File size: 7,616 Bytes
c212805 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 | export default class Serializer {
constructor(allowedMetadataKeys) {
this.HEADER_LENGTH = 1;
this.USER_BROADCAST_PUSH_META_LENGTH = 6;
this.KINDS = { userBroadcastPush: 3, userBroadcast: 4 };
this.BINARY_ENCODING = 0;
this.JSON_ENCODING = 1;
this.BROADCAST_EVENT = 'broadcast';
this.allowedMetadataKeys = [];
this.allowedMetadataKeys = allowedMetadataKeys !== null && allowedMetadataKeys !== void 0 ? allowedMetadataKeys : [];
}
encode(msg, callback) {
if (msg.event === this.BROADCAST_EVENT &&
!(msg.payload instanceof ArrayBuffer) &&
typeof msg.payload.event === 'string') {
return callback(this._binaryEncodeUserBroadcastPush(msg));
}
let payload = [msg.join_ref, msg.ref, msg.topic, msg.event, msg.payload];
return callback(JSON.stringify(payload));
}
_binaryEncodeUserBroadcastPush(message) {
var _a;
if (this._isArrayBuffer((_a = message.payload) === null || _a === void 0 ? void 0 : _a.payload)) {
return this._encodeBinaryUserBroadcastPush(message);
}
else {
return this._encodeJsonUserBroadcastPush(message);
}
}
_encodeBinaryUserBroadcastPush(message) {
var _a, _b;
const userPayload = (_b = (_a = message.payload) === null || _a === void 0 ? void 0 : _a.payload) !== null && _b !== void 0 ? _b : new ArrayBuffer(0);
return this._encodeUserBroadcastPush(message, this.BINARY_ENCODING, userPayload);
}
_encodeJsonUserBroadcastPush(message) {
var _a, _b;
const userPayload = (_b = (_a = message.payload) === null || _a === void 0 ? void 0 : _a.payload) !== null && _b !== void 0 ? _b : {};
const encoder = new TextEncoder();
const encodedUserPayload = encoder.encode(JSON.stringify(userPayload)).buffer;
return this._encodeUserBroadcastPush(message, this.JSON_ENCODING, encodedUserPayload);
}
_encodeUserBroadcastPush(message, encodingType, encodedPayload) {
var _a, _b;
// Encode each header field as UTF-8. The length prefixes are byte counts and
// the decode side uses TextDecoder (UTF-8), so measuring with String.length
// and writing with charCodeAt would corrupt any multi-byte character (e.g.
// accents or emoji) and desynchronize the buffer.
const encoder = new TextEncoder();
const topic = encoder.encode(message.topic);
const ref = encoder.encode((_a = message.ref) !== null && _a !== void 0 ? _a : '');
const joinRef = encoder.encode((_b = message.join_ref) !== null && _b !== void 0 ? _b : '');
const userEvent = encoder.encode(message.payload.event);
// Filter metadata based on allowed keys
const rest = this.allowedMetadataKeys
? this._pick(message.payload, this.allowedMetadataKeys)
: {};
const metadata = encoder.encode(Object.keys(rest).length === 0 ? '' : JSON.stringify(rest));
// Validate byte lengths don't exceed uint8 max value (255)
if (joinRef.length > 255) {
throw new Error(`joinRef length ${joinRef.length} exceeds maximum of 255`);
}
if (ref.length > 255) {
throw new Error(`ref length ${ref.length} exceeds maximum of 255`);
}
if (topic.length > 255) {
throw new Error(`topic length ${topic.length} exceeds maximum of 255`);
}
if (userEvent.length > 255) {
throw new Error(`userEvent length ${userEvent.length} exceeds maximum of 255`);
}
if (metadata.length > 255) {
throw new Error(`metadata length ${metadata.length} exceeds maximum of 255`);
}
const metaLength = this.USER_BROADCAST_PUSH_META_LENGTH +
joinRef.length +
ref.length +
topic.length +
userEvent.length +
metadata.length;
const header = new ArrayBuffer(this.HEADER_LENGTH + metaLength);
const view = new DataView(header);
const bytes = new Uint8Array(header);
let offset = 0;
view.setUint8(offset++, this.KINDS.userBroadcastPush); // kind
view.setUint8(offset++, joinRef.length);
view.setUint8(offset++, ref.length);
view.setUint8(offset++, topic.length);
view.setUint8(offset++, userEvent.length);
view.setUint8(offset++, metadata.length);
view.setUint8(offset++, encodingType);
bytes.set(joinRef, offset);
offset += joinRef.length;
bytes.set(ref, offset);
offset += ref.length;
bytes.set(topic, offset);
offset += topic.length;
bytes.set(userEvent, offset);
offset += userEvent.length;
bytes.set(metadata, offset);
offset += metadata.length;
var combined = new Uint8Array(header.byteLength + encodedPayload.byteLength);
combined.set(new Uint8Array(header), 0);
combined.set(new Uint8Array(encodedPayload), header.byteLength);
return combined.buffer;
}
decode(rawPayload, callback) {
if (this._isArrayBuffer(rawPayload)) {
let result = this._binaryDecode(rawPayload);
return callback(result);
}
if (typeof rawPayload === 'string') {
const jsonPayload = JSON.parse(rawPayload);
const [join_ref, ref, topic, event, payload] = jsonPayload;
return callback({ join_ref, ref, topic, event, payload });
}
return callback({});
}
_binaryDecode(buffer) {
const view = new DataView(buffer);
const kind = view.getUint8(0);
const decoder = new TextDecoder();
switch (kind) {
case this.KINDS.userBroadcast:
return this._decodeUserBroadcast(buffer, view, decoder);
}
}
_decodeUserBroadcast(buffer, view, decoder) {
const topicSize = view.getUint8(1);
const userEventSize = view.getUint8(2);
const metadataSize = view.getUint8(3);
const payloadEncoding = view.getUint8(4);
let offset = this.HEADER_LENGTH + 4;
const topic = decoder.decode(buffer.slice(offset, offset + topicSize));
offset = offset + topicSize;
const userEvent = decoder.decode(buffer.slice(offset, offset + userEventSize));
offset = offset + userEventSize;
const metadata = decoder.decode(buffer.slice(offset, offset + metadataSize));
offset = offset + metadataSize;
const payload = buffer.slice(offset, buffer.byteLength);
const parsedPayload = payloadEncoding === this.JSON_ENCODING ? JSON.parse(decoder.decode(payload)) : payload;
const data = {
type: this.BROADCAST_EVENT,
event: userEvent,
payload: parsedPayload,
};
// Metadata is optional and always JSON encoded
if (metadataSize > 0) {
data['meta'] = JSON.parse(metadata);
}
return { join_ref: null, ref: null, topic: topic, event: this.BROADCAST_EVENT, payload: data };
}
_isArrayBuffer(buffer) {
var _a;
return buffer instanceof ArrayBuffer || ((_a = buffer === null || buffer === void 0 ? void 0 : buffer.constructor) === null || _a === void 0 ? void 0 : _a.name) === 'ArrayBuffer';
}
_pick(obj, keys) {
if (!obj || typeof obj !== 'object') {
return {};
}
return Object.fromEntries(Object.entries(obj).filter(([key]) => keys.includes(key)));
}
}
//# sourceMappingURL=serializer.js.map |