story-research-zapwall/pages/api/nip95-upload/proxyRequest.ts

import type { UploadedFile, ProxyUploadResponse } from './types'
import FormData from 'form-data'
import fs from 'fs'
import https from 'https'
import http from 'http'
import { URL } from 'url'
import { getFormDataHeaders, getRedirectLocation } from './utils'
import { handleProxyRequestError } from './proxyRequestErrors'

export async function makeRequestWithRedirects(params: {
  targetEndpoint: string
  url: URL
  file: UploadedFile
  authToken: string | undefined
  redirectCount: number
  maxRedirects: number
}): Promise<ProxyUploadResponse> {
  if (params.redirectCount > params.maxRedirects) {
    throw new Error(`Too many redirects (max ${params.maxRedirects})`)
  }
  const response = await makeRequestOnce({ targetEndpoint: params.targetEndpoint, url: params.url, file: params.file, authToken: params.authToken })
  const redirectUrl = tryGetRedirectUrl({ url: params.url, response })
  if (!redirectUrl) {
    return response
  }
  console.warn('NIP-95 proxy redirect:', { from: params.url.toString(), to: redirectUrl.toString(), statusCode: response.statusCode, redirectCount: params.redirectCount + 1 })
  return makeRequestWithRedirects({ ...params, url: redirectUrl, redirectCount: params.redirectCount + 1 })
}

async function makeRequestOnce(params: { targetEndpoint: string; url: URL; file: UploadedFile; authToken: string | undefined }): Promise<ProxyUploadResponse> {
  const { requestFormData, fileStream } = buildUploadFormData(params.file)
  const headers = buildProxyRequestHeaders(requestFormData, params.authToken)
  const { clientModule, requestOptions } = buildProxyRequestOptions({ url: params.url, headers })
  return sendFormDataRequest({ clientModule, requestOptions, requestFormData, fileStream, targetEndpoint: params.targetEndpoint, hostname: params.url.hostname, finalUrl: params.url.toString(), filepath: params.file.filepath })
}

function tryGetRedirectUrl(params: { url: URL; response: ProxyUploadResponse }): URL | null {
  if (!isRedirectStatus(params.response.statusCode)) {
    return null
  }
  const location = getRedirectLocation(params.response.headers as unknown)
  if (!location) {
    throw new Error('Redirect response missing location header')
  }
  try {
    return new URL(location, params.url.toString())
  } catch (urlError) {
    console.error('NIP-95 proxy invalid redirect URL:', { location, error: urlError instanceof Error ? urlError.message : 'Unknown error' })
    throw new Error(`Invalid redirect URL: ${location}`)
  }
}

function isRedirectStatus(statusCode: number): boolean {
  return statusCode === 301 || statusCode === 302 || statusCode === 307 || statusCode === 308
}

function buildUploadFormData(file: UploadedFile): { requestFormData: FormData; fileStream: fs.ReadStream } {
  const requestFormData = new FormData()
  const fileStream = fs.createReadStream(file.filepath)
  requestFormData.append('file', fileStream, { filename: file.originalFilename ?? file.newFilename ?? 'upload', contentType: file.mimetype ?? 'application/octet-stream' })
  return { requestFormData, fileStream }
}

function buildProxyRequestHeaders(requestFormData: FormData, authToken: string | undefined): http.OutgoingHttpHeaders {
  const headers = getFormDataHeaders(requestFormData)
  headers.Accept = 'application/json'
  headers['User-Agent'] = 'zapwall.fr/1.0'
  if (authToken) {
    headers.Authorization = `Nostr ${authToken}`
  }
  return headers
}

function buildProxyRequestOptions(params: { url: URL; headers: http.OutgoingHttpHeaders }): { clientModule: typeof http | typeof https; requestOptions: http.RequestOptions } {
  const isHttps = params.url.protocol === 'https:'
  return {
    clientModule: isHttps ? https : http,
    requestOptions: { hostname: params.url.hostname, port: params.url.port ?? (isHttps ? 443 : 80), path: params.url.pathname + params.url.search, method: 'POST', headers: params.headers, timeout: 30000 },
  }
}

async function sendFormDataRequest(params: {
  clientModule: typeof http | typeof https
  requestOptions: http.RequestOptions
  requestFormData: FormData
  fileStream: fs.ReadStream
  targetEndpoint: string
  hostname: string
  finalUrl: string
  filepath: string
}): Promise<ProxyUploadResponse> {
  return new Promise<ProxyUploadResponse>((resolve, reject) => {
    const proxyRequest = params.clientModule.request(params.requestOptions, (proxyResponse: http.IncomingMessage) => {
      void readProxyResponse({ proxyResponse, finalUrl: params.finalUrl }).then(resolve).catch(reject)
    })
    attachProxyRequestHandlers({ proxyRequest, requestFormData: params.requestFormData, fileStream: params.fileStream, targetEndpoint: params.targetEndpoint, hostname: params.hostname, filepath: params.filepath, reject })
    params.requestFormData.pipe(proxyRequest)
  })
}

function attachProxyRequestHandlers(params: {
  proxyRequest: http.ClientRequest
  requestFormData: FormData
  fileStream: fs.ReadStream
  targetEndpoint: string
  hostname: string
  filepath: string
  reject: (error: unknown) => void
}): void {
  params.proxyRequest.setTimeout(30000, () => {
    params.proxyRequest.destroy()
    params.reject(new Error('Request timeout after 30 seconds'))
  })
  params.proxyRequest.on('error', (error) => {
    params.reject(handleProxyRequestError({ error, targetEndpoint: params.targetEndpoint, hostname: params.hostname }))
  })
  params.requestFormData.on('error', (error) => {
    console.error('NIP-95 proxy FormData error:', { targetEndpoint: params.targetEndpoint, hostname: params.hostname, error })
    params.reject(error)
  })
  params.fileStream.on('error', (error) => {
    console.error('NIP-95 proxy file stream error:', { targetEndpoint: params.targetEndpoint, hostname: params.hostname, filepath: params.filepath, error })
    params.reject(error)
  })
}

async function readProxyResponse(params: { proxyResponse: http.IncomingMessage; finalUrl: string }): Promise<ProxyUploadResponse> {
  const statusCode = params.proxyResponse.statusCode ?? 500
  const body = await readIncomingMessageBody(params.proxyResponse)
  return { statusCode, statusMessage: params.proxyResponse.statusMessage ?? 'Internal Server Error', body, headers: params.proxyResponse.headers, finalUrl: params.finalUrl }
}

async function readIncomingMessageBody(message: http.IncomingMessage): Promise<string> {
  return new Promise<string>((resolve, reject) => {
    let body = ''
    message.setEncoding('utf8')
    message.on('data', (chunk) => {
      body += chunk
    })
    message.on('end', () => resolve(body))
    message.on('error', reject)
  })
}