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 ‘Conferences’ 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 »

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 »

FreePascal downloads I used to get Web Service Toolkit to compile since the Delphi WSDL importer has braindead include support

Posted by jpluimers on 2020/09/11

The Delphi WSDL importer maintenance has been in dormant mode for a long while, which means it still barfs on WSDL include directives.

In the day and age of REST and gRPC, I don’t think it will get any love soon.

Related bug entries are for instance RSP-18630: WSDL generate bad code and RSP-17321: “Import WSDL” generates invalid code without explanation of problem are examples of this, and I’m sure that QC had more if it were still alive; I could find these in the WayBack machine:

The problem manifests itself when the WSDL file includes one or more XSD files. The generated code will contain a section like this:

  // ************************************************************************ //
  // The following types, referred to in the WSDL document are not being represented
  // in this file. They are either aliases[@] of other types represented or were referred
  // to but never[!] declared in the document. The types from the latter category
  // typically map to predefined/known XML or Embarcadero types; however, they could also 
  // indicate incorrect WSDL documents that failed to declare or import a schema type.
  // ************************************************************************ //

Further below is a series of commented out types, all starting with a ! end ending in a column with the namespace of those types.

Searching for the first line gives numerous examples as far back as Delphi 7, for instance:

Based on those, I think the reason is that the WSDL importer fails on <soap:binding transport="http://schemas.xmlsoap.org/soap/http" style="document" /> which is quite common in the real world.

I did not want to pursue manually modifying the WSDL file, or manually generating the types as the WSDL and XSD files were prone to changes and manual steps would make the re-import process more tedious. If you do want to do that, these link might help:

This is what I used to get this to compile and run [WayBack] Web Service Toolkit – Free Pascal wiki:

Build steps

FPC installation

  1. Run the 32-bit installer
  2. Keep all options except on the second install screen, disable Associate .inc files with FreePascal IDE
  3. Add C:\FPC\3.0.4\bin\i386-win32 to the user path

Building

  1. Recursively unzip wst-0.7u.zip
  2. Open a command prompt in the wst-0.7u directory
  3. Verify there is a ws_helper subdirectory
  4. …
  5. …
  6. …
  7. …

When compiling in Delphi, then you definitely need the FreePascal RTL sources for the PasTree unit; see [WayBack] fcl-passrc – Free Pascal wiki.

Related:

–jeroen

Posted in Conference Topics, Conferences, Delphi, Development, Event, Software Development | 1 Comment »

Recursive loop, see loop, recursive

Posted by jpluimers on 2020/09/09

Recursion explained visually.

Via [WayBack] Wenn mehrere Generationen in den Feiertag / Vatertag starten.

[WayBack] Original picture at [WayBack] Bug Life | Chickie’s Rides | Pinterest | Vw, Volkswagen and Cars.

–jeroen

 

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

What’s the piece of Delphi knowledge you find yourself looking up over and over again…

Posted by jpluimers on 2020/08/31

From an interesting thread at [WayBack] What’s the piece of Delphi knowledge you find yourself looking up over and over again? For me format strings is probably the thing that most stubbornly… – Lachlan Gemmell – Google+

On the generics side, I have wrote a few bits in my blog before, often pointing to information by others (many by Stefan Glienke as his skills on this topic are beyond excellent):

And on records:

There are some very good books on Delphi though that dig deeper than the documentation:

–jeroen

Posted in Conference Topics, Conferences, Delphi, Development, Event, Software Development | 4 Comments »

Spring4D – Shared, Weak references

Posted by jpluimers on 2020/08/25

In addition to Shared/IShared, there is also Weak/IWeakReference in Spring.pas; these blog post explain more about them:

Related: If you were using Managed / IManaged in Spring4D, be aware they got renamed to Shared / IShared.

–jeroen

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

10 Tips on How to be a Great Programmer – Java, SQL and jOOQ.

Posted by jpluimers on 2020/08/25

Interesting thoughts: [WayBack] 10 Tips on How to be a Great Programmer – Java, SQL and jOOQ.

Via: [WayBack] The bitterness of poor quality remains long after the sweetness of low price is forgotten — Benjamin Franklin (not sure this is true, could not find a source) – Thomas Mueller (dummzeuch) – Google+

–jeroen

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

Current state: still fighting the metastases of the rectum cancer; chemos are done, major liver surgery in about 3 weeks

Posted by jpluimers on 2020/08/23

A long follow-up of Current state: still fighting with rectum cancer, but chances for better quality of life which does not even include everything, because so much happened.

So this is the current state; browse back via Twitter for more of the history which you can find at [Archive.is] Jeroen Pluimers on Twitter: “Too much to let sink in …” and [Archive.is] Jeroen Pluimers (@jpluimers) | Twitter.

Read the rest of this entry »

Posted in About, Cancer, Conference Topics, Conferences, Event, Personal, Rectum cancer | 1 Comment »

Delphi unit aliases: multiple ones can point to the same unit

Posted by jpluimers on 2020/08/20

A while ago, I had to figure out how to get some GExperts stuff cross-compile to older Delphi versions, because of UITypes usage that is not available in Delphi XE and lower (but much of what it contains is in the Types unit).

So I went down memory lane, as I remember in Delphi 2, the Delphi 1 WinTypes and WinProcs units were merged into the Windows unit.

A quick search revealed the stackoverflow entry mentioned here:

for the Delphi 1 -> Delphi 2 migrations, these aliases were used where multiple units pointed to the same one:

WinTypes=Windows;WinProcs=Windows;DbiProcs=BDE;DbiTypes=BDE;DbiErrs=BDE

See [WayBack] delphi – wintypes.dcu not found and code completion stops working – Stack Overflow

A longer search found this in my own archives:

File D2-CS-2.0\DEMOS\DOC\AUTOPROJ\AUTOPROJ.DOF

Has this line:

UnitAliases=WinTypes=Windows;WinProcs=Windows

Source: [WayBack] GX_GenericUtils.pas fails to build in Delphi 2007 because it uses unit UITypes · Issue #22 · jpluimers/GExperts · GitHub

(Ab)using unit aliases to fail on VCL

You can use unit aliases so your applications cannot use the VCL any more.

The trick is to alias Forms or VCL.Forms into something that does not exists, like Forms=__no_VCL_Forms__. The reason this works is that any VCL application uses the Forms unit because of the Forms.Application variable.

Reference:

–jeroen

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

Happy birthday UDP!

Posted by jpluimers on 2020/08/20

Today it’s the 40th birthday of UDP. Or more precise: 40 years after [WayBack] RFC 768 – User Datagram Protocol got submitted.

It is still used a lot today, so be sure to read more background on [WayBack] User Datagram Protocol – Wikipedia.

And of course on a birthday, it is nice to have few good jokes. So here we go:

[WayBack] “I would tell you a joke about UDP, but you probably wouldn’t get it.” | Hacker News

[WayBack] I would tell you a joke about UDP, but you probably wouldn’t get it. So here’s a TCP joke | reddit.

[Archive.is]:

  • UDP packet bar walks into
  • The best thing about UDP jokes is that I don’t care if you get it. #sysadmin #IT

You can generate more yourself: udpjoke.py

–jeroen

Read the rest of this entry »

Posted in Communications Development, Conference Topics, Conferences, Development, Event, History, Internet protocol suite, UDP | Leave a Comment »

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