Function buildAuthRequest

apps/sim/lib/oauth/oauth.ts:1430–1465

* Build the authentication request headers and body for OAuth token refresh

(
  config: ProviderAuthConfig,
  refreshToken: string
)

 * Build the authentication request headers and body for OAuth token refresh
 */
function buildAuthRequest(
  config: ProviderAuthConfig,
  refreshToken: string
): { headers: Record<string, string>; bodyParams: Record<string, string>; useJsonBody?: boolean } {
  const headers: Record<string, string> = {
    'Content-Type': config.useJsonBody ? 'application/json' : 'application/x-www-form-urlencoded',
    ...config.additionalHeaders,
  }

  const bodyParams: Record<string, string> = {
    grant_type: 'refresh_token',
  }

  // Handle refresh token placement
  if (config.refreshTokenInAuthHeader) {
    // Cal.com style: refresh token in Authorization header as Bearer token
    headers.Authorization = `Bearer ${refreshToken}`
  } else {
    // Standard OAuth: refresh token in request body
    bodyParams.refresh_token = refreshToken
  }

  if (config.useBasicAuth) {
    // Use Basic Authentication - credentials in Authorization header only
    const basicAuth = Buffer.from(`${config.clientId}:${config.clientSecret}`).toString('base64')
    headers.Authorization = `Basic ${basicAuth}`
  } else {
    // Use body credentials - include client credentials in request body
    bodyParams.client_id = config.clientId
    if (config.clientSecret) {
      bodyParams.client_secret = config.clientSecret
    }
  }

  return { headers, bodyParams, useJsonBody: config.useJsonBody }
}

function getBaseProviderForService(providerId: string): string {
  if (providerId in OAUTH_PROVIDERS) {