Function proxyRequest

packages/dev-proxy/src/server.ts:174–208

(
  context: Context,
  route: DevProxyRoute,
  fetchImpl: typeof globalThis.fetch,
  allowedOrigins: DevProxyCorsAllowedOrigins,
)

}

const proxyRequest = async (
  context: Context,
  route: DevProxyRoute,
  fetchImpl: typeof globalThis.fetch,
  allowedOrigins: DevProxyCorsAllowedOrigins,
) => {
  const requestUrl = new URL(context.req.url)
  const targetUrl = buildUpstreamUrl(route.target, requestUrl.pathname, requestUrl.search)
  const requestHeaders = createProxyRequestHeaders(context.req.raw, targetUrl, route.cookieRewrite)
  const requestInit: RequestInit & { duplex?: 'half' } = {
    method: context.req.method,
    headers: requestHeaders,
    redirect: 'manual',
  }

  if (context.req.method !== 'GET' && context.req.method !== 'HEAD') {
    requestInit.body = context.req.raw.body
    requestInit.duplex = 'half'
  }

  const upstreamResponse = await fetchImpl(targetUrl, requestInit)
  const responseHeaders = createUpstreamResponseHeaders(
    upstreamResponse,
    targetUrl,
    context.req.header('origin'),
    allowedOrigins,
    route.cookieRewrite,
  )

  return new Response(upstreamResponse.body, {
    status: upstreamResponse.status,
    statusText: upstreamResponse.statusText,
    headers: responseHeaders,
  })
}

const normalizeRoutePaths = (paths: DevProxyRoute['paths']) => Array.isArray(paths) ? paths : [paths]