The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘Software Development’ Category

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Delphi Gem of the day: putting “reintroduce” on a destructor. destructor…

Posted by jpluimers on 2020/09/22

A nice thread with examples of all the things you should not do with the Delphi reintroduce keyword:

[WayBack] Delphi Gem of the day: putting “reintroduce” on a destructor.     destructor Destroy(); reintroduce; overload; In our case all we got was a memory lea… – Moz Le – Google+

The problem is that in the original (archived) documentation, not much waring is given around using reintroduce; it is merely posted as solving a nuisance to absolve a compiler warning.

When using it though, all your alarm systems should go off at their highest level as you break polymorphism, but through careful language usage, the pattern you hide can still be used.

One day I will write a longer blog article on this.

Documentation:

A decade of progress has not changed much on this documentation apart from some nicer formatting:

–jeroen

Posted in Conference Topics, Conferences, Delphi, Development, Event, Software Development | Leave a Comment »

7 Rules for Creativity Managers – YouTube

Posted by jpluimers on 2020/09/18

Interesting video explaining there is a lot of work to do around me, meaning I probably need more in stead of less people around me (:

  • Nurture diversity: Creativity managers dislike brains being the same.
  • Create markets: Creativity managers favor coopetition in networks.
  • Rely on merits: Creativity managers embrace networks and gameplay.
  • Make no predictions: Creativity managers keep many options open.
  • Update the workplace: Creativity managers work the environment.
  • Change constraints: Creativity managers optimize for exploration.
  • Open boundaries: Creativity managers connect instead of protect.

Via [WayBack] 7 Rules for Creativity Managers – Marjan Venema – Google+ (who is a great coach).

–jeroen

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Posted in Agile, Development, LifeHacker, Power User | Leave a Comment »

Delphi: TInvokableClassRegistryHelper.GetInterfaceNamespace as the opposite of TInvokableClassRegistry.RegisterInterface

Posted by jpluimers on 2020/09/17

A while ago, I needed the opposite of InvRegistry.RegisterInterface(TypeInfo(MySoapInterfacePortType, 'urn:myURN', 'utf-8');, so instead of registering an interface with a namespace URN, obtain the URN by passing the interface inverting [WayBack] TInvokableClassRegistry.RegisterInterface.

This is the class helper I wrote:

type
  TInvokableClassRegistryHelper = class helper for TInvokableClassRegistry
  public
    function GetInterfaceNamespace(Info: PTypeInfo): string;
  end;

function TInvokableClassRegistryHelper.GetInterfaceNamespace(Info: PTypeInfo): string;
var
  InfoGuid: TGUID;
begin
  // call like `Result := InvRegistry.GetInterfaceNamespace(TypeInfo(MySoapInterfaceType));`
  InfoGuid := GetTypeData(Info)^.Guid; // uses TypInfo; see https://stackoverflow.com/questions/8439246/is-it-possible-to-get-the-value-of-a-guid-on-an-interface-using-rtti
  Result := GetNamespaceByGUID(InfoGuid);
end;

It would have been a lot easier if TInvokableClassRegistry.GetIntfIndex has been public, because then [WayBack]TInvokableClassRegistry.GetRegInterfaceEntry could have been used.

–jeroen

Posted in Conference Topics, Conferences, Delphi, Development, Event, SOAP/WebServices, Software Development | Leave a Comment »

FireDAC can do DBMS back-end conditional SQL via Conditional Substitution

Posted by jpluimers on 2020/09/17

Though the field-types mentioned in the problem and solution are equal (so either is wrong), the solution in [WayBack] I have a little problem with FireDAC and the TStringField and TWideStringField design time generation… – Juan C. Cilleruelo – Google+ pointed out by Jeff Weir is interesting: FireDAC supports conditionals that depend on the DBMS back-end, so you can differentiate between them.

The feature is called Conditional Substitution and has been present ever since AnyDAC (which got bought by Embarcadero, transformed into FireDAC, then after Idera bought Embarcadero, the main developer got pink-slipped).

The AnyDAC documentation is in the wayback machine, though you have to disable the onload event in order to read it.

