ) $sql .= " WHERE id={$id}";
        if( ! $id ) $sql .= " LIMIT {$start}, {$listperpage}";
        if( $res = $dbh->query($sql) ) {
            $friends = $res->fetchAll(PDO::FETCH_ASSOC);
            echo json_encode($friends);
        }

    } elseif ($method == "POST") {

        $result = array("success"=>"false", "count"=>0);
        $name = isset($_POST['name']) ? $_POST['name'] : "";
        $city = isset($_POST['city']) ? $_POST['city'] : "";
        $phone = isset($_POST['phone']) ? $_POST['phone'] : "";
        $email = isset($_POST['email']) ? $_POST['email'] : "";
        if( $name && $city && $phone && $email ) {
            $sql = "INSERT INTO friends(name, city, phone, email) ";
            $sql .= " VALUES('{$name}','{$city}','{$phone}','{$email}')";
            if( $res = $dbh->query($sql) ) {
                $count = $res->rowCount();
                if( $count ) {
                    $result['success'] = "true";
                    $result['count'] = $count;
                }
            }
        }

        echo json_encode($result);

    } elseif ($method == "PUT") {

        $result = array("success"=>"false", "count"=>0);

        if( $id ) {

            $putData = file_get_contents("php://input");
            $data = array();
            parse_str($putData, $data);
            if( $data['name'] && $data['city'] && $data['phone'] && $data['email'] ) {
                $sql = "UPDATE friends SET ";
                $sql .= " name='{$data['name']}' ";
                $sql .= ", city='{$data['city']}' ";
                $sql .= ", phone='{$data['phone']}' ";
                $sql .= ", email='{$data['email']}' ";
                $sql .= " WHERE id={$id}";
                if( $res = $dbh->query($sql) ) {
                    $count = $res->rowCount();
                    if( $count ) {
                        $result['success'] = "true";
                        $result['count'] = $count;
                    }
                }
            }
        }

        echo json_encode($result);

    } elseif ($method == "DELETE") {

        $result = array("success"=>"false", "count"=>0);
        if( $id ) {
            $sql = "DELETE FROM friends WHERE id={$id}";
            if( $res = $dbh->query($sql) ) {
                $count = $res->rowCount();
                if( $count ) {
                    $result['success'] = "true";
                    $result['count'] = $count;
                }
            }
        }
        echo json_encode($result);

    }

} elseif( $api == "pages" ) {

    if( $method == "GET" ) {
        $pages = 0;
        $total = 0;
        $sql = "SELECT count(*) as cnt FROM friends";
        if( $res = $dbh->query($sql) ) {
            $data = $res->fetch();
            $total = $data['cnt'];
        }
        if( $total) {
            $pages = ceil($total/$listperpage);
        }
        $result = array("total"=>$total, "pages"=>$pages);
        echo json_encode($result);
    }

}