@supabase/realtime-js
Version:
Listen to realtime updates to your PostgreSQL database
155 lines • 7.29 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
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;
const topic = message.topic;
const ref = (_a = message.ref) !== null && _a !== void 0 ? _a : '';
const joinRef = (_b = message.join_ref) !== null && _b !== void 0 ? _b : '';
const userEvent = message.payload.event;
// Filter metadata based on allowed keys
const rest = this.allowedMetadataKeys
? this._pick(message.payload, this.allowedMetadataKeys)
: {};
const metadata = Object.keys(rest).length === 0 ? '' : JSON.stringify(rest);
// Validate 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);
let view = new DataView(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);
Array.from(joinRef, (char) => view.setUint8(offset++, char.charCodeAt(0)));
Array.from(ref, (char) => view.setUint8(offset++, char.charCodeAt(0)));
Array.from(topic, (char) => view.setUint8(offset++, char.charCodeAt(0)));
Array.from(userEvent, (char) => view.setUint8(offset++, char.charCodeAt(0)));
Array.from(metadata, (char) => view.setUint8(offset++, char.charCodeAt(0)));
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)));
}
}
exports.default = Serializer;
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