The [Archive.is] XE5: Preprocessing Command Text (FireDAC) – RAD Studio documentation is not much different from the current state [Archive.is].

More background reading is at [WayBack] www.freepascal.org/~michael/articles/anydac2/anydac2.pdf and Cary Jensen covered it in his 2017 course on FireDAC of which you can see the free ToC.

Example from that thread:

SELECT ART.CD_ITEM                ,
       ART.CD_FAMILY              ,
       ART.CD_CATALOGUE           ,
       CAT.DS_CATALOGUE           ,
       FAM.DS_FAMILY              ,
{IF MSSQL}
       CASE WHEN EXISTS(SELECT 1 FROM CONFIGURATIONS COM WHERE COM.CD_PARENT = ART.CD_ITEM)
          THEN CAST('Y' AS NVARCHAR) 
          ELSE CAST('N' AS NVARCHAR) 
       END HAS_CONFIGURATION      ,
{fi}
{IF FIREBIRD}
       CASE WHEN EXISTS(SELECT 1 FROM CONFIGURATIONS COM WHERE COM.CD_PARENT = ART.CD_ITEM)
          THEN 'Y'  
          ELSE 'N'  
       END HAS_CONFIGURATION      ,
{fi}
       ART.DS_ITEM                ,
       ART.CD_TAX                 ,
       TAX.DS_TAX                 ,
       TAX.PRC_TAX               ,
...

Given the problem statement, the casts likely should have been VARCHAR instead of NVARCHAR, but the construct can be very powerful.

–jeroen

Posted in Database Development, Delphi, Development, Firebird, InterBase, Software Development, SQL, SQL Server | Leave a Comment »

GitHub – gabr42/MultiBuilder: Runs multiple programs in parallel, shows results

Posted by jpluimers on 2020/09/17

Given a Delphi build-VM with enough CPU cores to run many builds in parallel: [WayBack] GitHub – gabr42/MultiBuilder: Runs multiple programs in parallel, shows results.

Much more on this at [WayBack] The Delphi Geek: Introducing MultiBuilder.

Via: [WayBack] Parallel build/test systems made easy(er) – Primož Gabrijelčič – Google+

–jeroen

Posted in Delphi, Development, Software Development | Leave a Comment »

A thread written by @SwiftOnSecurity

Posted by jpluimers on 2020/09/16

[WayBack] A thread written by @SwiftOnSecurity:

Corporate purchasing and policies make funding open source Literally Impossible.

Nothing’s going to change until you make them pay you.

Someone filed a bug?
Support contract.

Someone wants a feature?
Support contract.

It’s literally easier to pay you $1500/yr than $25 once.

Edit: since Threader/Threader_app died, I archived the Twitter thread at Archive.today.

And much more: worth a long read.

Via another interesting post: [WayBack] Idea for FOSS projects. Register your project/product name as a trademark and only use it for official, stable releases. Have a different name for your … – Jan Wildeboer – Google+

Idea for FOSS projects. Register your project/product name as a trademark and only use it for official, stable releases. Have a different name for your not-(yet)-stable Code.

Put trademark agreements in place. Everyone who uses your trademarked name for services based on your code has to pay. Everybody using the non-stable code is free to do so, but cannot use your trademarked name.

With lots of interesting comments:

  • Jan Wildeboer
    +Andreas Kahler because when you don’t allow use without pay you are violating the open source principles.
  • Andreas Kahler
    You just don’t allow the use of the trademarks. That’s perfectly fine with FOSS, e.g. with GPLv3: “you may […] supplement the terms of this License with terms: […] Declining to grant rights under trademark law for use of some trade names, trademarks, or service marks”. See opensource.google.com – Trademarks in Open Source – opensource.google.com
  • Jan Wildeboer+1
    +Andreas Kahler Yep. That’s how we work at Red Hat ;)
  • Alan Cox+1
    It’s how most distros work – it can be a problem though because you then control how the mark is used and without care it becomes a blocker. Eg it’s really hard to ship Unbuntu based stuff because you can’t modify Ubuntu and call it Ubuntu (which is fair enough) , but for cloud images – problem.
  • Jan Wildeboer
    +Alan Cox That’s why it IMHO makes more sense for projects/products.
  • Jan Wildeboer+1
    +Torsten Kleinz … Setting up a new provider at any medium to big company is a big, lengthy and horrifyingly complex process.

