957 lines
31 KiB
TypeScript
957 lines
31 KiB
TypeScript
/**
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* Fetching content from the web is environment-specific, so Ethers
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* provides an abstraction the each environment can implement to provide
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* this service.
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*
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* On [Node.js](link-node), the ``http`` and ``https`` libs are used to
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* create a request object, register event listeners and process data
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* and populate the [[FetchResponse]].
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*
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* In a browser, the [DOM fetch](link-js-fetch) is used, and the resulting
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* ``Promise`` is waited on to retreive the payload.
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*
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* The [[FetchRequest]] is responsible for handling many common situations,
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* such as redirects, server throttling, authentcation, etc.
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*
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* It also handles common gateways, such as IPFS and data URIs.
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*
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* @_section api/utils/fetching:Fetching Web Content [about-fetch]
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*/
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import { decodeBase64, encodeBase64 } from "./base64.js";
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import { hexlify } from "./data.js";
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import { assert, assertArgument } from "./errors.js";
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import { defineProperties } from "./properties.js";
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import { toUtf8Bytes, toUtf8String } from "./utf8.js"
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import { createGetUrl } from "./geturl.js";
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/**
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* An environments implementation of ``getUrl`` must return this type.
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*/
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export type GetUrlResponse = {
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statusCode: number,
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statusMessage: string,
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headers: Record<string, string>,
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body: null | Uint8Array
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};
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/**
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* This can be used to control how throttling is handled in
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* [[FetchRequest-setThrottleParams]].
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*/
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export type FetchThrottleParams = {
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maxAttempts?: number;
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slotInterval?: number;
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};
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/**
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* Called before any network request, allowing updated headers (e.g. Bearer tokens), etc.
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*/
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export type FetchPreflightFunc = (req: FetchRequest) => Promise<FetchRequest>;
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/**
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* Called on the response, allowing client-based throttling logic or post-processing.
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*/
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export type FetchProcessFunc = (req: FetchRequest, resp: FetchResponse) => Promise<FetchResponse>;
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/**
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* Called prior to each retry; return true to retry, false to abort.
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*/
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export type FetchRetryFunc = (req: FetchRequest, resp: FetchResponse, attempt: number) => Promise<boolean>;
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/**
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* Called on Gateway URLs.
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*/
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export type FetchGatewayFunc = (url: string, signal?: FetchCancelSignal) => Promise<FetchRequest | FetchResponse>;
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/**
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* Used to perform a fetch; use this to override the underlying network
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* fetch layer. In NodeJS, the default uses the "http" and "https" libraries
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* and in the browser ``fetch`` is used. If you wish to use Axios, this is
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* how you would register it.
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*/
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export type FetchGetUrlFunc = (req: FetchRequest, signal?: FetchCancelSignal) => Promise<GetUrlResponse>;
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const MAX_ATTEMPTS = 12;
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const SLOT_INTERVAL = 250;
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// The global FetchGetUrlFunc implementation.
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let defaultGetUrlFunc: FetchGetUrlFunc = createGetUrl();
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const reData = new RegExp("^data:([^;:]*)?(;base64)?,(.*)$", "i");
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const reIpfs = new RegExp("^ipfs:/\/(ipfs/)?(.*)$", "i");
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// If locked, new Gateways cannot be added
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let locked = false;
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// https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URLs
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async function dataGatewayFunc(url: string, signal?: FetchCancelSignal): Promise<FetchResponse> {
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try {
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const match = url.match(reData);
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if (!match) { throw new Error("invalid data"); }
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return new FetchResponse(200, "OK", {
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"content-type": (match[1] || "text/plain"),
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}, (match[2] ? decodeBase64(match[3]): unpercent(match[3])));
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} catch (error) {
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return new FetchResponse(599, "BAD REQUEST (invalid data: URI)", { }, null, new FetchRequest(url));
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}
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}
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/**
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* Returns a [[FetchGatewayFunc]] for fetching content from a standard
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* IPFS gateway hosted at %%baseUrl%%.
