How to parse people who are in a VKontakte group?

Question

JavaScript

Hello, the question may not be common for this resource, but still.
I am writing a parser, I want to get data about people who are in VK groups. I don't know how to be. I used several methods:
1) I downloaded a DOM document and parsed its code, but everything goes through JavaScript, so this method did not allow parsing more than 20 - 30 people who are initially visible. Used WebClient way, DownloadString method.
2) Worked with SeleniumHQ library. (The program does everything) Specifically: I launch the browser, open the page with group members, start scrolling down so that JS shows me all the members of the group, reach the maximum depth and use CSSSelectors to take the data I need, but AGAIN NO. VK does not allow me to see more than 901 members of the group (I want both 100k and 1kk). I don’t know how to be, if there is a way to get information about group members (at least their ID), then please write.
Also, if you have resources in your memory where you can learn in detail about multithreading and asynchronous download / download, then please send me an answer.
In advance, thank you all for your help. Ps I didn’t understand the VK API, as I understand it is required to implement software for VK users.

Answer 1

Of course, you need to use the VKontakte API. Understand, it's easy. You will need the groups.getMembers() method .
I posted on github an example of downloading the list of Members of VKontakte groups. Demo . It uses a web worker for downloading, a limit of 3 requests per second is taken into account. Requests are grouped in batches of 25 in the execute() method to speed up the download of large group Members lists.

Answer 2

Api vk getmembers
Detailing via getuser