Files
undergroundwires 799fb091b8 Fix failing URL status checking integration tests
Implement following redirects over `fetch` supporting cookies.
`node-fetch` does not support sending cookies during redirect. However,
this is needed to not end-up in a redirect loop for a sign-in callback.

Fix integration tests failing due to redirects and 403 errors:
  - Many redirects from `answers.microsoft.com` was throwing: throwing
    `FetchError: maximum redirect reached` error. It was caused by not
    having cookies when following redirects therefore having an infinite
    sign-in callback for the webpage.
  - Fixes integration tests failing due to additional referer header being
    sent by the application. It adds support for making exceptions to
    additional header sending through a list of regexes.

Add in-depth documentation for URL status checking.
2021-10-30 16:19:10 +01:00

67 lines
2.2 KiB
TypeScript

import fetch from 'cross-fetch';
export function fetchFollow(
url: string, fetchOptions: RequestInit, followOptions: IFollowOptions): Promise<Response> {
followOptions = { ...DefaultOptions, ...followOptions };
if (!followOptions.followRedirects
|| followOptions.maximumRedirectFollowDepth === 0) {
return fetch(url, fetchOptions);
}
fetchOptions = { ...fetchOptions, redirect: 'manual' /* handled manually */ };
const cookies = new CookieStorage(followOptions.enableCookies);
return followRecursivelyWithCookies(
url, fetchOptions, followOptions.maximumRedirectFollowDepth, cookies);
}
export interface IFollowOptions {
followRedirects?: boolean;
maximumRedirectFollowDepth?: number;
enableCookies?: boolean;
}
const DefaultOptions: IFollowOptions = {
followRedirects: true,
maximumRedirectFollowDepth: 20,
enableCookies: true,
};
async function followRecursivelyWithCookies(
url: string, options: RequestInit, followDepth: number, cookies: CookieStorage): Promise<Response> {
if (cookies.hasAny()) {
options = { ...options, headers: { ...options.headers, cookie: cookies.getHeader() } };
}
const response = await fetch(url, options);
if (!isRedirect(response.status)) {
return response;
}
if (--followDepth < 0) {
throw new Error(`[max-redirect] maximum redirect reached at: ${url}`);
}
const cookieHeader = response.headers.get('set-cookie');
cookies.addHeader(cookieHeader);
const nextUrl = response.headers.get('location');
return followRecursivelyWithCookies(nextUrl, options, followDepth, cookies);
}
function isRedirect(code: number): boolean {
return code === 301 || code === 302 || code === 303 || code === 307 || code === 308;
}
class CookieStorage {
public cookies = new Array<string>();
constructor(private readonly enabled: boolean) {
}
public hasAny() {
return this.enabled && this.cookies.length > 0;
}
public addHeader(header: string) {
if (!this.enabled || !header) {
return;
}
this.cookies.push(header);
}
public getHeader() {
return this.cookies.join(' ; ');
}
}