114 lines
2.1 KiB
JavaScript
114 lines
2.1 KiB
JavaScript
import schemapack from 'schemapack';
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import {compose} from '@avocado/core';
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import {EventEmitter} from '@avocado/mixins';
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import {allPackets, idFromPacket, packetFromId} from './registry';
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/**
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* Packet types (see https://github.com/socketio/socket.io-protocol)
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*/
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const TYPES = {
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EVENT: 2,
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ERROR: 4,
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BINARY_EVENT: 5,
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};
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const errorPacket = {
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type: TYPES.ERROR,
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data: 'parser error',
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};
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let schemas = undefined;
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function schemaFromId(id) {
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if (!schemas) {
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schemas = {};
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for (const Packet of allPackets()) {
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const id_ = idFromPacket(Packet);
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schemas[id_] = schemapack.build(Packet.schema);
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}
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}
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return schemas[id];
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}
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class Encoder {
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encode(packet, callback) {
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switch (packet.type) {
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case TYPES.EVENT:
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case TYPES.BINARY_EVENT:
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return callback([this.pack(packet)]);
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default:
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return callback([JSON.stringify(packet)]);
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}
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}
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pack(packet) {
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const eventId = packet.data[0];
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const schema = schemaFromId(eventId);
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if (!schema) {
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throw new Error('unknown schema with id: ' + eventId);
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}
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return schema.encode({
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_id: eventId,
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data: packet.data[1],
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});
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}
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}
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const decorateDecoder = compose(
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EventEmitter,
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);
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class Decoder extends decorateDecoder(class {}) {
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add(obj) {
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if (typeof obj === 'string') {
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this.parseJSON(obj);
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}
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else {
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this.parseBinary(obj);
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}
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}
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destroy() {}
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parseBinary(obj) {
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const view = new Uint8Array(obj);
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const packetId = view[0];
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let packet;
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try {
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const schema = schemaFromId(packetId);
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if (!schema) {
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throw new Error(`unknown schema with id: ${packetId}`);
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}
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const {data} = schema.decode(obj);
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const Packet = packetFromId(packetId);
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packet = {
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type: TYPES.EVENT,
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data: [packetId, new Packet(data)],
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nsp: '/',
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};
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}
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catch (e) {
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packet = errorPacket;
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}
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this.emit('decoded', packet);
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}
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parseJSON(obj) {
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let decoded;
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try {
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decoded = JSON.parse(obj);
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}
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catch (e) {
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decoded = errorPacket;
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}
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this.emit('decoded', decoded);
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}
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}
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export {Decoder, Encoder};
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