fraud-check/app.js

const axios = require("axios");

const getIpInfo = async (ip, custom) => {
  let link =
    custom && custom.link && custom.key
      ? custom.link
      : "http://ip-api.com/json/";
  return (
    await axios.get(link.replace(/\/?$/, "/") + ip, {
      params: {
        fields: "status,countryCode,proxy,hosting",
        key: custom ? custom.key : custom,
      },
    })
  ).data;
};

const validateIp = (ip) => {
  // IPv4 validation
  const ipv4Pattern = /^((25[0-5]|(2[0-4]|1[0-9]|[1-9]|)[0-9])(\.(?!$)|$)){4}$/;
  if (ipv4Pattern.test(ip)) {
    return ip.split(".").every((octet) => parseInt(octet, 10) <= 255);
  }

  // IPv6 validation
  const ipv6Pattern =
    /^([0-9a-f]{1,4}:){7}([0-9a-f]{1,4})$|^(([0-9a-f]{1,4}:){0,6})?::((([0-9a-f]{1,4}:){0,6})([0-9a-f]{1,4}))?$/i;
  return ipv6Pattern.test(ip);
};

exports.verify = async ({ ip, countryArr, custom }) => {
  if (validateIp(ip)) {
    const { status, countryCode, proxy, hosting } = await getIpInfo(ip, custom);
    if (status === "fail") return true;
    return !(
      proxy ||
      hosting ||
      (Array.isArray(countryArr) ? countryArr.includes(countryCode) : false)
    );
  }
  return false;
};

exports.accept = async ({ ip, countryArr, custom }) => {
  if (validateIp(ip)) {
    const { status, countryCode, proxy, hosting } = await getIpInfo(ip, custom);
    if (status === "fail") return true;
    return !(
      proxy ||
      hosting ||
      (Array.isArray(countryArr) ? !countryArr.includes(countryCode) : false)
    );
  }
  return false;
};

exports.verifyWithReason = async ({ ip, countryArr, custom }) => {
  if (validateIp(ip)) {
    const { status, countryCode, proxy, hosting } = await getIpInfo(ip, custom);
    if (status === "fail")
      return {
        valid: true,
        proxy,
        hosting,
      };
    return {
      valid: !(
        proxy ||
        hosting ||
        (Array.isArray(countryArr) ? countryArr.includes(countryCode) : false)
      ),
      proxy,
      hosting,
      country: Array.isArray(countryArr)
        ? countryArr.includes(countryCode)
        : false,
    };
  }
  return {
    valid: false,
    proxy: false,
    hosting: false,
  };
};

exports.acceptWithReason = async ({ ip, countryArr, custom }) => {
  if (validateIp(ip)) {
    const { status, countryCode, proxy, hosting } = await getIpInfo(ip, custom);
    if (status === "fail")
      return {
        valid: true,
        proxy,
        hosting,
      };
    return {
      valid: !(
        proxy ||
        hosting ||
        (Array.isArray(countryArr) ? !countryArr.includes(countryCode) : false)
      ),
      proxy,
      hosting,
      country: Array.isArray(countryArr)
        ? !countryArr.includes(countryCode)
        : false,
    };
  }
  return {
    valid: false,
    proxy: false,
    hosting: false,
  };
};