protomux-rpc-web/dist/index.js

226 lines
6.7 KiB
JavaScript

import EventEmitter from "events";
// @ts-ignore
import Protomux from "protomux";
// @ts-ignore
import c from "compact-encoding";
// @ts-ignore
import bitfield from "compact-encoding-bitfield";
// @ts-ignore
import bits from "bits-to-bytes";
export default class ProtomuxRPC extends EventEmitter {
_id;
_ending;
_error;
_responding;
_requests;
_defaultValueEncoding;
_responders;
_channel;
_request;
_response;
constructor(stream, options = {}) {
super();
this._mux = Protomux.from(stream);
this._defaultValueEncoding = options?.valueEncoding;
this._id = 1;
this._ending = false;
this._responding = 0;
this._requests = new Map();
this._responders = new Map();
this._ready = this._init(options);
}
_mux;
get mux() {
return this._mux;
}
_ready;
get ready() {
return this._ready;
}
get closed() {
return this._channel.closed;
}
get stream() {
return this._mux.stream;
}
async _init(options) {
this._channel = await this._mux.createChannel({
protocol: "protomux-rpc",
id: options?.id,
handshake: options?.handshake
? options?.handshakeEncoding || c.raw
: null,
onopen: this._onopen.bind(this),
onclose: this._onclose.bind(this),
ondestroy: this._ondestroy.bind(this),
});
if (this._channel === null)
throw new Error("duplicate channel");
this._request = await this._channel.addMessage({
encoding: request,
onmessage: this._onrequest.bind(this),
});
this._response = await this._channel.addMessage({
encoding: response,
onmessage: this._onresponse.bind(this),
});
this._channel.open(options?.handshake);
await this._channel.ready;
}
_onopen(handshake) {
this.emit("open", handshake);
}
_onclose() {
const err = this._error || new Error("channel closed");
for (const request of this._requests.values()) {
request.reject(err);
}
this._requests.clear();
this._responders.clear();
this.emit("close");
}
_ondestroy() {
this.emit("destroy");
}
async _onrequest({ id, method, value, }) {
let error = null;
const responder = this._responders.get(method);
if (responder === undefined)
error = `unknown method '${method}'`;
else {
const { valueEncoding = this._defaultValueEncoding, requestEncoding = valueEncoding, responseEncoding = valueEncoding, } = responder.options;
if (requestEncoding)
value = c.decode(requestEncoding, value);
this._responding++;
try {
value = await responder.handler(value);
}
catch (err) {
error = err.message;
}
this._responding--;
if (!error && responseEncoding && id) {
value = c.encode(responseEncoding, value);
}
}
if (id)
this._response.send({ id, error, value });
this._endMaybe();
}
_onresponse({ id, error, value }) {
if (id === 0)
return;
const request = this._requests.get(id);
if (request === undefined)
return;
this._requests.delete(id);
if (error)
request.reject(new Error(error));
else {
const { valueEncoding = this._defaultValueEncoding, responseEncoding = valueEncoding, } = request.options;
if (responseEncoding)
value = c.decode(responseEncoding, value);
request.resolve(value);
}
this._endMaybe();
}
respond(method, options, handler) {
if (typeof options === "function") {
handler = options;
options = {};
}
this._responders.set(method, { options, handler });
return this;
}
unrespond(method) {
this._responders.delete(method);
return this;
}
async request(method, value, options = {}) {
if (this.closed)
throw new Error("channel closed");
const { valueEncoding = this._defaultValueEncoding, requestEncoding = valueEncoding, } = options;
if (requestEncoding)
value = c.encode(requestEncoding, value);
const id = this._id++;
this._request.send({ id, method, value });
return new Promise((resolve, reject) => {
this._requests.set(id, { options, resolve, reject });
});
}
event(method, value, options = {}) {
if (this.closed)
throw new Error("channel closed");
const { valueEncoding = this._defaultValueEncoding, requestEncoding = valueEncoding, } = options;
if (requestEncoding)
value = c.encode(requestEncoding, value);
this._request.send({ id: 0, method, value });
}
cork() {
this._channel.cork();
}
uncork() {
this._channel.uncork();
}
async end() {
this._ending = true;
this._endMaybe();
await EventEmitter.once(this, "close");
}
_endMaybe() {
if (this._ending && this._responding === 0 && this._requests.size === 0) {
this._channel.close();
}
}
destroy(err) {
this._error = err || new Error("channel destroyed");
this._channel.close();
}
}
const request = {
preencode(state, m) {
c.uint.preencode(state, m.id);
c.string.preencode(state, m.method);
c.raw.preencode(state, m.value);
},
encode(state, m) {
c.uint.encode(state, m.id);
c.string.encode(state, m.method);
c.raw.encode(state, m.value);
},
decode(state) {
return {
id: c.uint.decode(state),
method: c.string.decode(state),
value: c.raw.decode(state),
};
},
};
const flags = bitfield(1);
const response = {
preencode(state, m) {
flags.preencode(state);
c.uint.preencode(state, m.id);
if (m.error)
c.string.preencode(state, m.error);
else
c.raw.preencode(state, m.value);
},
encode(state, m) {
flags.encode(state, bits.of(m.error));
c.uint.encode(state, m.id);
if (m.error)
c.string.encode(state, m.error);
else
c.raw.encode(state, m.value);
},
decode(state) {
const [error] = bits.iterator(flags.decode(state));
return {
id: c.uint.decode(state),
error: error ? c.string.decode(state) : null,
value: !error ? c.raw.decode(state) : null,
};
},
};