feat(core): Replace client-oauth2 with an in-repo package (#6266)

Co-authored-by: Marcus <marcus@n8n.io>

packages/@n8n/client-oauth2/src/ClientOAuth2.ts

@@ -0,0 +1,112 @@
+/* eslint-disable @typescript-eslint/no-unsafe-return */
+/* eslint-disable @typescript-eslint/no-unsafe-argument */
+/* eslint-disable @typescript-eslint/no-unsafe-assignment */
+/* eslint-disable @typescript-eslint/restrict-plus-operands */
+/* eslint-disable @typescript-eslint/no-explicit-any */
+import * as qs from 'querystring';
+import axios from 'axios';
+import { getAuthError } from './utils';
+import type { ClientOAuth2TokenData } from './ClientOAuth2Token';
+import { ClientOAuth2Token } from './ClientOAuth2Token';
+import { CodeFlow } from './CodeFlow';
+import { CredentialsFlow } from './CredentialsFlow';
+import type { Headers, Query } from './types';
+
+export interface ClientOAuth2RequestObject {
+	url: string;
+	method: 'DELETE' | 'GET' | 'HEAD' | 'PATCH' | 'POST' | 'PUT';
+	body?: Record<string, any>;
+	query?: Query;
+	headers?: Headers;
+}
+
+export interface ClientOAuth2Options {
+	clientId: string;
+	clientSecret: string;
+	accessTokenUri: string;
+	authorizationUri?: string;
+	redirectUri?: string;
+	scopes?: string[];
+	authorizationGrants?: string[];
+	state?: string;
+	body?: Record<string, any>;
+	query?: Query;
+	headers?: Headers;
+}
+
+class ResponseError extends Error {
+	constructor(readonly status: number, readonly body: object, readonly code = 'ESTATUS') {
+		super(`HTTP status ${status}`);
+	}
+}
+
+/**
+ * Construct an object that can handle the multiple OAuth 2.0 flows.
+ */
+export class ClientOAuth2 {
+	code: CodeFlow;
+
+	credentials: CredentialsFlow;
+
+	constructor(readonly options: ClientOAuth2Options) {
+		this.code = new CodeFlow(this);
+		this.credentials = new CredentialsFlow(this);
+	}
+
+	/**
+	 * Create a new token from existing data.
+	 */
+	createToken(data: ClientOAuth2TokenData, type?: string): ClientOAuth2Token {
+		return new ClientOAuth2Token(this, {
+			...data,
+			...(typeof type === 'string' ? { token_type: type } : type),
+		});
+	}
+
+	/**
+	 * Attempt to parse response body as JSON, fall back to parsing as a query string.
+	 */
+	private parseResponseBody<T extends object>(body: string): T {
+		try {
+			return JSON.parse(body);
+		} catch (e) {
+			return qs.parse(body) as T;
+		}
+	}
+
+	/**
+	 * Using the built-in request method, we'll automatically attempt to parse
+	 * the response.
+	 */
+	async request<T extends object>(options: ClientOAuth2RequestObject): Promise<T> {
+		let url = options.url;
+		const query = qs.stringify(options.query);
+
+		if (query) {
+			url += (url.indexOf('?') === -1 ? '?' : '&') + query;
+		}
+
+		const response = await axios.request({
+			url,
+			method: options.method,
+			data: qs.stringify(options.body),
+			headers: options.headers,
+			transformResponse: (res) => res,
+			// Axios rejects the promise by default for all status codes 4xx.
+			// We override this to reject promises only on 5xxs
+			validateStatus: (status) => status < 500,
+		});
+
+		const body = this.parseResponseBody<T>(response.data);
+
+		// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+		// @ts-ignore
+		const authErr = getAuthError(body);
+		if (authErr) throw authErr;
+
+		if (response.status < 200 || response.status >= 399)
+			throw new ResponseError(response.status, response.data);
+
+		return body;
+	}
+}