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*/
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function getIpfsGatewayFunc(baseUrl: string): FetchGatewayFunc {
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async function gatewayIpfs(url: string, signal?: FetchCancelSignal): Promise<FetchRequest | FetchResponse> {
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try {
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const match = url.match(reIpfs);
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if (!match) { throw new Error("invalid link"); }
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return new FetchRequest(`${ baseUrl }${ match[2] }`);
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} catch (error) {
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return new FetchResponse(599, "BAD REQUEST (invalid IPFS URI)", { }, null, new FetchRequest(url));
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}
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}
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return gatewayIpfs;
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}
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const Gateways: Record<string, FetchGatewayFunc> = {
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"data": dataGatewayFunc,
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"ipfs": getIpfsGatewayFunc("https:/\/gateway.ipfs.io/ipfs/")
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};
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const fetchSignals: WeakMap<FetchRequest, () => void> = new WeakMap();
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/**
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* @_ignore
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*/
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export class FetchCancelSignal {
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#listeners: Array<() => void>;
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#cancelled: boolean;
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constructor(request: FetchRequest) {
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this.#listeners = [ ];
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this.#cancelled = false;
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fetchSignals.set(request, () => {
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if (this.#cancelled) { return; }
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this.#cancelled = true;
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for (const listener of this.#listeners) {
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setTimeout(() => { listener(); }, 0);
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}
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this.#listeners = [ ];
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});
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}
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addListener(listener: () => void): void {
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assert(!this.#cancelled, "singal already cancelled", "UNSUPPORTED_OPERATION", {
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operation: "fetchCancelSignal.addCancelListener"
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});
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this.#listeners.push(listener);
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}
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get cancelled(): boolean { return this.#cancelled; }
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checkSignal(): void {
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assert(!this.cancelled, "cancelled", "CANCELLED", { });
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}
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}
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// Check the signal, throwing if it is cancelled
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function checkSignal(signal?: FetchCancelSignal): FetchCancelSignal {
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if (signal == null) { throw new Error("missing signal; should not happen"); }
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signal.checkSignal();
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return signal;
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}
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/**
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* Represents a request for a resource using a URI.
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*
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* By default, the supported schemes are ``HTTP``, ``HTTPS``, ``data:``,
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* and ``IPFS:``.
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*
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* Additional schemes can be added globally using [[registerGateway]].
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*
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* @example:
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* req = new FetchRequest("https://www.ricmoo.com")
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* resp = await req.send()
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* resp.body.length
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* //_result:
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*/
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export class FetchRequest implements Iterable<[ key: string, value: string ]> {
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#allowInsecure: boolean;
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#gzip: boolean;
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#headers: Record<string, string>;
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#method: string;
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#timeout: number;
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#url: string;
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#body?: Uint8Array;
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#bodyType?: string;
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#creds?: string;
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// Hooks
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#preflight?: null | FetchPreflightFunc;
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#process?: null | FetchProcessFunc;
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#retry?: null | FetchRetryFunc;
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#signal?: FetchCancelSignal;
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#throttle: Required<FetchThrottleParams>;
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#getUrlFunc: null | FetchGetUrlFunc;
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/**
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* The fetch URI to requrest.
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*/
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get url(): string { return this.#url; }
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set url(url: string) {
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this.#url = String(url);
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}
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/**
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* The fetch body, if any, to send as the request body. //(default: null)//
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*
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* When setting a body, the intrinsic ``Content-Type`` is automatically
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* set and will be used if **not overridden** by setting a custom
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* header.
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*
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* If %%body%% is null, the body is cleared (along with the
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* intrinsic ``Content-Type``) and the .
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*
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* If %%body%% is a string, the intrincis ``Content-Type`` is set to
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* ``text/plain``.
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*
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* If %%body%% is a Uint8Array, the intrincis ``Content-Type`` is set to
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* ``application/octet-stream``.
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*
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* If %%body%% is any other object, the intrincis ``Content-Type`` is
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* set to ``application/json``.
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*/
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get body(): null | Uint8Array {
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if (this.#body == null) { return null; }
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return new Uint8Array(this.#body);
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}
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set body(body: null | string | Readonly<object> | Readonly<Uint8Array>) {
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if (body == null) {
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this.#body = undefined;
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this.#bodyType = undefined;
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} else if (typeof(body) === "string") {
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this.#body = toUtf8Bytes(body);
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this.#bodyType = "text/plain";
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} else if (body instanceof Uint8Array) {
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this.#body = body;
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this.#bodyType = "application/octet-stream";
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} else if (typeof(body) === "object") {
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this.#body = toUtf8Bytes(JSON.stringify(body));
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this.#bodyType = "application/json";
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} else {
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throw new Error("invalid body");
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}
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}
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/**
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* Returns true if the request has a body.
