ethers.js/src.ts/utils/fetch.ts
2023-02-04 08:25:15 -05:00

893 lines
29 KiB
TypeScript

/**
* Explain fetching here...
*
* @_section api/utils/fetching:Fetching Web Content [about-fetch]
*/
import { decodeBase64, encodeBase64 } from "./base64.js";
import { hexlify } from "./data.js";
import { assert, assertArgument } from "./errors.js";
import { defineProperties } from "./properties.js";
import { toUtf8Bytes, toUtf8String } from "./utf8.js"
import { getUrl } from "./geturl.js";
export type GetUrlResponse = {
statusCode: number,
statusMessage: string,
headers: Record<string, string>,
body: null | Uint8Array
};
export type FetchThrottleParams = {
maxAttempts?: number;
slotInterval?: number;
};
/**
* Called before any network request, allowing updated headers (e.g. Bearer tokens), etc.
*/
export type FetchPreflightFunc = (req: FetchRequest) => Promise<FetchRequest>;
/**
* Called on the response, allowing client-based throttling logic or post-processing.
*/
export type FetchProcessFunc = (req: FetchRequest, resp: FetchResponse) => Promise<FetchResponse>;
/**
* Called prior to each retry; return true to retry, false to abort.
*/
export type FetchRetryFunc = (req: FetchRequest, resp: FetchResponse, attempt: number) => Promise<boolean>;
/**
* Called on Gateway URLs.
*/
export type FetchGatewayFunc = (url: string, signal?: FetchCancelSignal) => Promise<FetchRequest | FetchResponse>;
/**
* Used to perform a fetch; use this to override the underlying network
* fetch layer. In NodeJS, the default uses the "http" and "https" libraries
* and in the browser ``fetch`` is used. If you wish to use Axios, this is
* how you would register it.
*/
export type FetchGetUrlFunc = (req: FetchRequest, signal?: FetchCancelSignal) => Promise<GetUrlResponse>;
const MAX_ATTEMPTS = 12;
const SLOT_INTERVAL = 250;
// The global FetchGetUrlFunc implementation.
let getUrlFunc: FetchGetUrlFunc = getUrl;
const reData = new RegExp("^data:([^;:]*)?(;base64)?,(.*)$", "i");
const reIpfs = new RegExp("^ipfs:/\/(ipfs/)?(.*)$", "i");
// If locked, new Gateways cannot be added
let locked = false;
// https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URLs
async function dataGatewayFunc(url: string, signal?: FetchCancelSignal): Promise<FetchResponse> {
try {
const match = url.match(reData);
if (!match) { throw new Error("invalid data"); }
return new FetchResponse(200, "OK", {
"content-type": (match[1] || "text/plain"),
}, (match[2] ? decodeBase64(match[3]): unpercent(match[3])));
} catch (error) {
return new FetchResponse(599, "BAD REQUEST (invalid data: URI)", { }, null, new FetchRequest(url));
}
}
/**
* Returns a [[FetchGatewayFunc]] for fetching content from a standard
* IPFS gateway hosted at %%baseUrl%%.
*/
function getIpfsGatewayFunc(baseUrl: string): FetchGatewayFunc {
async function gatewayIpfs(url: string, signal?: FetchCancelSignal): Promise<FetchRequest | FetchResponse> {
try {
const match = url.match(reIpfs);
if (!match) { throw new Error("invalid link"); }
return new FetchRequest(`${ baseUrl }${ match[2] }`);
} catch (error) {
return new FetchResponse(599, "BAD REQUEST (invalid IPFS URI)", { }, null, new FetchRequest(url));
}
}
return gatewayIpfs;
}
const Gateways: Record<string, FetchGatewayFunc> = {
"data": dataGatewayFunc,
"ipfs": getIpfsGatewayFunc("https:/\/gateway.ipfs.io/ipfs/")
};
const fetchSignals: WeakMap<FetchRequest, () => void> = new WeakMap();
/**
* @_ignore
*/
export class FetchCancelSignal {
#listeners: Array<() => void>;
#cancelled: boolean;
constructor(request: FetchRequest) {
this.#listeners = [ ];
this.#cancelled = false;
fetchSignals.set(request, () => {
if (this.#cancelled) { return; }
this.#cancelled = true;
for (const listener of this.#listeners) {
setTimeout(() => { listener(); }, 0);
}
this.#listeners = [ ];
});
}
addListener(listener: () => void): void {
assert(!this.#cancelled, "singal already cancelled", "UNSUPPORTED_OPERATION", {
operation: "fetchCancelSignal.addCancelListener"
});
this.#listeners.push(listener);
}
get cancelled(): boolean { return this.#cancelled; }
checkSignal(): void {
assert(!this.cancelled, "cancelled", "CANCELLED", { });
}
}
// Check the signal, throwing if it is cancelled
function checkSignal(signal?: FetchCancelSignal): FetchCancelSignal {
if (signal == null) { throw new Error("missing signal; should not happen"); }
signal.checkSignal();
return signal;
}
/**
* Represents a request for a resource using a URI.
