Yaron

I eventually created an auto-executing HTML form and used TWebBrowser.LoadFromStrings() to load the HTML and automatically login.

I even made the login 'pretty' by having the form hidden and showing a logo with a CSS based "processing" animation.

The end result looks smooth & professional.

I'm wondering if there's a release date planned, I hate installing Delphi each time, takes a while to get everything re-configured on a clean install and doing in-place upgrades has been hit & miss for me.

Even though I have a subscription, I did not receive an invitation and now I have a quick Android project that I wanted to beta-test through the play store and... impossible.

While this is a small hurdle now, there are projects that are due in a month or two that I simple can't release, it doesn't seem like google is accepting exemptions on new projects.

I'm doing something similar and encountered some of the same issues.

1. Since ISAPI is a DLL, did you add "IsMultiThread := True;" to let the memory manager know this DLL is using multiple threads (otherwise you can get random-seeming crashes)?

2. I'm not sure your logging code is thread safe, it might be useful to add a critical section to your log writes.

3. There should be no problem using global read-only variables across threads as long as these variables are not classes that do things in the background.

4. If you're accessing a database, make sure to use connection pooling.

5. Do you get a ~90sec freeze when trying to stop the application pool? Make sure to terminate the ISAPI dll correctly.

This is my original thread in which the nice people of this forum helped me identify some of these issues:

15 minutes ago, TomDevOps said:

Now I don't get this - why do you want to login this way? Why you do not want to use REST and login that way? I do not know if WebView allow to execute your own JavaScript - if so, you could pass credentials to the form this way and then call submit, but again, I would not do this way.

 

I try to understand your architecture and design choices, can you elaborate, please?

I believe I might be able login by using LoadFromStrings() to feed the html form and auto-activating JS to TWebBrowser with the form's action set to my login url, which will bypass the need to actually modify the html content.

3 minutes ago, TomDevOps said:

I think I know what you want to achieve, I understand that you want to have HTML/CSS/JS to avoid designing for each platform, so make everything in React, then your web-app and mobile-app can share HTML/CSS/JS stuff 🙂 

 

If React is not an option, then use REST for communication and WebView for displaying the results only, this is what I did for one of the app.

I have already written a Delphi ISAPI DLL that hooks into the microsoft IIS server and outputs HTML/JS/CSS.  That part is done and working well in all browsers.

Now, for convenience  I would like to create a separate Android app (using Delphi) that uses the TWebBrowser component to open the web server's URL and automatically log-in by filling in the html form fields (user/pass) and press the "submit" button.

With this second part I'm struggling since I don't know how to get to the HTML content displayed by the TWebBrowser component and how to trigger the form's "submit" button.

7 minutes ago, TomDevOps said:

Should not you use ReacjNative then instead of FireMonkey?

 

I'm not sure I understand you, do you mean to write the Android app in ReactNative instead of Delphi?

I don't have any experience with ReactNative, that's why I'm trying to use Delphi to simply wrap the html generated by my back-end code in a TWebBrowser component.

21 minutes ago, Remy Lebeau said:

A better solution would be to forgo the TWebBrowser frontend altogether and redesign your web app to accept REST requests on the backend server to do the work you need.  Then use a standard UI on the client side to display the results as needed.

You would have to check if the underlying platform browsers provide any APIs to automate them in code.  VCL's TWebBrowser is a wrapper for Internet Explorer and exposes access to its DOM API.  FMX's TWebBrowser does not expose similar functionality.

The Delphi back-end is already rest-based, but the whole point of using HTML/JS for the front-end is to avoid having to design the UI for each platform (web/desktop/android) and rely on CSS to style the UI for every device without having to deal with device resolution/scale within Delphi code.

I wrote a web-facing application that uses a combination of javascript/css/html for the front-end and Delphi for the back-end.

I decided to create a simple Android app that would wrap the web application using a TWebBrowser control that automatically navigates to the web application's URL.

The web application's requires a login and once logged in, a token is generated sever-side and then embedded into the html of subsequent server requests for future authentication.

For security reasons, I do not want to store the code used to create the token within the Android app, so the easiest way for me to perform the login would be to automatically fill in the web form fields and simulate a "submit" action.

Searching the web, I only found examples of how to do this using the WinAPI version of TWebBrowser, but I'm trying to write something that will work on Android and possibly iOS, any ideas?

You beat me to it, I just found this:
https://mathiaspannier.wordpress.com/2016/07/17/how-to-properly-cleanupshutdown-a-delphi-isapi-which-uses-threads/

Which is essentially the same answer, can't close the connection in the finalization section when dealing with ISAPI.

