Packet.vala

/**
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * AUTHORS
 * Maciek Borzecki <maciek.borzecki (at] gmail.com>
 * gyan000 <gyan000 (at] ijaz.fr>
 */

using Json;

public errordomain PacketError {
    MALFORMED
}

namespace MConnect {

    public class Packet : GLib.Object {

        public const int PROTOCOL_VERSION = 7;
        public const string IDENTITY = "kdeconnect.identity";
        public const string PAIR = "kdeconnect.pair";
        public const string ENCRYPTED = "kdeconnect.encrypted";

        /**
         * Payload:
         * Wrapper for payload transfer information
         */
        public struct Payload {
            public uint64 size;
            public uint port;
        }
        public string pkt_type {
            get; private set; default = "";
        }
        public int64 id {
            get; private set; default = 0;
        }
        public Json.Object body {
            get; private set; default = null;
        }
        public Packet.Payload ? payload {
            get; set; default = null;
        }

        public Packet (string type, Json.Object body, int64 id = 0) {
            this.pkt_type = type;
            this.body = body;
            if (id == 0) {
                this.id = get_real_time () / 1000;
            } else {
                this.id = id;
            }
        }

        public static Packet ? new_from_data (string data) {
            Json.Parser jp = new Json.Parser ();

            try {
                jp.load_from_data (data, -1);
                // There should be an object at root node
                Json.Object root_obj = jp.get_root ().get_object ();
                if (root_obj == null)
                    throw new PacketError.MALFORMED ("Missing root object");

                // Object needs to have these fields
                string[] required_members = { "type", "id", "body" };
                foreach (string m in required_members) {
                    if (root_obj.has_member (m) == false)
                        throw new PacketError.MALFORMED (@"Missing $m member");
                }

                string type = root_obj.get_string_member ("type");
                int64 id = root_obj.get_int_member ("id");
                Json.Object body = root_obj.get_object_member ("body");

                debug ("Packet type: %s", type);

                var pkt = new Packet (type, body, id);

                // ignore payload info for encrypted packets
                if (type != ENCRYPTED) {
                    if (root_obj.has_member ("payloadSize") &&
                        root_obj.has_member ("payloadTransferInfo")) {


                        var size = root_obj.get_int_member ("payloadSize");

                        var pti = root_obj.get_object_member ("payloadTransferInfo");
                        int64 port = 0;
                        if (pti == null) {
                            warning ("No payload transfer info?");
                        } else {
                            port = (int) pti.get_int_member ("port");
                        }

                        if (size != 0 && port != 0) {
                            pkt.payload = { (uint64) size, (uint) port };
                        }
                    }
                }

                return pkt;
            } catch (Error e) {
                message ("Failed to parse message: \'%s\', error: %s", data, e.message);
            }
            return null;
        }

        public static Packet new_pair (bool pair = true) {
            var builder = new Json.Builder ();
            builder.begin_object ();
            builder.set_member_name ("pair");
            builder.add_boolean_value (pair);
            builder.end_object ();

            var data_obj = builder.get_root ().get_object ();

            return new Packet (PAIR, data_obj);
        }

        public static Packet new_identity (string name,
                                           string device_id,
                                           string[] in_interfaces,
                                           string[] out_interfaces,
                                           string device_type = "desktop") {
            var builder = new Json.Builder ();
            builder.begin_object ();
            builder.set_member_name ("deviceName");
            builder.add_string_value (name);
            builder.set_member_name ("deviceId");
            builder.add_string_value (device_id);
            builder.set_member_name ("deviceType");
            builder.add_string_value (device_type);
            builder.set_member_name ("SupportedIncomingInterfaces");
            builder.add_string_value (string.joinv (",", in_interfaces));
            builder.set_member_name ("SupportedOutgoingInterfaces");
            builder.add_string_value (string.joinv (",", out_interfaces));
            builder.set_member_name ("protocolVersion");
            builder.add_int_value (PROTOCOL_VERSION);
            builder.end_object ();

            Json.Object data_obj = builder.get_root ().get_object ();

            return new Packet (IDENTITY, data_obj);
        }

        public string to_string (bool pretty_format = false) {
            var gen = new Json.Generator ();
            var root = new Json.Node (Json.NodeType.OBJECT);
            var root_obj = new Json.Object ();
            root_obj.set_string_member ("type", pkt_type);
            root_obj.set_int_member ("id", id);
            root_obj.set_object_member ("body", body);
            if (this.payload != null) {
                root_obj.set_int_member ("payloadSize", (int64) this.payload.size);
                var pti = new Json.Object ();
                pti.set_int_member ("port", this.payload.port);
                root_obj.set_object_member ("payloadTransferInfo", pti);
            }
            root.set_object (root_obj);
            gen.set_root (root);
            gen.set_pretty (pretty_format);
            return gen.to_data (null);;
        }
    }
}