*
* By default, the supported schemes are ``HTTP``, ``HTTPS``, ``data:``,
* and ``IPFS:``.
*
* Additional schemes can be added globally using [[registerGateway]].
*
* @example:
* req = new FetchRequest("https://www.ricmoo.com")
* resp = await req.send()
* resp.body.length
* //_result:
*/
export class FetchRequest implements Iterable<[ key: string, value: string ]> {
#allowInsecure: boolean;
#gzip: boolean;
#headers: Record<string, string>;
#method: string;
#timeout: number;
#url: string;
#body?: Uint8Array;
#bodyType?: string;
#creds?: string;
// Hooks
#preflight?: null | FetchPreflightFunc;
#process?: null | FetchProcessFunc;
#retry?: null | FetchRetryFunc;
#signal?: FetchCancelSignal;
#throttle: Required<FetchThrottleParams>;
/**
* The fetch URI to requrest.
*/
get url(): string { return this.#url; }
set url(url: string) {
this.#url = String(url);
}
/**
* The fetch body, if any, to send as the request body. //(default: null)//
*
* When setting a body, the intrinsic ``Content-Type`` is automatically
* set and will be used if **not overridden** by setting a custom
* header.
*
* If %%body%% is null, the body is cleared (along with the
* intrinsic ``Content-Type``) and the .
*
* If %%body%% is a string, the intrincis ``Content-Type`` is set to
* ``text/plain``.
*
* If %%body%% is a Uint8Array, the intrincis ``Content-Type`` is set to
* ``application/octet-stream``.
*
* If %%body%% is any other object, the intrincis ``Content-Type`` is
* set to ``application/json``.
*/
get body(): null | Uint8Array {
if (this.#body == null) { return null; }
return new Uint8Array(this.#body);
}
set body(body: null | string | Readonly<object> | Readonly<Uint8Array>) {
if (body == null) {
this.#body = undefined;
this.#bodyType = undefined;
} else if (typeof(body) === "string") {
this.#body = toUtf8Bytes(body);
this.#bodyType = "text/plain";
} else if (body instanceof Uint8Array) {
this.#body = body;
this.#bodyType = "application/octet-stream";
} else if (typeof(body) === "object") {
this.#body = toUtf8Bytes(JSON.stringify(body));
this.#bodyType = "application/json";
} else {
throw new Error("invalid body");
}
}
/**
* Returns true if the request has a body.
*/
hasBody(): this is (FetchRequest & { body: Uint8Array }) {
return (this.#body != null);
}
/**
* The HTTP method to use when requesting the URI. If no method
* has been explicitly set, then ``GET`` is used if the body is
* null and ``POST`` otherwise.
*/
get method(): string {
if (this.#method) { return this.#method; }
if (this.hasBody()) { return "POST"; }
return "GET";
}
set method(method: null | string) {
if (method == null) { method = ""; }
this.#method = String(method).toUpperCase();
}
/**
* The headers that will be used when requesting the URI. All
* keys are lower-case.
*
* This object is a copy, so any chnages will **NOT** be reflected
* in the ``FetchRequest``.
*
* To set a header entry, use the ``setHeader`` method.
*/
get headers(): Record<string, string> {
const headers = Object.assign({ }, this.#headers);
if (this.#creds) {
headers["authorization"] = `Basic ${ encodeBase64(toUtf8Bytes(this.#creds)) }`;
};
if (this.allowGzip) {
headers["accept-encoding"] = "gzip";
}
if (headers["content-type"] == null && this.#bodyType) {
headers["content-type"] = this.#bodyType;
}
if (this.body) { headers["content-length"] = String(this.body.length); }
return headers;
}
/**
* Get the header for %%key%%, ignoring case.
