yaak/plugins/auth-oauth2/src/fetchAccessToken.ts

import type { Context, HttpRequest, HttpUrlParameter } from '@yaakapp/api';
import { readFileSync } from 'node:fs';
import type { AccessTokenRawResponse } from './store';

export async function fetchAccessToken(
  ctx: Context,
  {
    accessTokenUrl,
    scope,
    audience,
    params,
    grantType,
    credentialsInBody,
    clientId,
    clientSecret,
  }: {
    clientId: string;
    clientSecret: string;
    grantType: string;
    accessTokenUrl: string;
    scope: string | null;
    audience: string | null;
    credentialsInBody: boolean;
    params: HttpUrlParameter[];
  },
): Promise<AccessTokenRawResponse> {
  console.log('[oauth2] Getting access token', accessTokenUrl);
  const httpRequest: Partial<HttpRequest> = {
    method: 'POST',
    url: accessTokenUrl,
    bodyType: 'application/x-www-form-urlencoded',
    body: {
      form: [{ name: 'grant_type', value: grantType }, ...params],
    },
    headers: [
      { name: 'User-Agent', value: 'yaak' },
      { name: 'Accept', value: 'application/x-www-form-urlencoded, application/json' },
      { name: 'Content-Type', value: 'application/x-www-form-urlencoded' },
    ],
  };

  if (scope) httpRequest.body!.form.push({ name: 'scope', value: scope });
  if (audience) httpRequest.body!.form.push({ name: 'audience', value: audience });

  if (credentialsInBody) {
    httpRequest.body!.form.push({ name: 'client_id', value: clientId });
    httpRequest.body!.form.push({ name: 'client_secret', value: clientSecret });
  } else {
    const value = 'Basic ' + Buffer.from(`${clientId}:${clientSecret}`).toString('base64');
    httpRequest.headers!.push({ name: 'Authorization', value });
  }

  httpRequest.authenticationType = 'none'; // Don't inherit workspace auth
  const resp = await ctx.httpRequest.send({ httpRequest });

  console.log('[oauth2] Got access token response', resp.status);

  const body = resp.bodyPath ? readFileSync(resp.bodyPath, 'utf8') : '';

  if (resp.status < 200 || resp.status >= 300) {
    throw new Error(
      'Failed to fetch access token with status=' + resp.status + ' and body=' + body,
    );
  }

  let response;
  try {
    response = JSON.parse(body);
  } catch {
    response = Object.fromEntries(new URLSearchParams(body));
  }

  if (response.error) {
    throw new Error('Failed to fetch access token with ' + response.error);
  }

  return response;
}