–jeroen

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Posted in Development, Open Source, Software Development | Leave a Comment »

Not to self: ERROR_ALREADY_EXIST (183) can also mean your named Mutex already exists

Posted by jpluimers on 2020/09/16

A while ago, I had an error like this when debugging plugins:

Project bds.exe raised exception class EOSError with message ‘System Error.  Code: 183.
Cannot create a file when that file already exists’.

It got was raised when [WayBack] GetLastError returned ERROR_ALREADY_EXIST which according to [WayBack] System Error Codes (0-499) (Windows) has this description:

ERROR_ALREADY_EXISTS

183 (0xB7)
Cannot create a file when that file already exists.

 

The last line is the same description that [WayBack] FormatMessage returns. And it put me on the wrong foot as it wasn’t a file, but a mutex that was created: indeed [WayBack] CreateMutex documents it:

If the mutex is a named mutex and the object existed before this function call, the return value is a handle to the existing object, GetLastError returns ERROR_ALREADY_EXISTS, bInitialOwner is ignored, and the calling thread is not granted ownership. However, if the caller has limited access rights, the function will fail with ERROR_ACCESS_DENIED and the caller should use the OpenMutex function.

In the mean time, the plugin doesn’t raise that as an exception any more.

–jeroen

 

Posted in Development, Software Development, Windows Development | Leave a Comment »

Using Delphi for jiggling the mouse – twm’s blog

Posted by jpluimers on 2020/09/16

To prevent a screen-saver from kicking in [WayBack] jiggling the mouse – twm’s blog:

My solution then is this procedure:

procedure JiggleMouse;
var
  Inpt: TInput;
begin
  Inpt.Itype := INPUT_MOUSE;
  Inpt.mi.dx := 0;
  Inpt.mi.dy := 0;
  Inpt.mi.mouseData := 0;
  Inpt.mi.dwFlags := MOUSEEVENTF_MOVE;
  Inpt.mi.time := 0;
  Inpt.mi.dwExtraInfo := 0;
  SendInput(1, Inpt, SizeOf(Inpt));
end;

Call it in regular intervals and the screen saver will not start.

This is now (or soon will be) in the u_dzOsUtils unit which is part of my dzlib utility library.

–jeroen

Posted in Delphi, Development, Power User, Software Development, Windows | 1 Comment »

Delphi, soap and wrapping values in cdata – Stack Overflow

Posted by jpluimers on 2020/09/15

For my link archive: [WayBack] Delphi, soap and wrapping values in cdata – Stack Overflow

–jeroen

Posted in Delphi, Development, SOAP/WebServices, Software Development, XML/XSD | Leave a Comment »

GitHub – arendst/Sonoff-Tasmota: Provide ESP8266 based itead Sonoff with Web, MQTT and OTA firmware using Arduino IDE or PlatformIO

Posted by jpluimers on 2020/09/15

On my things to try on IoT stuff list: [WayBack] GitHub – arendst/Sonoff-Tasmota: Provide ESP8266 based itead Sonoff with Web, MQTT and OTA firmware using Arduino IDE or PlatformIO

Many Sonoff based devices are never updated, so this firmware will likely be a much more secure solution.

Since it supports MQTT, it should be far easier to integrate into home automation solutions.

Via a comment on [WayBack] +ITEAD Studio has just launched one of the cheapest WiFi smart plug, and it should work in most of the world thanks to 6 different plug types. https://… – Jeroen Wiert Pluimers – Google+

  • How safe would “cheap” be?
  • Linas Naginionis:
    Just flash with Tasmota firmware and you can do whatever you want with it.

The device was announced at

[WayBack] Sonoff S26 WiFi Smart Plug Works in All/Most Countries, Sells for under $10

–jeroen

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Posted in Development, MQ Message Queueing/Queuing, MQTT, Software Development | Leave a Comment »

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