ethers.js/lib.esm/providers/provider-socket.js
2023-03-27 21:22:35 -04:00

229 lines
7.8 KiB
JavaScript

/**
* Generic long-lived socket provider.
*
* Sub-classing notes
* - a sub-class MUST call the `_start()` method once connected
* - a sub-class MUST override the `_write(string)` method
* - a sub-class MUST call `_processMessage(string)` for each message
*
* @_subsection: api/providers/abstract-provider
*/
import { UnmanagedSubscriber } from "./abstract-provider.js";
import { assert, assertArgument } from "../utils/index.js";
import { JsonRpcApiProvider } from "./provider-jsonrpc.js";
export class SocketSubscriber {
#provider;
#filter;
get filter() { return JSON.parse(this.#filter); }
#filterId;
#paused;
#emitPromise;
constructor(provider, filter) {
this.#provider = provider;
this.#filter = JSON.stringify(filter);
this.#filterId = null;
this.#paused = null;
this.#emitPromise = null;
}
start() {
this.#filterId = this.#provider.send("eth_subscribe", this.filter).then((filterId) => {
;
this.#provider._register(filterId, this);
return filterId;
});
}
stop() {
(this.#filterId).then((filterId) => {
this.#provider.send("eth_unsubscribe", [filterId]);
});
this.#filterId = null;
}
// @TODO: pause should trap the current blockNumber, unsub, and on resume use getLogs
// and resume
pause(dropWhilePaused) {
assert(dropWhilePaused, "preserve logs while paused not supported by SocketSubscriber yet", "UNSUPPORTED_OPERATION", { operation: "pause(false)" });
this.#paused = !!dropWhilePaused;
}
resume() {
this.#paused = null;
}
_handleMessage(message) {
if (this.#filterId == null) {
return;
}
if (this.#paused === null) {
let emitPromise = this.#emitPromise;
if (emitPromise == null) {
emitPromise = this._emit(this.#provider, message);
}
else {
emitPromise = emitPromise.then(async () => {
await this._emit(this.#provider, message);
});
}
this.#emitPromise = emitPromise.then(() => {
if (this.#emitPromise === emitPromise) {
this.#emitPromise = null;
}
});
}
}
async _emit(provider, message) {
throw new Error("sub-classes must implemente this; _emit");
}
}
export class SocketBlockSubscriber extends SocketSubscriber {
constructor(provider) {
super(provider, ["newHeads"]);
}
async _emit(provider, message) {
provider.emit("block", parseInt(message.number));
}
}
export class SocketPendingSubscriber extends SocketSubscriber {
constructor(provider) {
super(provider, ["newPendingTransactions"]);
}
async _emit(provider, message) {
provider.emit("pending", message);
}
}
export class SocketEventSubscriber extends SocketSubscriber {
#logFilter;
get logFilter() { return JSON.parse(this.#logFilter); }
constructor(provider, filter) {
super(provider, ["logs", filter]);
this.#logFilter = JSON.stringify(filter);
}
async _emit(provider, message) {
provider.emit(this.logFilter, provider._wrapLog(message, provider._network));
}
}
/**
* SocketProvider...
*
*/
export class SocketProvider extends JsonRpcApiProvider {
#callbacks;
// Maps each filterId to its subscriber
#subs;
// If any events come in before a subscriber has finished
// registering, queue them
#pending;
constructor(network) {
super(network, { batchMaxCount: 1 });
this.#callbacks = new Map();
this.#subs = new Map();
this.#pending = new Map();
}
// This value is only valid after _start has been called
/*
get _network(): Network {
if (this.#network == null) {
throw new Error("this shouldn't happen");
}
return this.#network.clone();
}
*/
_getSubscriber(sub) {
switch (sub.type) {
case "close":
return new UnmanagedSubscriber("close");
case "block":
return new SocketBlockSubscriber(this);
case "pending":
return new SocketPendingSubscriber(this);
case "event":
return new SocketEventSubscriber(this, sub.filter);
case "orphan":
// Handled auto-matically within AbstractProvider
// when the log.removed = true
if (sub.filter.orphan === "drop-log") {
return new UnmanagedSubscriber("drop-log");
}
}
return super._getSubscriber(sub);
}
_register(filterId, subscriber) {
this.#subs.set(filterId, subscriber);
const pending = this.#pending.get(filterId);
if (pending) {
for (const message of pending) {
subscriber._handleMessage(message);
}
this.#pending.delete(filterId);
}
}
async _send(payload) {
// WebSocket provider doesn't accept batches
assertArgument(!Array.isArray(payload), "WebSocket does not support batch send", "payload", payload);
// @TODO: stringify payloads here and store to prevent mutations
// Prepare a promise to respond to
const promise = new Promise((resolve, reject) => {
this.#callbacks.set(payload.id, { payload, resolve, reject });
});
// Wait until the socket is connected before writing to it
await this._waitUntilReady();
// Write the request to the socket
await this._write(JSON.stringify(payload));
return [await promise];
}
// Sub-classes must call this once they are connected
/*
async _start(): Promise<void> {
if (this.#ready) { return; }
for (const { payload } of this.#callbacks.values()) {
await this._write(JSON.stringify(payload));
}
this.#ready = (async function() {
await super._start();
})();
}
*/
// Sub-classes must call this for each message
async _processMessage(message) {
const result = (JSON.parse(message));
if ("id" in result) {
const callback = this.#callbacks.get(result.id);
if (callback == null) {
console.log("Weird... Response for not a thing we sent");
return;
}
this.#callbacks.delete(result.id);
callback.resolve(result);
/*
if ("error" in result) {
const { message, code, data } = result.error;
const error = makeError(message || "unkonwn error", "SERVER_ERROR", {
request: `ws:${ JSON.stringify(callback.payload) }`,
info: { code, data }
});
callback.reject(error);
} else {
callback.resolve(result.result);
}
*/
}
else if (result.method === "eth_subscription") {
const filterId = result.params.subscription;
const subscriber = this.#subs.get(filterId);
if (subscriber) {
subscriber._handleMessage(result.params.result);
}
else {
let pending = this.#pending.get(filterId);
if (pending == null) {
pending = [];
this.#pending.set(filterId, pending);
}
pending.push(result.params.result);
}
}
}
async _write(message) {
throw new Error("sub-classes must override this");
}
}
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