Get autonomous system information by IP address

type Cloudflare = {

  token: string;

  email: string;

  key: string;

};

/**

 * Get autonomous system information by IP address

 * Get the requested autonomous system information based on IP address. Population estimates come from APNIC (refer to https://labs.apnic.net/?p=526).

 */

export async function main(

  auth: Cloudflare,

  ip: string | undefined,

  format: "JSON" | "CSV" | undefined

) {

  const url = new URL(

    `https://api.cloudflare.com/client/v4/radar/entities/asns/ip`

  );

  for (const [k, v] of [

    ["ip", ip],

    ["format", format],

  ]) {

    if (v !== undefined && v !== "") {

      url.searchParams.append(k, v);

    }

  }

  const response = await fetch(url, {

    method: "GET",

    headers: {

      "X-AUTH-EMAIL": auth.email,

      "X-AUTH-KEY": auth.key,

      Authorization: "Bearer " + auth.token,

    },

    body: undefined,

  });

  if (!response.ok) {

    const text = await response.text();

    throw new Error(`${response.status} ${text}`);

  }

  return await response.json();

}