hermes-agent/apps/desktop/electron/oauth-session-response.ts

import { Buffer } from 'node:buffer'

import { httpStatusError } from './api-transport'

// Response-stream extraction based on Bartok9's #99135 (original issue #72530).
export interface OauthResponseLike {
  on(event: 'data', cb: (chunk: Buffer) => void): void
  on(event: 'error', cb: (error: Error) => void): void
  on(event: 'end', cb: () => void): void
  statusCode?: number
  headers: Record<string, string | string[] | undefined>
}

export interface WireOauthResponseOptions {
  url: string
  isTimedOut: () => boolean
  clearTimer: () => void
  resolve: (value: unknown) => void
  reject: (error: Error) => void
}

export function wireOauthSessionResponse(res: OauthResponseLike, opts: WireOauthResponseOptions): void {
  const { url, isTimedOut, clearTimer, resolve, reject } = opts
  const chunks: Buffer[] = []
  let settled = false

  res.on('data', chunk => {
    if (!settled && !isTimedOut()) {
      chunks.push(Buffer.from(chunk))
    }
  })
  // Electron emits post-header loader failures on the response, not the request.
  // Keep the listener after settlement: a late error must not become uncaught.
  res.on('error', error => {
    if (settled || isTimedOut()) {
      return
    }

    settled = true
    chunks.length = 0
    clearTimer()
    reject(error)
  })
  res.on('end', () => {
    if (settled || isTimedOut()) {
      return
    }

    settled = true
    clearTimer()
    const text = Buffer.concat(chunks).toString('utf8')
    chunks.length = 0
    const statusCode = res.statusCode || 500

    if (statusCode >= 400) {
      reject(httpStatusError(statusCode, text))

      return
    }

    if (!text) {
      resolve(null)

      return
    }

    const looksHtml = /^\s*<(?:!doctype|html)/i.test(text)
    const contentType = String(res.headers['content-type'] || res.headers['Content-Type'] || '')

    if (looksHtml || contentType.includes('text/html')) {
      reject(new Error(`Expected JSON from ${url} but got HTML (status ${statusCode}).`))

      return
    }

    try {
      resolve(JSON.parse(text))
    } catch {
      reject(new Error(`Invalid JSON from ${url} (status ${statusCode}): ${text.slice(0, 200)}`))
    }
  })
}