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*/
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hasBody(): this is (FetchRequest & { body: Uint8Array }) {
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return (this.#body != null);
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}
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/**
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* The HTTP method to use when requesting the URI. If no method
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* has been explicitly set, then ``GET`` is used if the body is
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* null and ``POST`` otherwise.
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*/
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get method(): string {
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if (this.#method) { return this.#method; }
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if (this.hasBody()) { return "POST"; }
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return "GET";
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}
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set method(method: null | string) {
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if (method == null) { method = ""; }
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this.#method = String(method).toUpperCase();
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}
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/**
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* The headers that will be used when requesting the URI. All
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* keys are lower-case.
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*
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* This object is a copy, so any chnages will **NOT** be reflected
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* in the ``FetchRequest``.
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*
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* To set a header entry, use the ``setHeader`` method.
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*/
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get headers(): Record<string, string> {
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const headers = Object.assign({ }, this.#headers);
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if (this.#creds) {
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headers["authorization"] = `Basic ${ encodeBase64(toUtf8Bytes(this.#creds)) }`;
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};
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if (this.allowGzip) {
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headers["accept-encoding"] = "gzip";
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}
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if (headers["content-type"] == null && this.#bodyType) {
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headers["content-type"] = this.#bodyType;
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}
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if (this.body) { headers["content-length"] = String(this.body.length); }
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return headers;
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}
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/**
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* Get the header for %%key%%, ignoring case.
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*/
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getHeader(key: string): string {
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return this.headers[key.toLowerCase()];
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}
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/**
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* Set the header for %%key%% to %%value%%. All values are coerced
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* to a string.
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*/
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setHeader(key: string, value: string | number): void {
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this.#headers[String(key).toLowerCase()] = String(value);
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}
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/**
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* Clear all headers, resetting all intrinsic headers.
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*/
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clearHeaders(): void {
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this.#headers = { };
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}
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[Symbol.iterator](): Iterator<[ key: string, value: string ]> {
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const headers = this.headers;
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const keys = Object.keys(headers);
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let index = 0;
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return {
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next: () => {
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if (index < keys.length) {
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const key = keys[index++];
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return {
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value: [ key, headers[key] ], done: false
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}
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}
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return { value: undefined, done: true };
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}
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};
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}
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/**
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* The value that will be sent for the ``Authorization`` header.
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*
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* To set the credentials, use the ``setCredentials`` method.
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*/
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get credentials(): null | string {
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return this.#creds || null;
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}
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/**
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* Sets an ``Authorization`` for %%username%% with %%password%%.
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*/
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setCredentials(username: string, password: string): void {
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assertArgument(!username.match(/:/), "invalid basic authentication username", "username", "[REDACTED]");
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this.#creds = `${ username }:${ password }`;
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}
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/**
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* Enable and request gzip-encoded responses. The response will
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* automatically be decompressed. //(default: true)//
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*/
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get allowGzip(): boolean {
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return this.#gzip;
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}
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set allowGzip(value: boolean) {
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this.#gzip = !!value;
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}
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/**
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* Allow ``Authentication`` credentials to be sent over insecure
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* channels. //(default: false)//
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*/
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get allowInsecureAuthentication(): boolean {
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return !!this.#allowInsecure;
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}
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set allowInsecureAuthentication(value: boolean) {
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this.#allowInsecure = !!value;
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}
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/**
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* The timeout (in milliseconds) to wait for a complere response.
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* //(default: 5 minutes)//
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*/
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get timeout(): number { return this.#timeout; }
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set timeout(timeout: number) {
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assertArgument(timeout >= 0, "timeout must be non-zero", "timeout", timeout);
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this.#timeout = timeout;
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}
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/**
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* This function is called prior to each request, for example
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* during a redirection or retry in case of server throttling.
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*
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* This offers an opportunity to populate headers or update
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* content before sending a request.
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*/
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get preflightFunc(): null | FetchPreflightFunc {
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return this.#preflight || null;
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}
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set preflightFunc(preflight: null | FetchPreflightFunc) {
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this.#preflight = preflight;
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}
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/**
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* This function is called after each response, offering an
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* opportunity to provide client-level throttling or updating
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* response data.
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*
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* Any error thrown in this causes the ``send()`` to throw.
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*
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* To schedule a retry attempt (assuming the maximum retry limit
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* has not been reached), use [[response.throwThrottleError]].
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*/
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get processFunc(): null | FetchProcessFunc {
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return this.#process || null;
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}
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set processFunc(process: null | FetchProcessFunc) {
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this.#process = process;
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}
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/**
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* This function is called on each retry attempt.
