Create simple POS with React, Node and MongoDB #5: Setup ReCaptcha and define CORS

06Mar

Krissanawat KaewsanmuangJavaScript, Node.js, POS Tutorial, React

Defenition: POS – “Point of Sale”. At the point of sale, the merchant calculates the amount owed by the customer, indicates that amount, may prepare an invoice for the customer (which may be a cash register printout), and indicates the options for the customer to make payment.

Setup ReCaptcha and define CORSPrevious article: Optimize App and Setup Deployment Workflow.

For the Frontend, we will use ReCaptcha protected form;

For backend, we will define CORS, which will be receiving requests only from the Frontend.

Setup ReCaptcha protected frontend

Step one: We will get Recaptcha key from Google

Step two: Add our whitelist domain, then choose localhost and Netlify, then grab Recaptcha key, and finally, set up on Netlify first

Step three: Setting up on Netlify. Go to Netlify dashboard and setup Recaptcha Key as an environment variable

Step four: Now come back to local and install React Captcha package

npm install react-recaptcha

Step five: Next step is to import Recaptcha

import Recaptcha from "react-recaptcha";

Step six: Add validation rule name Recaptcha as required

const LoginSchema = Yup.object().shape({
   username: Yup.string()
                .min(2, "username is Too Short!")
                .max(50, "username is Too Long!")
                .required("Username is Required"),
            recaptcha: Yup.string().required(),
            password: Yup.string().required("Password is required")
   });

Step seven: We will create a function for initializing Recaptcha

initilizeRecaptcha = async => {
    const script = document.createElement("script");
    script.src = "https://www.google.com/recaptcha/api.js";
    script.async = true;
    script.defer = true;
    document.body.appendChild(script);
  };
  componentDidMount() {
    this.initilizeRecaptcha();
}

Last step: Add <Recaptcha> component and a validation message

<div className="form-group">
          <label>Recaptcha Validation</label>
          <Recaptcha
            sitekey={process.env.REACT_APP_RECAPCHA_KEY}
            render="explicit"
            theme="light"
            verifyCallback={response => {
              setFieldValue("recaptcha", response);
            }}
            onloadCallback={() => {
              console.log("done loading!");
            }}
          />
     {errors.recaptcha && touched.recaptcha && <p>{errors.recaptcha}</p>}
 </div>

Your final result should look like the image below

One more step: We’ll be adding register and forgot password form

You will be able to fill all input, but can’t submit without resolving the Recaptcha

this image show result when we didn't verify ReCaptcha — ReCaptcha require validation

The last thing is to push to GitHub which will also auto-deploy to Netlify

Setup CORS protected backend

Now we want to add whitelist IP or domain name to CORS option, open index.js on backend side then update CORS as seen in the image below;

var allowedOrigins = ['http://localhost:3000',
                      'https://basicpos.netlify.com/'];
app.use(cors({
  origin: function(origin, callback){
    // allow requests with no origin 
    // (like mobile apps or curl requests)
    if(!origin) return callback(null, true);
    if(allowedOrigins.indexOf(origin) === -1){
      var msg = 'The CORS policy for this site does not ' +
                'allow access from the specified Origin.';
      return res.json({status:'error',msg});
    }
    return callback(null, true);
  }
}));

If an error occurs, try changing to another domain

display CORS error result — CORS error result

Now push the updated code to Github. Finally, we can now protect our backend from unknown request

Conclusion

In this chapter, we have learned how to make our apps safe on the internet by setting up Recaptcha on React and CORS on Express. next chapter we will add redux that make our app are solid foundation one last thing your will find code for this chapter on this backend branch and frontend branch