Multiple ajax calls via recursive function and DDOS-ing ourselves

问题

In the comment by the link Jquery multiple Ajax Request in array loop the author said that making ajax requests in a loop may end up DDOS-ing ourselves.

Does that apply only a loop or multiple ajax calls in general? I mean may the risk of DDOS-ing be as well if I make multiple ajax requests via recursive function like

ajax(0);

ajax(index) {
    var xhr = new XMLHttpRequest();
    xhr.onreadystatechange = function() {
        if(this.readyState == 4 && this.status == 200) {
            ajax(index+1)
        }
    };
    xhr.open('POST', 'http://example.com/ajax_handler.php');
    xhr.setRequestHeader('Content-type', 'application/x-www-form-urlencoded; charset=UTF-8');
    xhr.send();
}

ps. I understand that we can "congregate all data together then send that in a single request to the server", but I need to run generating static pages passing data from the client to the server. So if there are dozens of thousands of pages I must to pass to the server via AJAX, they can't be passing as one single request because of limit of POST requests.

Why so? I would just like to keep all the logic of the generator at the client and call at the server only standard operations like reading and writing files. That is the client reads templates and content via ajax and server reading function, build page html according to its logic and pass the whole html to the server to be written in a html file

回答1:

The problem Rory McCrossan was describing was if you make multiple requests at once. If you have lots of requests, you might overload the server (and/or your network connection) - you shouldn't make tons of requests at once. (Probably best to not send more than 5 request a second to a server, or something like that.)

But in your code, you're not sending out the requests at once; you only have at most one request active at any time, so the issue he was describing isn't something you need to worry about.

That said,

dozens of thousands of pages I must to pass to the server via AJAX

is a pretty odd requirement and will require a lot of bandwidth even if you don't overload the network. Consider if there's any more elegant solutions to the problem, such as generating/sending a page only when that page is requested.

来源：https://stackoverflow.com/questions/61725911/multiple-ajax-calls-via-recursive-function-and-ddos-ing-ourselves