Delphi Twebbrowser Validate Recaptcha

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I am accessing a site to search for some information, I am using Delphi with the twebbrower component, but has a validation with recaptcha, someone knows me how to validate the recaptcha via programming?

delphi recaptcha

  • What have you tried?

  • I’ve been a programmer for a long time, but in this case I don’t know where to start

2 answers

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reCAPTCHA/CAPTCHA function is exactly this. Prevent validation/access from being done via programming.

CAPTCHA is one of the measures to protect restricted areas, forms and other things from bots/robots that attempt to access, validate or send information.

Imagine a user registration or some search with basic fields (Start and End Date, CPF, etc), 99% of these cases are resources that can be accessed by anyone who makes a GET request.

Without the protection of a CAPTCHA, it would be "easy" for any "hacker" to build a bot that keeps making GET requests, filling in the data and submitting the information.

Depending on how many bots have been programmed, there can be a huge bottleneck of requests being made and information being recorded in the database. Causing a severe overhead on servers and data recorded in the database.

The best way is to check if the service that is doing the search, provides some kind of API or Webservice for developers to query.

If there is no type of API/Webservice, why not show and ask the user to fill only CAPTCHA or even the entire site within your system?

Other than that, it is trying to "circumvent" validation by parsing/analyzing HTML and possible CAPTCHA (Image Processing) images, or trying to find some component/lib from someone who has already done so. Which is something I don’t recommend at all, because in addition to breaking a service safety rule, work and complexity will be great.

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Currently there are services that provide the captcha solution, usually charge for each solution.

If you inspect the page you will see that just below the reCaptcha there is a tag called <textarea id="g-recaptcha-response" ...>. It is possible to return this solution provided by the API that solves Captcha, IE, just send the captcha data to the API, receive the solution and add in this field, then just forward on the page.

An example of a service is the Anti-captcha. On the website of this service you can find examples of how to get the captcha and make the requisitions.

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