recaptcha-v3-v2/server-sample..js

Super small Recaptcha library. Uses Recaptcha v3 by default. Fails over to v2 when v3 score seems low. Detects darkmode automatically. Super simple setup. Requires server side setup. Cleans up after itself.

import * as functions from "firebase-functions";
import * as admin from "firebase-admin";
const axios = require("axios");
import * as cors from "cors";
const corsHandler = cors({ origin: true });

admin.initializeApp({
  credential: admin.credential.cert(
    Object.assign(
      {
        private_key: "your-server-private_key",
      },
      functions.config().serviceaccount
    )
  ),
  databaseURL: "your-firebase-db-url",
});

exports.sendRecaptcha = functions.https.onRequest(async (request, response) => {
  corsHandler(request, response, async () => {
    const USER_ERROR_CODES = [
      "missing-input-response",
      "invalid-input-response",
    ];
    let secret = functions.config().recaptcha.key; //your secret v3 recaptcha key

    const token = request.query.token;
    const version = request.query.version;

    if (Number(version) === 2) secret = functions.config().recaptcha.keyv2; // your secret v2 key

    try {
      const user_ip =
        request.headers["x-forwarded-for"] || request.connection.remoteAddress;
      functions.logger.log(user_ip);
      const result = await axios.post(
        `https://recaptcha.google.com/recaptcha/api/siteverify?secret=${secret}&response=${token}&remoteip=${user_ip}`,
        {
          secret: secret,
          response: token,
          remoteip: user_ip,
        },
        {
          headers: {
            "Content-Type": "application/x-www-form-urlencoded",
          },
        }
      );

      const data = result.data;

      if (data.success) {
        response.status(200).send(data);
      } else {
        const errorCodes = data["error-codes"];
        if (
          errorCodes.length == 1 &&
          USER_ERROR_CODES.includes(errorCodes[0])
        ) {
          response
            .status(400)
            .send({ error: errorCodes, errorText: "Invalid Input" });
        } else {
          response
            .status(500)
            .send({ error: errorCodes, errorText: "Internal Error" });
        }
      }
    } catch (error) {
      response.status(500).send({ error: error, errorText: "Internal Error" });
    }
  });
});