Tag - GoodPractice

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2024-02-01

IDocList/IDocDict JSON for Delphi and FPC

Since years, our Open Source mORMot framework offers several ways to work with any combination of arrays/objects documents defined at runtime, e.g. via JSON, with a lot of features, and very high performance.

Our TDocVariant custom variant type is a powerful way of working with such schema-less data, but it was found confusing by some users.
So we developed a new set of interface definitions around it, to ease its usage, without sacrificing its power. We modelized them around Python Lists and Dictionaries, which is proven ground - with some extensions of course.

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2023-12-09

Native X.509, RSA and HSM Support

Today, almost all computer security relies on asymmetric cryptography and X.509 certificates as file or hardware modules.
And the RSA algorithm is still used to sign the vast majority of those certificates. Even if there are better options (like ECC-256), RSA-2048 seems the actual standard, at least still allowed for a few years.

So we added pure pascal RSA cryptography and X.509 certificates support in mORMot.
Last but not least, we also added Hardware Security Modules support via the PKCS#11 standard.
Until now, we were mostly relying on OpenSSL, but a native embedded solution would be smaller in code size, better for reducing dependencies, and easier to work with (especially for HSM). The main idea is to offer only safe algorithms and methods, so that you can write reliable software, even if you are no cryptographic expert. :)

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2023-10-31

Pascal In The Race: TFB Challenge Benchmarks

Round 22 of the TechEmpower Frameworks has just finished.
And this time, there was a pascal framework in the race: our little mORMot!

Numbers are quite good, because we are rated #12 among 302 frameworks over 791 runs of several configurations.

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2023-09-08

End Of Live OpenSSL 1.1 vs Slow OpenSSL 3.0

mormotSecurity.jpg, Sep 2023

You may have noticed that the OpenSSL 1.1.1 series will reach End of Life (EOL) next Monday...
Most sensible options are to switch to 3.0 or 3.1 as soon as possible.

mormotSecurity.jpg, Sep 2023

Of course, our mORMot 2 OpenSSL unit runs on 1.1 and 3.x branches, and self-adapt at runtime to the various API incompatibilities existing between each branch.
But we also discovered that switching to OpenSSL 3.0 could led into big performance regressions... so which version do you need to use?

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2023-07-20

The LUTI and the mORMot

RegressTests.png, Jul 2023

Since its earliest days, our mORMot framework did offer extensive regression tests. In fact, it is fully test-driven, and almost 78 million individual tests are performed to cover all its abilities:

RegressTests.png, Jul 2023

We just integrated those tests to the TranquilIT build farm, and its great LUTI tool. So we have now continuous integration tests over several versions of Windows, Linux, and even Mac!
LUTI is the best mORMot's friends these days. :)

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2023-04-19

New Command Line Parser in mORMot 2

For most projects, we want to be able to pass some custom values when starting it.
The command line is then used to add this additional information.

We have ParamStr and ParamCount global functions, enough to retrieve the information. You may also use FindCmdLineSwitch for something more easy to work with.
The Lazarus RTL offers some additional methods like hasOption or getOptionValue or checkOptions in its TCustomApplication class. Their are better, but not so easy to use, and not available on Delphi.

We just committed a new command line parser to our Open Source mORMot 2 framework, which works on both Delphi and FPC, follows both Windows and POSIX/Linux conventions, and has much more features (like automated generation of the help message), in an innovative and easy workflow.

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2022-12-28

Efficient Routing for Christmas

This is perhaps the last new feature of mORMot 2 before its first stable release: a very efficient custom URI routing for our HTTP/HTTPS servers.

At ORM and SOA level, there is by-convention routing of the URI, depending on the ORM table, SOA interface and method, and TOrmModel.Root value. Even for our MVC web part, we rely on a /root/ URI prefix, which may not be always needed.
Relying on convention is perfect between mORMot clients and servers, but in some cases, it may be handy to have something smoother, e.g. to publish a truly REST scheme.

We introduced two routing abilities to mORMot 2, with amazing performance (6-12 million parsings per CPU core), via a new THttpServerGeneric.Route property:

  • Internal URI rewrite, to redirect internally from a human/REST-friendly request e.g. to a SOA /root/interface.method layout, or to a MVC web page;
  • Direct callback execution, with optional parameter parsing.

Article edited on 28th December:
Fixed performance numbers (much higher than reported), and introduced latest source changes.

