[PATCH 14 of 20] hgweb: add ajaxScrollInit skeleton

[Alexander Plavin]

10.08.2013, 17:22, "Laurens Holst" <laurens.nospam at grauw.nl>:
> Op 09-08-13 20:57, Alexander Plavin schreef:
>
>>  # HG changeset patch
>>  # User Alexander Plavin <alexander at plav.in>
>>  # Date 1376061308 -14400
>>  #      Fri Aug 09 19:15:08 2013 +0400
>>  # Node ID f28ca736646cf582ef71b518b995a1d63c40849a
>>  # Parent  015d43fca74b12c5c79ca14683d375dc9675fdd2
>>  hgweb: add ajaxScrollInit skeleton
>>
>>  This piece of code handles onscroll event and makes request to load next page
>>  of entries, but doesn't actually add the loaded entries to the DOM tree yet.
>
> If I look at the bottom of the shortlog (e.g.
> http://hg.plav.in/hg/shortlog/1215bf60468f), every time I scroll down it
> keeps loading even though there is nothing to see anymore.

By 'scrolling down' you mean 'scrolling a bit up and then down', right? :) As you can't scroll down after the end of the page.

>
> Worse, even when scrolling by a few pixels it fires up multiple
> requests. That’s a good way to get DoSsed :).

No new requests are issued while the already sent one hasn't completed, so there are no more than one request active at a time (and they aren't queued, just discarded).

>
> You should stop loading more entries when there aren’t any more to display.

Althrough it doesn't seem like a server performance/security/DoS issue for me, I'd agree to you here: users can think that the list just isn't loaded further due to error, and not due to its end.

>
>>  diff -r 015d43fca74b -r f28ca736646c mercurial/templates/static/mercurial.js
>>  --- a/mercurial/templates/static/mercurial.js Fri Aug 09 22:48:44 2013 +0400
>>  +++ b/mercurial/templates/static/mercurial.js Fri Aug 09 19:15:08 2013 +0400
>>  @@ -364,3 +364,38 @@
>>            element.innerHTML += html;
>>        }
>>    }
>>  +
>>  +function ajaxScrollInit(urlFormat, lastHash, container) {
>>  +    updateInitiated = false;
>>  +
>>  +    window.onscroll = function () {
>>  +        if (updateInitiated) {
>>  +            return;
>>  +        }
>>  +
>>  +        var scrollHeight = document.documentElement.scrollHeight;
>>  +        var clientHeight = document.documentElement.clientHeight;
>>  +        var scrollTop = document.body.scrollTop
>>  +            || document.documentElement.scrollTop;
>>  +
>>  +        if (scrollHeight - (scrollTop + clientHeight) < 50) {
>>  +            updateInitiated = true;
>>  +
>>  +            makeRequest(
>>  +                format(urlFormat, {hash: lastHash, params: 'ajax=1'}),
>>  +                'GET',
>>  +                function onstart() {
>>  +                },
>>  +                function onsuccess(xml) {
>>  +                },
>>  +                function onerror(errorText) {
>>  +                },
>>  +                function oncomplete() {
>>  +                    updateInitiated = false;
>>  +                }
>>  +            );
>>  +        }
>>  +    };
>>  +
>>  +    onscroll();
>>  +}
>>  _______________________________________________
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>>  Mercurial-devel at selenic.com
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>
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