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Our mORMot framework is now able to stub or mock any Delphi interface.

As usual, the best way to explain what a library does is to look at the code using it.
Here is an example (similar to the one shipped with RhinoMocks) of verifying that when we execute the "forgot my password" scenario, we remembered to call the Save() method properly:

procedure TMyTest.ForgotMyPassword;
var SmsSender: ISmsSender;
    UserRepository: IUserRepository;
begin
  TInterfaceStub.Create(TypeInfo(ISmsSender),SmsSender).
    Returns('Send',[true]);
  TInterfaceMock.Create(TypeInfo(IUserRepository),UserRepository,self).
    ExpectsCount('Save',qoEqualTo,1);
  with TLoginController.Create(UserRepository,SmsSender) do
  try
    ForgotMyPassword('toto');
  finally
    Free;
  end;
end;

And... that's all, since the verification will take place when IUserRepository instance will be release.

If you want to follow the "test spy" pattern (i.e. no expectation defined a priori, but manual check after the execution), you can use:

procedure TMyTest.ForgotMyPassword;
var SmsSender: ISmsSender;
    UserRepository: IUserRepository;
    Spy: TInterfaceMockSpy;
begin
  TInterfaceStub.Create(TypeInfo(ISmsSender),SmsSender).
    Returns('Send',[true]);
  Spy := TInterfaceMockSpy.Create(TypeInfo(IUserRepository),UserRepository,self);
  with TLoginController.Create(UserRepository,SmsSender) do
  try
    ForgotMyPassword('toto');
  finally
    Free;
  end;
  Spy.Verify('Save');
end;

This is something unique with our library: you can decide if you want to use the classic "expect-run-verify" pattern, or the somewhat more direct "run-verify" / "test spy" pattern.
With mORMot, you pick up your mocking class (either TInterfaceMock or TInterfaceMockSpy), then use it as intended. You can even mix the two aspects in the same instance! It is just a matter of taste and opportunity for you to use the right pattern.

If you discovered the mORMot framework, you may have found out that its implementation may sound restricted, in comparison to other ORMs, due to its design. It would be easy to answer that "it is not a bug, it is a feature", but I suspect it is worth a dedicated article.

Some common (and founded) criticisms are the following (quoting from our forum - see e.g. this question):
- "One of the things I don't like so much about your approach to the ORM is the mis-use of existing Delphi constructs like "index n" attribute for the maximum length of a string-property. Other ORMs solve this i.e. with official Class-attributes";
- "You have to inherit from TSQLRecord, and can't persist any plain class";
- "There is no way to easily map an existing complex database".

I understand very well those concerns.
Our mORMot framework is not meant to fit any purpose, but it is worth understanding why it has been implemented as such, and why it may be quite unique within the family of ORMs - which almost all are following the Hibernate way of doing.

In a Stack Overflow question, someone asked about some nested procedure call he found out. That is, a procedure inside another procedure.

He found out this coding style to be messy, which sounds like a reasonable opinion. But his alternative proposal of putting the internal procedure outside the main one, i.e. making it global, is IMHO even worse.

In some case, a private class, or even record or object with methods is an handy and maintainable implementation pattern.

In a discussion with Henrick Hellström, in Embarcadero forums, I wrote some high-level information about mORMot.

It was clear to me that our little mORMot is now far away from a simple Client-Server solution.

The Henrick point was that with Real Thin Client (RTC), you are able to write any Client-Server solution, even a RESTful / JSON based one.

He is of course right, but it made clear to me all the work done in mORMot since its beginning.
From a Client-Server ORM, it is now a complete SOA framework, ready to serve Domain-Driven-Design solutions.

A variety of programming languages suffer from a denial-of-service (DoS) condition against storage functions of key/value pairs in hash data structures, the condition can be leveraged by exploiting predictable collisions in the underlying hashing algorithms.

The issue finds particular exposure in web server applications and/or frameworks. In particular, the lack of sufficient limits for the number of parameters in POST requests in conjunction with the predictable collision properties in the hashing functions of the underlying languages can render web applications vulnerable to the DoS condition. The attacker, using specially crafted HTTP requests, can lead to a 100% of CPU usage which can last up to several hours depending on the targeted application and server performance, the amplification effect is considerable and requires little bandwidth and time on the attacker side.

Source: #2011-003 multiple implementations denial-of-service via hash algorithm collision

Among all trolling subject in forums, you'll find out the great Garbage Collection theme.

Fashion languages rely on it. At the core of the .Net and Java framework, and all scripting languages (like JavaScript, Perl, Python or Ruby), you'll find a Garbage Collector. New developers, just released from schools, do learn about handling memory only in theory, and just can't understand how is memory allocated - we all have seen such rookies involved in Delphi code maintenance, leaking memory as much as they type. In fact, most of them did not understood how a computer works. I warned you this will be a trolling subject.

And, in Delphi, there is no such collector. We handle memory in several ways:

• Creating static variables - e.g. on the stack, inside a class or globally;
• Creating objects with class instances allocated on heap - in at least three ways: with a try..finally Free block, with a TComponent ownership model in the VCL, or by using an interface (which creates an hidden try..finally Free block);
• Creating reference-counted variables, i.e. string, array of, interface or variant kind of variables.

It is a bit complex, but it is also deadly powerful. You have several memory allocation models at hand, which can be very handy if you want to tune your performance and let program scale. Just like manual recycling at home will save the planet. Some programmers will tell you that it's a waste of cell brain, typing and time. Linux kernel gurus would not say so, I'm afraid.

Then came the big Apple company, which presented its new ARC model (introduced in Mac OS X 10.7 Lion) as a huge benefit for Objective-C in comparison with the Garbage Collection model. And let's face it: this ARC just sounds like the Delphi memory model.

Writing working multi-threaded code is not easy - it's even hard, as as a Delphi expert just wrote in his blog.

In fact, the first step into multi-thread application development could be:

"protect your shared variables with locks (aka critical sections), because you are not sure that the data you read/write is the same for all threads".

The CPU per-core cache is just one of the possible issues, which will lead into reading wrong values. Another issue which may lead into race condition is two threads writing to a resource at the same time: it's impossible to know which value will be stored afterward.

There is a well known syndrome around, against ORM.

Do you remember The Vietnam of Computer Science article?

It is worth reading... and commenting.
Sounds a bit outdated by now. Tempus fugit!

According to the n-Tier architecture, data filtering and validation should be implemented in the business logic, not in the User Interface.

If you were used to develop RAD database application using Delphi, you may have to change a bit your habits here. Data filtering and validation should be implemented not in the User Interface, but in pure Delphi code.

Data filtering is a process run on the User entry: for instance, it will trim left or right spaces, make the text uppercase...
Data validating is performed before saving the data to the database: for instance, an email address is checked for consistency, a field value to be unique...

Some try to implement this using an external scripting engine, in a procedure/event mode. Back to the 80th...
In our ORM framework, filtering and validation can be performed by creating some Delphi classes, which may be used on both Server and Client side.