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2022-11-26

Modern Pascal is Still in the Race

A recent poll on the Lazarus/FPC forum highlighted a fact: pascal coders are older than most coders. Usually, at our age, we should be managers, not developers. But we like coding in pascal. It is still fun after decades!
But does it mean that you should not use pascal for any new project? Are the language/compilers/libraries outdated?
In the company I currently work for, we have young coders, just out-of-school or still-in-school, which joined the team and write great code!

And a recent thread in this very same forum was about comparing languages to implement a REST server, in C#, Go, Scala, TypeScript, Elixir and Rust.
Several pascal versions are about to be contributed, one in which mORMot shines.

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2021-12-19

mORMot 2 Generics and Collections

Generics are a clever way of writing some code once, then reuse it for several types.
They are like templates, or compiler-time shortcuts for type definitions.

In the last weeks, we added a new mormot.core.collections.pas unit, which features:

  • JSON-aware IList<> List Storage;
  • JSON-aware IKeyValue<> Dictionary Storage.

In respect to Delphi or FPC RTL generics.collections, this unit uses interfaces as variable holders, and leverage them to reduce the generated code as much as possible, as the Spring4D 2.0 framework does, but for both Delphi and FPC. It publishes TDynArray and TSynDictionary high-level features like indexing, sorting, JSON/binary serialization or thread safety as Generics strong typing.

Resulting performance is great, especially for its enumerators, and your resulting executable size won't blow up as with the regular RTL unit.

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2020-03-03

Preparing Revision 2.x of the mORMot Framework

The more I think of it, the more I am convinced it is time to change how the framework is versioned.
We have version 1.18 since years... difficult to follow... time to upgrade!


I would like to upgrade mORMot to version 2 - with a major refactoring.

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2019-10-30

EKON 23 Presentation Slides and Code

I just finished my workshop at EKON 23.
Like every year, it was a great event to attempt to, and I enjoyed presenting 2 sessions and 1 workshop.

Sessions were about "Kingdom Driven Design" (KDD), which is the name I used to define a cut-down version of "Domain Driven Design" (DDD).
Less paranoid, a bit less isolation, but perhaps more common sense for the less sensitive projects.
Some presentations and code are now available!

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2019-09-18

Introducing Kingdom Driven Design at EKON 23

There are still some days to join EKON 23 conferences with the reduced price!

I will make 2 sessions, and 1 workshop, in English (my German is not good enough), about practical project design and mORMot.
If you find DDD is a bit too much for you, but still want to write clean code, check this!

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2018-11-12

EKON 22 Slides and Code

I've uploaded two sets of slides from my presentations at EKON 22 : Object Pascal Clean Code Guidelines Proposal High Performance Object Pascal Code on Servers with the associated source code The WorkShop about "Getting REST with mORMot" has a corresponding new Samples folder in our  […]

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2016-10-18

Cheat Mode for Private Keys

In order to follow best practice, our .private key files are always protected by a password.  A random value with enough length and entropy is always proposed by the ECC tool when a key pair is generated, and could be used directly.
It is always preferred to trust a computer to create true randomness (and SynCrypto.pas's secure TAESPRNG was designed to be the best possible seed, using hardware entropy if available), than using our human brain, which could be defeated by dictionary-based password attacks.
Brute force cracking would be almost impossible, since PBKDF2_HMAC_SHA256 Password-Based Key Derivation Function with 60,000 rounds is used, so rainbow tables (i.e. pre-computed passwords list) will be inoperative, and each password trial would take more time than with a regular Key Derivation Function.

The issue with strong passwords is that they are difficult to remember. If you use not pure random passwords, but some easier to remember values with good entropy, you may try some tools like https://xkpasswd.net/s which returns values like $$19*wrong*DRIVE*read*61$$.
But even then, you will be able to remember only a dozen of such passwords. In a typical public key infrastructure, you may create hundredths of keys, so remembering all passwords is no option for an average human being as (you and) me.

At the end, you end up with using a tool to store all your passwords (last trend is to use an online service with browser integration), or - admit it - store them in an Excel document protected by a password. Most IT people - and even security specialists - end with using such a mean of storage, just because they need it.
The weaknesses of such solutions can be listed:

  • How could we trust closed source software and third-party online services?
  • Even open source like http://keepass.info/help/base/security.html may appear weak (no PBKDF, no AFSplit, managed C#, SHA as PRNG);
  • The storage is as safe as the "master password" is safe;
  • If the "master password" is compromised, all your passwords are published;
  • You need to know the master password to add a new item to the store.