*/
getHeader(key: string): string {
return this.headers[key.toLowerCase()];
}
/**
* Set the header for %%key%% to %%value%%. All values are coerced
* to a string.
*/
setHeader(key: string, value: string | number): void {
this.#headers[String(key).toLowerCase()] = String(value);
}
/**
* Clear all headers, resetting all intrinsic headers.
*/
clearHeaders(): void {
this.#headers = { };
}
[Symbol.iterator](): Iterator<[ key: string, value: string ]> {
const headers = this.headers;
const keys = Object.keys(headers);
let index = 0;
return {
next: () => {
if (index < keys.length) {
const key = keys[index++];
return {
value: [ key, headers[key] ], done: false
}
}
return { value: undefined, done: true };
}
};
}
/**
* The value that will be sent for the ``Authorization`` header.
*
* To set the credentials, use the ``setCredentials`` method.
*/
get credentials(): null | string {
return this.#creds || null;
}
/**
* Sets an ``Authorization`` for %%username%% with %%password%%.
*/
setCredentials(username: string, password: string): void {
assertArgument(!username.match(/:/), "invalid basic authentication username", "username", "[REDACTED]");
this.#creds = `${ username }:${ password }`;
}
/**
* Enable and request gzip-encoded responses. The response will
* automatically be decompressed. //(default: true)//
*/
get allowGzip(): boolean {
return this.#gzip;
}
set allowGzip(value: boolean) {
this.#gzip = !!value;
}
/**
* Allow ``Authentication`` credentials to be sent over insecure
* channels. //(default: false)//
*/
get allowInsecureAuthentication(): boolean {
return !!this.#allowInsecure;
}
set allowInsecureAuthentication(value: boolean) {
this.#allowInsecure = !!value;
}
/**
* The timeout (in milliseconds) to wait for a complere response.
* //(default: 5 minutes)//
*/
get timeout(): number { return this.#timeout; }
set timeout(timeout: number) {
assertArgument(timeout >= 0, "timeout must be non-zero", "timeout", timeout);
this.#timeout = timeout;
}
/**
* This function is called prior to each request, for example
* during a redirection or retry in case of server throttling.
*
* This offers an opportunity to populate headers or update
* content before sending a request.
*/
get preflightFunc(): null | FetchPreflightFunc {
return this.#preflight || null;
}
set preflightFunc(preflight: null | FetchPreflightFunc) {
this.#preflight = preflight;
}
/**
* This function is called after each response, offering an
* opportunity to provide client-level throttling or updating
* response data.
*
* Any error thrown in this causes the ``send()`` to throw.
*
* To schedule a retry attempt (assuming the maximum retry limit
* has not been reached), use [[response.throwThrottleError]].
*/
get processFunc(): null | FetchProcessFunc {
return this.#process || null;
}
set processFunc(process: null | FetchProcessFunc) {
this.#process = process;
}
/**
* This function is called on each retry attempt.
*/
get retryFunc(): null | FetchRetryFunc {
return this.#retry || null;
}
set retryFunc(retry: null | FetchRetryFunc) {
this.#retry = retry;
}
/**
* Create a new FetchRequest instance with default values.
*
* Once created, each property may be set before issuing a
* ``.send()`` to make teh request.
*/
constructor(url: string) {
this.#url = String(url);
this.#allowInsecure = false;
this.#gzip = true;
this.#headers = { };
this.#method = "";
this.#timeout = 300000;
this.#throttle = {
slotInterval: SLOT_INTERVAL,
maxAttempts: MAX_ATTEMPTS
};
}
toString(): string {
return `<FetchRequest method=${ JSON.stringify(this.method) } url=${ JSON.stringify(this.url) } headers=${ JSON.stringify(this.headers) } body=${ this.#body ? hexlify(this.#body): "null" }>`;
}
/**
* Update the throttle parameters used to determine maximum
* attempts and exponential-backoff properties.