Looks like I'm encountering an IIS issue when using this scheme.

In the ISAPI's DLL's finalization code I call "FDManager.Close" and in IIS, when stopping the application pool associated with the DLL it can take ~60 seconds before I can restart the pool, any ideas?

This is the error I get:

Quote

 

---------------------------
Cannot Start Application Pool
---------------------------
There was an error while performing this operation.

 

Details:

The service cannot accept control messages at this time. (Exception from HRESULT: 0x80070425)

 

When checking my logs, It doesn't seem to exit cleanly (the debug message that the "DB Closed" does not show up in the log), but there doesn't seem to be an exception, here's the code I use:

  Try FDManager.Close; Except
    on E : Exception do {$IFDEF TRACEDEBUG}AddDebugEntry('Exception disconnecting from DB : '+E.Message){$ENDIF};
  End;
  {$IFDEF TRACEDEBUG}AddDebugEntry('DB Closed');{$ENDIF}

When I run the same code locally as an EXE that handles the HTTP requests, there are no issues, any ideas?

Thank you!

Took me a bit to understand the mechanics, but with your help I managed to rewrite the code with minimal changes and so far it's working.

P.S.

"FDManager.Active :=True;" no longer works in Delphi 10.3, it simply doesn't exist anymore, but "FDManager.Open" seems to be the replacement.

3 hours ago, Jacek Laskowski said:

In multithread application you must use separated connection per thread.

Does that mean that for every http request (that requires DB access) I have to create a new instance of TFDConnection and then connect to the DB?

This is the first time I'm writing an ISAPI dll with DB access and the threading model is not exactly clear to me.

My original (perhaps flawed) assumption was that IIS will load additional DLLs in separate threads to handle concurrent http requests.

I would like to avoid the 100ms penalty for connecting to the DB on each request, any tips?

I am trying to build a system that will handle concurrent DB requests efficiently, there's not a lot of load, but it should be able to handle more than 1 query concurrently.

I am using FireBird v3.0.4 and Delphi 10.3.2 with the TFDConnection component.

I am hosting the code in an ISAPI DLL that runs on IIS 7.5.

Right now I'm creating the DB connection using TFDConnection in the DLL's "initialization" section.

However, I noticed that even under low-load (2-3 users), I occasionally get an "[FireDAC][Phys][FB]Error reading data from the connection." exception when performing a DB query (not the same DB query, it seems pretty random).

I tried to research the error and didn't find anything clear, the best I got was :

https://forums.embarcadero.com/thread.jspa?threadID=245750

Which seems to indicate that I should instance a copy of TFDConnection for every query.

Before I make significant code changes to test this, I would welcome any tips on the best approach to handling DB concurrency.

57 minutes ago, rvk said:

Any reason to prefer nbackup above gbak?

Not my quote:

Quote

 

nbackup is a new backup utility that comes with Firebird 2.0. It offers possibilities not present in gbak - Firebird's pre-existing backup tool - but doesn't replace the latter. Both programmes have their strengths and weaknesses; they will likely coexist for some time to come.

 

I basically used it cause that's the example I was able to find in the documentation for exporting the DB.

1 hour ago, Cristian Peța said:

Was Task Scheduler not good enough for this?

In theory I could have used the windows task scheduler, but I needed more control and I'm using the service to perform other timed DB actions.

And I couldn't just call nbackup directly from the task scheduler as I'm erasing old DB files and numbering new backups based on existing backup file names (a running counter in the file name) and some more logic is required for this.

3 hours ago, ertank said:

In case you are taking your off-site backups on a Linux server, you might want to have a look at scp (Secure Copy). On Windows there is Putty which is free and has pscp.exe doing same job.

 

 

 

SyncThing has a Linux/Mac/FreeBSD/etc... client, so in theory the off-site backups can be on pretty much any widely used OS.

It took me hours of research to find the tools & documentation and haven't found any up-to-date text describing a similar process, so I decided to post my findings here in case someone else has the same requirement.

I wrote (in Delphi) a simple windows service that runs the FireSQL "nbackup.exe" command line tool to create a DB backup every [x] hours using this command line:

"c:\Program Files\Firebird\Firebird_3_0\nbackup.exe" -U SYSDBA -P [password] -B 0 "c:\path\database.FDB" "[output_file]"

The windows service keeps [x] number of backup files (erasing old files) and creates a new backup every [y] minutes.  Personally, I used 1 full-db backup per hour, covering an entire week (168 files).

