On Mon, 30 Mar 2009, Dariusz Mazur wrote:
> Michael Van Canneyt pisze: > > > > > > I just want to make them in pascal and keep the codebase and know-how I > > > > have > > > > in my team. > > > > > > > > > > > As I. I want (i;ve done succesfully) reuse 90% of desktop code in > > > webbased. > > > But you want to rewrite quite huge part to JS. Why? What for. > > > > > > > Because some of the (rather complex) business logic must be in the client to > > make it respond as a desktop application. > > > > A simplified example: 2 sets of data. 2 comboboxes. User chooses from set 1 > > in combobox 1. Based on his choice, the data in the second checkbox must be > > filtered. This must be done without round-trip to the server, because the > > data 2 set is large, and combobox 1 is used often. So I need some part of > > the business logic (complex relation between items in 2 sets of data) on the > > client. > > > I don't agree. Only one requirement should be fulfill, respond in reasonable > time, say less than 500ms. 500 ms is WAY too slow. > My way: only visible rows are send to browser, say 30 rows, they took about > 3kb, time 3ms in LAN, 100ms when server is on second side of world. Rendering > 100..300ms, on slow browser maybe longer. Even it it will be done after each > of user action its no problem for server neither rest of infrastructure. On > application side: its no matter that is desktop or web based, events and > response are the same. Nono. We're not talking about 30 rows, more like 5000-7000. Transmitted once, when the window is opened. That the window is slow to open initially is OK, but once opened it should work lightning fast for the duration of use. I simplified it a bit, but it is a real life example. > Your way: first transmit whole database to browser, JS compute what part > should be display. When set of date is bigger you can send partial. But after > select combobox all data must be send to compute filtering. On slight set it > may work, but not on big. > But even on small sets of data time of response will be notable (I've seen > ExtJS demo, its only on browser side, and its work rather slow, can you > expect, that most of your code will have better optimization) I've seen it in action in Morfik, and it works fast. > And what about transfer tons on JS to browser? Ah, morfik has a nice thing for this: you can preload forms asynchronously. > > > > > Till now there is no example of any issue, that cant be done without > > > translating pascal to JS without preserve all needs. > > > > > > > > > > If it was up to me, client/server would do the job just fine. But I > > > > cannot > > > > ask all parents of all pupils of all our schools to install a client > > > > application: > > > > a) They don't want it. They are mostly computer agnostic, but they can > > > > surf > > > > the internet. > > > > b) Our helpdesk would find and emigrate to an unknown island somewhere > > > > in > > > > the > > > > south pacific because of the installation and upgrade problems :-) > > > > > > > > > > > I agree. But I think that is new niche (cloud computing) and chance for > > > me. > > > This is quite new opportunities, many approaches , and we should know how > > > choice proper. > > > > > > > As far as I'm concerned, Morfik is the correct approach. If I can do what > > they do in Lazarus and open source: I'm sold. > > > I cant found any site/application prepare by Morfik. Do you know any site, > that I can see it at work. The morfik site itself is the best example. You can also download the chess example. (if it is still available) Michael. _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