*/
setThrottleParams(params: FetchThrottleParams): void {
if (params.slotInterval != null) {
this.#throttle.slotInterval = params.slotInterval;
}
if (params.maxAttempts != null) {
this.#throttle.maxAttempts = params.maxAttempts;
}
}
async #send(attempt: number, expires: number, delay: number, _request: FetchRequest, _response: FetchResponse): Promise<FetchResponse> {
if (attempt >= this.#throttle.maxAttempts) {
return _response.makeServerError("exceeded maximum retry limit");
}
assert(getTime() <= expires, "timeout", "TIMEOUT", {
operation: "request.send", reason: "timeout", request: _request
});
if (delay > 0) { await wait(delay); }
let req = this.clone();
const scheme = (req.url.split(":")[0] || "").toLowerCase();
// Process any Gateways
if (scheme in Gateways) {
const result = await Gateways[scheme](req.url, checkSignal(_request.#signal));
if (result instanceof FetchResponse) {
let response = result;
if (this.processFunc) {
checkSignal(_request.#signal);
try {
response = await this.processFunc(req, response);
} catch (error: any) {
// Something went wrong during processing; throw a 5xx server error
if (error.throttle == null || typeof(error.stall) !== "number") {
response.makeServerError("error in post-processing function", error).assertOk();
}
// Ignore throttling
}
}
return response;
}
req = result;
}
// We have a preflight function; update the request
if (this.preflightFunc) { req = await this.preflightFunc(req); }
const resp = await getUrlFunc(req, checkSignal(_request.#signal));
let response = new FetchResponse(resp.statusCode, resp.statusMessage, resp.headers, resp.body, _request);
if (response.statusCode === 301 || response.statusCode === 302) {
// Redirect
try {
const location = response.headers.location || "";
return req.redirect(location).#send(attempt + 1, expires, 0, _request, response);
} catch (error) { }
// Things won't get any better on another attempt; abort
return response;
} else if (response.statusCode === 429) {
// Throttle
if (this.retryFunc == null || (await this.retryFunc(req, response, attempt))) {
const retryAfter = response.headers["retry-after"];
let delay = this.#throttle.slotInterval * Math.trunc(Math.random() * Math.pow(2, attempt));
if (typeof(retryAfter) === "string" && retryAfter.match(/^[1-9][0-9]*$/)) {
delay = parseInt(retryAfter);
}
return req.clone().#send(attempt + 1, expires, delay, _request, response);
}
}
if (this.processFunc) {
checkSignal(_request.#signal);
try {
response = await this.processFunc(req, response);
} catch (error: any) {
// Something went wrong during processing; throw a 5xx server error
if (error.throttle == null || typeof(error.stall) !== "number") {
response.makeServerError("error in post-processing function", error).assertOk();
}
// Throttle
let delay = this.#throttle.slotInterval * Math.trunc(Math.random() * Math.pow(2, attempt));;
if (error.stall >= 0) { delay = error.stall; }
return req.clone().#send(attempt + 1, expires, delay, _request, response);
}
}
return response;
}
/**
* Resolves to the response by sending the request.
*/
send(): Promise<FetchResponse> {
assert(this.#signal == null, "request already sent", "UNSUPPORTED_OPERATION", { operation: "fetchRequest.send" });
this.#signal = new FetchCancelSignal(this);
return this.#send(0, getTime() + this.timeout, 0, this, new FetchResponse(0, "", { }, null, this));
}
/**
* Cancels the inflight response, causing a ``CANCELLED``
* error to be rejected from the [[send]].
*/
cancel(): void {
assert(this.#signal != null, "request has not been sent", "UNSUPPORTED_OPERATION", { operation: "fetchRequest.cancel" });
const signal = fetchSignals.get(this);
if (!signal) { throw new Error("missing signal; should not happen"); }
signal();
}
/**
* Returns a new [[FetchRequest]] that represents the redirection
* to %%location%%.
*/
redirect(location: string): FetchRequest {
// Redirection; for now we only support absolute locataions
const current = this.url.split(":")[0].toLowerCase();
const target = location.split(":")[0].toLowerCase();
// Don't allow redirecting:
// - non-GET requests
// - downgrading the security (e.g. https => http)
// - to non-HTTP (or non-HTTPS) protocols [this could be relaxed?]
assert(this.method === "GET" && (current !== "https" || target !== "http") && location.match(/^https?:/), `unsupported redirect`, "UNSUPPORTED_OPERATION", {
operation: `redirect(${ this.method } ${ JSON.stringify(this.url) } => ${ JSON.stringify(location) })`
});
// Create a copy of this request, with a new URL
const req = new FetchRequest(location);
req.method = "GET";
req.allowGzip = this.allowGzip;
req.timeout = this.timeout;
req.#headers = Object.assign({ }, this.#headers);
if (this.#body) { req.#body = new Uint8Array(this.#body); }
req.#bodyType = this.#bodyType;
// Do not forward credentials unless on the same domain; only absolute
//req.allowInsecure = false;
// paths are currently supported; may want a way to specify to forward?