I then use the open-source SyncThing P2P file sync tool (also running as a windows service) to securely & automatically sync the DB backups with every PC assigned as off-site backup.

100% automated, secure, zero cost.

This is a bit old, but I've been blocking the windows screen-saver for media playback in every version of windows since 1999.

I'm actually handling several actions, first I capture the WM_POWERBROADCAST message in the form:

procedure WMPOWERBROADCAST(var M : TMessage); message WM_POWERBROADCAST;
const
  PBT_APMQUERYSUSPEND       = $0000;
  PBT_APMQUERYSTANDBY       = $0001;
  PBT_APMQUERYSUSPENDFAILED = $0002;
  PBT_APMQUERYSTANDBYFAILED = $0003;
  PBT_APMSUSPEND            = $0004;
  PBT_APMSTANDBY            = $0005;
  PBT_APMRESUMECRITICAL     = $0006;
  PBT_APMRESUMESUSPEND      = $0007;
  PBT_APMRESUMESTANDBY      = $0008;
  PBT_APMBATTERYLOW         = $0009;
  PBT_APMPOWERSTATUSCHANGE  = $000A;
  PBT_APMOEMEVENT           = $000B;
  PBT_APMRESUMEAUTOMATIC    = $0012;
begin
  Inherited;
  Case M.WParam of
    PBT_APMQUERYSUSPEND,
    PBT_APMSUSPEND       :
    Begin
      If SystemSuspended = False then
      Begin
        SystemSuspended   := True;
      End;
    End;
    PBT_APMRESUMEAUTOMATIC :
    Begin
      SystemSuspended := False;
    End;
  End;
  M.Result := Integer(True);
end;

Then on WinMsg (Application.OnMessage := WinMsg;) I do:

procedure TMainForm.WinMsg(var Msg: TMsg; var Handled: Boolean);
var
  ModWnd : HWnd;
  I      : Integer;
  mPos   : TPoint;
begin
  If (Msg.Message = SC_SCREENSAVE) or (Msg.Message = SC_MONITORPOWER) then
  Begin
      Msg.wParam  := 0;
      Msg.Message := SC_Move;
      Handled     := True;
  End
    else
  If (Msg.Message = WM_SYSCOMMAND) then
  Begin
    Case Msg.WPARAM of
      SC_MONITORPOWER,
      SC_SCREENSAVE    :
      Begin
          Msg.wParam  := 0;
          Msg.Message := SC_Move;
          Handled     := True;
      End;
    End;
  End;
End;

Then on WndProc ( procedure WndProc(var Msg : TMessage); override;) :

Quote

 

procedure TMainForm.WndProc(var Msg : TMessage);

begin

  If Msg.Msg = WM_SYSCOMMAND then
  Begin
    {$IFDEF LOCAL}
    //If Msg.WParam and $FFF0 = SC_MAXIMIZE then ShowMessage('maximized');
    {$ENDIF}
    If ((OPOTScreenSaver = True) and (plState <> stClosed) and (MainForm.WindowState = wsMaximized)) or (OPScreenSaverAW = True) then
    Begin
      Case Msg.WParam and $FFF0 of
        SC_SCREENSAVE,
        SC_MONITORPOWER :
        Begin
          Msg.Result := 0;
        End;
        else inherited WndProc(Msg);
      End;
    End
    Else inherited WndProc(Msg);
  End
    else
  If (Msg.Msg = SC_SCREENSAVE) or (Msg.Msg = SC_MONITORPOWER) then

  Begin

    Msg.Result := 0;

  End
  Else inherited WndProc(Msg);
End;

 

 

 

Hope this helps.

Took your advice and created a QC report:

https://quality.embarcadero.com/browse/RSP-26253

It's not an issue restoring the IDE, just a little drag on that line, but it happens about once or twice every day which is a bit annoying.

To give me the largest work-space, I designed the Delphi IDE UI to look like the attached "delphi_before.jpg".

However, under some conditions, windows throws apps a resize event (e.g. when turning on a secondary monitor), and then the Delphi IDE UI automatically changes to the attached "delphi_after.jpg" (the tool-bar drops down a row).

Is there any way to lock the UI so my preferred layout remains fixed?

P.S. This is on Win7 64bit.

Nevermind, I figured it out, I had to move the charset code after setting the email body.

Another bit of information, when looking at the headers of the delivered email, there's this:
Content-Type: text/html; charset=us-ascii

Even though CharSet is set to UTF8.

According at this post https://stackoverflow.com/questions/9844250/not-able-to-send-utf-8-email-using-delphi-indy , I'm setting the parameters in the right order.