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*/
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get retryFunc(): null | FetchRetryFunc {
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return this.#retry || null;
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}
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set retryFunc(retry: null | FetchRetryFunc) {
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this.#retry = retry;
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}
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/**
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* This function is called to fetch content from HTTP and
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* HTTPS URLs and is platform specific (e.g. nodejs vs
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* browsers).
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*
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* This is by default the currently registered global getUrl
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* function, which can be changed using [[registerGetUrl]].
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* If this has been set, setting is to ``null`` will cause
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* this FetchRequest (and any future clones) to revert back to
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* using the currently registered global getUrl function.
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*
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* Setting this is generally not necessary, but may be useful
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* for developers that wish to intercept requests or to
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* configurege a proxy or other agent.
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*/
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get getUrlFunc(): FetchGetUrlFunc {
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return this.#getUrlFunc || defaultGetUrlFunc;
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}
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set getUrlFunc(value: null | FetchGetUrlFunc) {
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this.#getUrlFunc = value;
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}
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/**
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* Create a new FetchRequest instance with default values.
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*
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* Once created, each property may be set before issuing a
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* ``.send()`` to make the request.
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*/
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constructor(url: string) {
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this.#url = String(url);
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this.#allowInsecure = false;
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this.#gzip = true;
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this.#headers = { };
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this.#method = "";
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this.#timeout = 300000;
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this.#throttle = {
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slotInterval: SLOT_INTERVAL,
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maxAttempts: MAX_ATTEMPTS
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};
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this.#getUrlFunc = null;
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}
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toString(): string {
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return `<FetchRequest method=${ JSON.stringify(this.method) } url=${ JSON.stringify(this.url) } headers=${ JSON.stringify(this.headers) } body=${ this.#body ? hexlify(this.#body): "null" }>`;
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}
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/**
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* Update the throttle parameters used to determine maximum
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* attempts and exponential-backoff properties.
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*/
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setThrottleParams(params: FetchThrottleParams): void {
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if (params.slotInterval != null) {
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this.#throttle.slotInterval = params.slotInterval;
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}
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if (params.maxAttempts != null) {
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this.#throttle.maxAttempts = params.maxAttempts;
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}
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}
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async #send(attempt: number, expires: number, delay: number, _request: FetchRequest, _response: FetchResponse): Promise<FetchResponse> {
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if (attempt >= this.#throttle.maxAttempts) {
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return _response.makeServerError("exceeded maximum retry limit");
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}
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assert(getTime() <= expires, "timeout", "TIMEOUT", {
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operation: "request.send", reason: "timeout", request: _request
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});
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if (delay > 0) { await wait(delay); }
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let req = this.clone();
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const scheme = (req.url.split(":")[0] || "").toLowerCase();
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// Process any Gateways
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if (scheme in Gateways) {
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const result = await Gateways[scheme](req.url, checkSignal(_request.#signal));
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if (result instanceof FetchResponse) {
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let response = result;
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if (this.processFunc) {
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checkSignal(_request.#signal);
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try {
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response = await this.processFunc(req, response);
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} catch (error: any) {
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// Something went wrong during processing; throw a 5xx server error
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if (error.throttle == null || typeof(error.stall) !== "number") {
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response.makeServerError("error in post-processing function", error).assertOk();
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}
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// Ignore throttling
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}
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}
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return response;
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}
|
|
req = result;
|
|
}
|
|
|
|
// We have a preflight function; update the request
|
|
if (this.preflightFunc) { req = await this.preflightFunc(req); }
|
|
|
|
const resp = await this.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;
|
|
|
|
clone.#getUrlFunc = this.#getUrlFunc;
|
|
|
|
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"); }
|
|
defaultGetUrlFunc = getUrl;
|
|
}
|
|
|
|
/**
|
|
* Creates a getUrl function that fetches content from HTTP and
|
|
* HTTPS URLs.
|
|
*
|
|
* The available %%options%% are dependent on the platform
|
|
* implementation of the default getUrl function.
|
|
*
|
|
* This is not generally something that is needed, but is useful
|
|
* when trying to customize simple behaviour when fetching HTTP
|
|
* content.
|
|
*/
|
|
static createGetUrlFunc(options?: Record<string, any>): FetchGetUrlFunc {
|
|
return createGetUrl(options);
|
|
}
|
|
|
|
/**
|
|
* 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));
|
|
}
|