//setStore(req.#props, "creds", getStore(this.#pros, "creds"));
return req;
}
/**
* Create a new copy of this request.
*/
clone(): FetchRequest {
const clone = new FetchRequest(this.url);
// Preserve "default method" (i.e. null)
clone.#method = this.#method;
// Preserve "default body" with type, copying the Uint8Array is present
if (this.#body) { clone.#body = this.#body; }
clone.#bodyType = this.#bodyType;
// Preserve "default headers"
clone.#headers = Object.assign({ }, this.#headers);
// Credentials is readonly, so we copy internally
clone.#creds = this.#creds;
if (this.allowGzip) { clone.allowGzip = true; }
clone.timeout = this.timeout;
if (this.allowInsecureAuthentication) { clone.allowInsecureAuthentication = true; }
clone.#preflight = this.#preflight;
clone.#process = this.#process;
clone.#retry = this.#retry;
return clone;
}
/**
* Locks all static configuration for gateways and FetchGetUrlFunc
* registration.
*/
static lockConfig(): void {
locked = true;
}
/**
* Get the current Gateway function for %%scheme%%.
*/
static getGateway(scheme: string): null | FetchGatewayFunc {
return Gateways[scheme.toLowerCase()] || null;
}
/**
* Use the %%func%% when fetching URIs using %%scheme%%.
*
* This method affects all requests globally.
*
* If [[lockConfig]] has been called, no change is made and this
* throws.
*/
static registerGateway(scheme: string, func: FetchGatewayFunc): void {
scheme = scheme.toLowerCase();
if (scheme === "http" || scheme === "https") {
throw new Error(`cannot intercept ${ scheme }; use registerGetUrl`);
}
if (locked) { throw new Error("gateways locked"); }
Gateways[scheme] = func;
}
/**
* Use %%getUrl%% when fetching URIs over HTTP and HTTPS requests.
*
* This method affects all requests globally.
*
* If [[lockConfig]] has been called, no change is made and this
* throws.
*/
static registerGetUrl(getUrl: FetchGetUrlFunc): void {
if (locked) { throw new Error("gateways locked"); }
getUrlFunc = getUrl;
}
/**
* Creates a function that can "fetch" data URIs.
*
* Note that this is automatically done internally to support
* data URIs, so it is not necessary to register it.
*
* This is not generally something that is needed, but may
* be useful in a wrapper to perfom custom data URI functionality.
*/
static createDataGateway(): FetchGatewayFunc {
return dataGatewayFunc;
}
/**
* Creates a function that will fetch IPFS (unvalidated) from
* a custom gateway baseUrl.
*
* The default IPFS gateway used internally is
* ``"https:/\/gateway.ipfs.io/ipfs/"``.
*/
static createIpfsGatewayFunc(baseUrl: string): FetchGatewayFunc {
return getIpfsGatewayFunc(baseUrl);
}
}
interface ThrottleError extends Error {
stall: number;
throttle: true;
};
/**
* The response for a FetchREquest.
*/
export class FetchResponse implements Iterable<[ key: string, value: string ]> {
#statusCode: number;
#statusMessage: string;
#headers: Record<string, string>;
#body: null | Readonly<Uint8Array>;
#request: null | FetchRequest;
#error: { error?: Error, message: string };
toString(): string {
return `<FetchResponse status=${ this.statusCode } body=${ this.#body ? hexlify(this.#body): "null" }>`;
}
/**
* The response status code.
*/
get statusCode(): number { return this.#statusCode; }
/**
* The response status message.
*/
get statusMessage(): string { return this.#statusMessage; }
/**
* The response headers. All keys are lower-case.
*/
get headers(): Record<string, string> { return Object.assign({ }, this.#headers); }
/**
* The response body, or ``null`` if there was no body.