If I try to use UTF8Encode in Delphi 10.3 I get a warning "[dcc32 Warning] xxx.pas(683): W1057 Implicit string cast from 'RawByteString' to 'string'".

Using Delphi 10.3.2:

I use the function below to send HTML eMails through Amazon SES using Indy.

However, no matter what I tried, non-latin characters appear as "�" (for example, instead of "Oriënt Express", gMail displays "Ori�nt Express").

I need to  be able to include non-latin characters in both the subject and the eMail's HTML body, what am I doing wrong?

P.S.

Not sure if it matters, but the HTML does contain "<meta charset="UTF-8">" in the "<HEAD>" block and I verified the source was properly encoded by saving it to a local utf8 html file which displays the encoded characters correctly.

procedure SendEmailIndy(
        const SMTPServer: string;
        const SMTPPort: integer;
        const SMTPUserName : string;
        const SMTPPassword : string;
        const FromName, FromAddress: string;
        const ToAddresses: string; //comma "," separated list of e-mail addresses
        const CCAddresses: string; //comma "," separated list of e-mail addresses
        const BCCAddresses: string; //comma "," separated list of e-mail addresses
        const Subject: string;
        const EmailBody: string;
        const IsBodyHtml: Boolean; //verses Plain Text
        const Attachments: TStrings;
              UseTLS : Boolean);
var
    smtp: TIdSMTP; // IdSmtp.pas
    TLSHandler : TIdSSLIOHandlerSocketOpenSSL; // TLS support
    msg: TidMessage; // IdMessage.pas
    builder: TIdCustomMessageBuilder; //IdMessageBuilder.pas
    s: string;
    emailAddress: string;
begin
  TLSHandler := nil;
  msg := TidMessage.Create(nil);
  msg.ContentType := 'text/html';
  msg.CharSet     := 'UTF-8';
  msg.ContentTransferEncoding := '8bit';

  try
    if IsBodyHtml then
    begin
      builder := TIdMessageBuilderHtml.Create;
      TIdMessageBuilderHtml(builder).Html.Text := EmailBody;
    end
      else
    begin
      builder := TIdMessageBuilderPlain.Create;
    end;

    try
      Try
        if Attachments <> nil then for s in Attachments do builder.Attachments.Add(s);
        builder.FillMessage(msg);
      Except
        on E : Exception do {$IFDEF TRACEDEBUG}AddDebugEntry('Exception : '+E.Message){$ENDIF};
      End;
    finally
      builder.Free;
    end;

    msg.From.Name    := FromName;
    msg.From.Address := FromAddress;
    msg.Subject      := Subject;

    //If the message is plaintext then we must fill the body outside of the PlainText email builder.
    //(the PlainTextBuilder is unable to build plaintext e-mail)
    if not IsBodyHtml then msg.Body.Text := EmailBody;

    for s in ToAddresses.Split([',']) do
    begin
      emailAddress := Trim(s);
      if emailAddress <> '' then
      begin
        with msg.recipients.Add do
        begin
          //Name := '<Name of recipient>';
          Address := emailAddress;
        end;
      end;
    end;

    for s in CCAddresses.Split([',']) do
    begin
      emailAddress := Trim(s);
      if emailAddress <> '' then msg.CCList.Add.Address := emailAddress;
    end;

    for s in BCCAddresses.Split([',']) do
    begin
      emailAddress := Trim(s);
      if emailAddress <> '' then msg.BccList.Add.Address := emailAddress;
    end;

    smtp := TIdSMTP.Create(nil);
    try
      smtp.Host     := SMTPServer;
      smtp.Port     := SMTPPort;
      smtp.Username := SMTPUserName;
      smtp.Password := SMTPPassword;

      If UseTLS = True then
      Begin
        TLSHandler     := TIdSSLIOHandlerSocketOpenSSL.Create;
        smtp.IOHandler := TLSHandler;
        smtp.UseTLS    := TIdUseTLS.utUseRequireTLS;
      End;

      Try
        smtp.Connect;
        try
          try
            smtp.Send(msg)
          Except
            on E : Exception do {$IFDEF TRACEDEBUG}AddDebugEntry('SMTP Send Exception : '+E.Message){$ENDIF};
          End;
        finally
          smtp.Disconnect;
        end;
      Except
        on E : Exception do {$IFDEF TRACEDEBUG}AddDebugEntry('SMTP Connect Exception : '+E.Message){$ENDIF};
      End;
    finally
      smtp.Free;
      If TLSHandler <> nil then TLSHandler.Free;
    end;
  finally
    msg.Free;
  end;
end;