Oliver Morsch
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Posts posted by Oliver Morsch
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This is not thread safe !!!. (session list ist a global var and there is no access control, ... )
Better you store a reference to your DataModule in a Field of TUniMainModule. That would be easy to read/write - no thoughts about sessions and threads, because thread safe and per session by default.
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You have the same problem if you are using delphi/firemonkey for programming android: there are no blocking calls (showmodal, message Dialog, ...).
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#2
Use "free form" and you are free...
UniGui forms that are not in use (displayed) will be freed for less memory consumption. If you show you them later again they are created again, but so prior changes are lost.
#4
That is how HTTP works: Server can only answer a request - if there is no request, there will be no answer.
#5
Not every keystroke or mouse move will be sent by default. Would be too much traffic.
If you can use such high traffic depends on your own system. Do you have view users in a local network, there should be no Problem. Do you have many users over (slow) internet connection, there is a Problem In second case you should use (client side) JavaScript...
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#1:
You have "Free Form" and "UniGUI managed Form". Free Form you must create/free by yourself, you can have more than one instance of it per session at a time. With UniGui Form you have only one per session, create and free will be done by uniGUI. accessing the form (function) will create it, close will free it. The difference to Delphi/VCL is that it can't use global vars for that, because each user/session wants its own instance. So there is a function "MyForm" that delivers the instance for the current session (including create when needed).
#2:
So that auto create (on access and show) and auto free (on Close) works correct.
#3:
See #1. And be aware that you do not use global vars.
#4:
UniTimer fires on client side (browser). That is needed, because browser must first send a request, otherwise Server could not answer (send something to browser).
#5:
So every key press is send to the Server -> much traffic. You can use Client Events (JavaScript in browser) and then use AjaxRequest(...) when you must process something on Server.
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There are 347 downloads - and no bug reports till now...Rav, on 02 Jul 2015 - 11:33 PM, said:
I looked through your long polling application, very informative, thank you!
I think that's a little bit complicated scheme, does it have flaws?
No.Rav, on 02 Jul 2015 - 11:33 PM, said:
Are you planning to add WebSockets example to it?
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As far as I understand the TUniTimer being placed on the main form is instantiated in every session,
Yes.
so with the 100 open sessions we'll have 100 timers on the server side.
No. TUniTimer runs/fires on client side (browser). But for every "onTimer" the browser sends a request to ther server. So you have very much network trafffic and the server must handle all these requests.
Is this the right way of constructing the application?
In my opinion: No. See option 2 and 3 in Post #4.
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In other words the clients display some server info and can modify some server parameters remotely.
When the server parameter is changed (it could be also done due to other internal reasons) the server sends
a message (delphi record) to all clients, they receive it and update the display info accordingly.
By default web servers can't send messages to (all) clients. Servers can only answer a request.
So you can do one of the following;
- using TUniTimer (client (browser) sends every x seconds a request for updates to the server)
- using "web sockets" (HTML5)
- using "long polling" (see here)
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Please check the working directory in isapi mode -> The search path for the dll could be the iis/apache directory instead your app directory.
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But you can show a VCL form with a TWebBrowser in it. So it looks like a standard program (with a web gui).
- create a normal VCL (not UniGUI !) form in your project that is shown at startup
- put a TwebBrowser onto this form (Align: alClient)
- onFormShow: WebBrowser.Navigate('http://localhost:8077/');
onFormClose: Applicatin.Terminate; // shuts down server if form is closed
To use a new browser version that works with UniGUI you must must add a registry entry or change !DOCTYPE (second I don't know how doing in UniGUI, but first works for me)
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You are not alone -> Windows 8.1 Pro + IE11
Chrome is OK.
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With http://wkhtmltopdf.org/ you can convert html to a pdf or image on server side.
But if you use image:
- the size will be big
- you can't search for text in PDF
- the font will not scale (can look terrible)
But you can make the complete report with html and then use wkhtmltopdf or you make 2 PDFs (from report and html) and then merge them.
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For our current project we probably will end up writing our own javascript code to allow the user to choose files and to perform uploads.
Have you seen this?
http://forums.unigui.com/index.php?/topic/2490-multiple-file-upload/
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You can access content of TUniUrlFrame (= iframe) only if the content uses the same server and port as your webapp, otherwise it it is blocked by the browser (security issue).
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Instead of
ExtractFilePath(Application.exeName)
What is the difference ?
If you use ISAPI-DLL this could be another path (not dll path).
3. To retrieve (client side) DeskTop directory, can i use
In MainModule :
GetSystemPath(CSIDL_DESKTOPDIRECTORY)) ?
You cannot get/access folders of the client (in a browser window).
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About thread handling in UniGui: it is simple!
Don't use global vars, instead of that use fields/properies (in the form-/module-/anyOther-class definition)
Then each session accesses only objects in its own thread (controled by UniGui) and you never read/write memory used by other sessions. Each session has ist own instances of all.
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Hi,
i use this sample camera code. but i can not save cam photo.
how i can on canvas picture save?
thanks
See here:
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@ Oliver: sorry, can you rephrase?
Farshad wrote in post #2:
OnException event is only for non-visual code.
ShowMessage() and etc. will not work here.
...
I think ServerModule is another thread/context and something like ShowMessage() there will produce other problems.
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Use a text like this:
<span onclick="alert(123)">Edit</span>
Instead of "alert(123)" you must use "ajaxRequest(...)"
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Read post #2 from Farshad ?!
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How could I send the image to server or a dataset (BLOB Field)?
see here:
http://forums.unigui.com/index.php?/topic/2490-multiple-file-upload/?p=11814
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LoginString := 'SELECT * FROM tbluser ';
LoginString := LoginString + 'WHERE login = ' + #39 + (edtLogin.Text) + #39;
LoginString := LoginString + ' AND password = ' + #39 + (edtPassword.Text) + #39;
And the password is:
' or '1'='1
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TDataModule - To use or NOT to use
in General
Posted
Additional you can use a (your) function "FDataModule" in your DataModule as follows:
function FDataModule: TFDataModule;
begin
result := uniMainModule.FDataModule;
end;
Instead of "uniMainModule.FDataModule" you could you use a (String)List/Array/HashMap/... as UniMainModule field with containing all datamodules for the current session; so you have not to declare something for each of your modules in UniMainModule.