*/
get body(): null | Readonly<Uint8Array> {
return (this.#body == null) ? null: new Uint8Array(this.#body);
}
/**
* The response body as a UTF-8 encoded string, or the empty
* string (i.e. ``""``) if there was no body.
*
* An error is thrown if the body is invalid UTF-8 data.
*/
get bodyText(): string {
try {
return (this.#body == null) ? "": toUtf8String(this.#body);
} catch (error) {
assert(false, "response body is not valid UTF-8 data", "UNSUPPORTED_OPERATION", {
operation: "bodyText", info: { response: this }
});
}
}
/**
* The response body, decoded as JSON.
*
* An error is thrown if the body is invalid JSON-encoded data
* or if there was no body.
*/
get bodyJson(): any {
try {
return JSON.parse(this.bodyText);
} catch (error) {
assert(false, "response body is not valid JSON", "UNSUPPORTED_OPERATION", {
operation: "bodyJson", info: { response: this }
});
}
}
[Symbol.iterator](): Iterator<[ key: string, value: string ]> {
const headers = this.headers;
const keys = Object.keys(headers);
let index = 0;
return {
next: () => {
if (index < keys.length) {
const key = keys[index++];
return {
value: [ key, headers[key] ], done: false
}
}
return { value: undefined, done: true };
}
};
}
constructor(statusCode: number, statusMessage: string, headers: Readonly<Record<string, string>>, body: null | Uint8Array, request?: FetchRequest) {
this.#statusCode = statusCode;
this.#statusMessage = statusMessage;
this.#headers = Object.keys(headers).reduce((accum, k) => {
accum[k.toLowerCase()] = String(headers[k]);
return accum;
}, <Record<string, string>>{ });
this.#body = ((body == null) ? null: new Uint8Array(body));
this.#request = (request || null);
this.#error = { message: "" };
}
/**
* Return a Response with matching headers and body, but with
* an error status code (i.e. 599) and %%message%% with an
* optional %%error%%.
*/
makeServerError(message?: string, error?: Error): FetchResponse {
let statusMessage: string;
if (!message) {
message = `${ this.statusCode } ${ this.statusMessage }`;
statusMessage = `CLIENT ESCALATED SERVER ERROR (${ message })`;
} else {
statusMessage = `CLIENT ESCALATED SERVER ERROR (${ this.statusCode } ${ this.statusMessage }; ${ message })`;
}
const response = new FetchResponse(599, statusMessage, this.headers,
this.body, this.#request || undefined);
response.#error = { message, error };
return response;
}
/**
* If called within a [request.processFunc](FetchRequest-processFunc)
* call, causes the request to retry as if throttled for %%stall%%
* milliseconds.
*/
throwThrottleError(message?: string, stall?: number): never {
if (stall == null) {
stall = -1;
} else {
assertArgument(Number.isInteger(stall) && stall >= 0, "invalid stall timeout", "stall", stall);
}
const error = new Error(message || "throttling requests");
defineProperties(<ThrottleError>error, { stall, throttle: true });
throw error;
}
/**
* Get the header value for %%key%%, ignoring case.
*/
getHeader(key: string): string {
return this.headers[key.toLowerCase()];
}
/**
* Returns true of the response has a body.
*/
hasBody(): this is (FetchResponse & { body: Uint8Array }) {
return (this.#body != null);
}
/**
* The request made for this response.
*/
get request(): null | FetchRequest { return this.#request; }
/**
* Returns true if this response was a success statusCode.
*/
ok(): boolean {
return (this.#error.message === "" && this.statusCode >= 200 && this.statusCode < 300);
}
/**
* Throws a ``SERVER_ERROR`` if this response is not ok.
*/
assertOk(): void {
if (this.ok()) { return; }
let { message, error } = this.#error;
if (message === "") {
message = `server response ${ this.statusCode } ${ this.statusMessage }`;
}
assert(false, message, "SERVER_ERROR", {
request: (this.request || "unknown request"), response: this, error
});
}
}
function getTime(): number { return (new Date()).getTime(); }
function unpercent(value: string): Uint8Array {
return toUtf8Bytes(value.replace(/%([0-9a-f][0-9a-f])/gi, (all, code) => {
return String.fromCharCode(parseInt(code, 16));
}));
}
function wait(delay: number): Promise<void> {
return new Promise((resolve) => setTimeout(resolve, delay));
}