[Lazarus] GUI development for web UI

michael.vancanneyt at wisa.be michael.vancanneyt at wisa.be
Wed Nov 24 17:13:38 CET 2010

On Wed, 24 Nov 2010, Dariusz Mazur wrote:

> W dniu 2010-11-24 10:21, michael.vancanneyt at wisa.be pisze:
>> On Wed, 24 Nov 2010, ik wrote:
>>> Hello List,
>>> Well I know about the framework fur Javascript library in Lazarus, but I'm
>>> thinking in the past year or so, what will it take to design a gui
>>> application using Lazarus, and make it work like a web app that act the 
>>> same
>>> as the desktop version, without any specific components for it.
>>> Then today I found the following link:
>>> http://blogs.gnome.org/alexl/2010/11/23/gtk3-vs-html5/ and it looks like
>>> someone made something like that on GTK3.
>>> The problem is that I do not have the time to do it myself (or I would 
>>> have
>>> created at least the start for it), what will it take to create something
>>> like that for Lazarus that is not dependent on the widgets (it will not 
>>> care
>>> if it's GTK, Qt, WinAPI etc..), and take also 3rd party components for it 
>>> ?
>> You should first answer the question this man asks:
>> "Now, I want to know, Is this useful?"
>> The answer IMHO is: no.
>> Each and every GUI or user action/change/whatnot will result in a request 
>> from the browser to the webserver (with corresponding result sent back), 
>> and will cause a lot of traffic.
>> While this is fine and doable for small apps, it is not scalable at all. If 
>> 100 users use your system, it will crash under the load (if not earlier).
> That's not true. Transfer every action to server is very simple task, and 
> computing results also. Thus (on my web app) it took less than 10ms and every 
> user very rare generate more actions than 1 per second.  Computing and 
> sending pdf reports took much more (more than 90% of working time). As I 
> observe two on core machine can work 100 users concurent without problem. 
> With more can be problem, but  with memory.

Yes, I remember my discussion with you. I also remember that the round 
trip time I observed is over 100 ms, which is noticeable. 
(maybe not on intranet, but definitely on internet)

Secondly, you have not very demanding users and/or GUI, it seems :-)
I'll describe an interface which I currently have: A grid with about 
600 checkboxes (don't ask why, they want it so).  Users click the 
checkboxes in rapid succession, thus generating much more than 1 
event per second.

But if you believe in it: why not cooperate with the Lazarus team and
create a web widget set ? All options must be explored, you obviously 
have a good basis for it, so why not share it ?


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