anyTV/anytv-node-quota

'use strict';

module.exports = function (store, service = 'default', log_request = false) {
    // create middleware
    return (req, res, next) => {


        function start() {
            let access_token = get_bearer_token(req);

            // if no access_token return error
            if (!access_token.length) {
                return res.status(400)
                        .send({error: 'No access token.'})
            }

            store.get_client_id(access_token, check_limit)
        }

        function check_limit(err, client_id) {
            if (err) {
                return res.status(400)
                        .send({error: err})
            }

            store.exceed_limit(client_id, service, (err, exceeded) => {
                if (err) {
                    return res.status(500)
                            .send({error: err})
                }

                if (exceeded) {
                    return res.status(400)
                            .send({error: 'Quota exceeded.'})
                }

                bind_quota(client_id)
            })
        }

        function bind_quota(client_id) {
            // save original res.send
            let orig_send = res.send
            let orig_json = res.json

            res.anytv_quota = {
                weight: 0,
                client: {
                    id: null,
                    secret: null,
                    token: null
                },
                set_weight: (weight = 0) => {
                    res.anytv_quota.weight = weight

                    return res;
                }
            }

            res.send = function (data) {
                let weight = res.anytv_quota.weight

                clean_up()
                res.send(data)

                // increment_usage
                store.increment_usage(client_id, service, weight)

                // log request
                if (log_request) {
                    store.log_request(client_id, service, weight, req.path)
                }
            }


            res.json = function (data) {
                let weight = res.anytv_quota.weight

                clean_up()
                res.json(data)

                // increment_usage
                store.increment_usage(client_id,  service, weight)

                // log request
                if (log_request) {
                    store.log_request(client_id, service, weight, req.path)
                }
            }

            function clean_up() {
                res.json = orig_json
                res.send = orig_send
            }


            next()
        }

        function get_bearer_token (req) {
            let header_token = req.get('Authorization');
            let get_token = req.query.access_token;
            let post_token = req.body ? req.body.access_token : undefined;

            let method_used = (header_token !== undefined) + (get_token !== undefined) + (post_token !== undefined);

            if (method_used === 0) {
                return '';
            }

            // Header: http://tools.ietf.org/html/rfc6750#section-2.1
            if (header_token) {
                var matches = header_token.match(/Bearer\s(\S+)/);

                if (!matches) {
                    return '';
                }

                header_token = matches[1];
            }

            return header_token || post_token || get_token;
        }

        start()
    }
}