The ECC tool is able to work in "cheat mode", storing all .private key files generated passwords in an associated .cheat local file, encrypted using a cheat.public key.

As a result:

  • Each key pair will have its own associated .cheat file, so you only unleash one key at a time;
  • The .cheat file content is meaningless without the cheat.private key and its master password, so you can manage and store them together with your .private files;
  • Only the cheat.public key is needed when creating a key pair, so you won't leak your master password, and even could generate keys in an automated way, on a distant server;
  • The cheat.private key will be safely stored in a separated place, only needed when you need to recover a password;
  • It uses strong File Encryption, with proven PBKDF, AFSplit, AES-PRNG, and ECDH/ECIES algorithms.

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2016-01-09

Safe locks for multi-thread applications

Once your application is multi-threaded, concurrent data access should be protected. We already wrote about how debugging multi-thread applications may be hard.
Otherwise, a "race condition" issue may appear: for instance, if two threads modify a variable at the same time (e.g. decrease a counter), values may become incoherent and unsafe to use. Another symptom of broken logic is the "deadlock", by which the whole application appears to be blocked and unresponsive, when two threads have a wrong use of the lock, so are blocking each-others.
On a server system, which is expected to run 24/7 with no maintenance, such issues are to be avoided.

In Delphi, protection of a resource (which may be an object, or any variable) is usually done via Critical Sections.
A critical section is an object used to make sure, that some part of the code is executed only by one thread at a time. A critical section needs to be created/initialized before it can be used and be released when it is not needed anymore. Then, some code is protected using Enter/Leave methods, which would lock its execution: in practice, only a single thread would own the critical section, so only a single thread would be able to execute this code section, and other threads would wait until the lock is released. For best performance, the protected sections should be as small as possible - otherwise the benefit of using threads may be voided, since any other thread would wait for the thread owning the critical section to release the lock.

We will now see that Delphi's TCriticalSection may have potential issues, and what our framework proposes to ease critical section use in your applications.

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2015-12-11

Audit Trail for Services

We have seen previously how the ORM part of the framework is able to provide an Audit Trail for change tracking.
It is a very convenient way of storing the change of state of the data.

On the other side, in any modern SOA solution, data is not at the center any more, but services.
Sometimes, the data is not stored within your server, but in a third-party Service-Oriented Architecture (SOA).
Being able to monitor the service execution of the whole system becomes sooner or later mandatory.

Our framework allows to create an Audit Trail of any incoming or outgoing service operation, in a secure, efficient and automated way.

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2015-11-21

Try to avoid RTTI (ab)use

There is a very trendy move, since a few years, to value so called "meta-programming".
In short, it is about the ability to treat programs as their data.
It is a very powerful paradigm in functional languages, and it was also introduced to OOP languages, even in SmallTalk a long time before this concept was trendy in Ruby, C# or Java.

In OOP compiled languages, reflection is used to achieve a similar behavior at run-time, mainly via RTTI (Run-Time Type Information).
Delphi supports RTTI since its version 1, as it was heavily used e.g. for all UI streaming.
In our framework, we rely on RTTI for its main features: ORMSOA and MVC - and even in some other parts, like Desktop UI generation.

But RTTI could easily be abused.
Here are some thoughts, started as a comment in a good old Mason's blog article about how RTTI performance may be a bottleneck.
My comment was to get rid of RTTI, and follow a SOLID implementation with explicit OOP code, like use of interface.

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2015-06-01

Updated Slides about ORM SOA MVC SOLID DDD

One year ago, we published a set of slides about the main concepts implemented by our framework. Mainly about ORM (and ODM), NoSQL, JSON, SOA, MVC (and MVVM), SOLID, DDD, CQRS and some patterns like Stubs, Mocks, Factory, Repository, Unit-Of-Work. Worth a look, if you want to find out the benefits  […]

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2015-05-08

I do not like people shoot in my foot, do you?

There was some discussion about the new TStringHelper feature introduced in latest versions of Delphi.
I was told to be some kind of archaic guy, not able to see the benefit of this.
Reducing opinions to a conservative/progressive approach - another famous 10 kinds of coders - is very reductive.

Of course, this was IMHO unfair and my point was that I have the feeling that some decisions about the Delphi language and RTL are inadequate.
Some changes are welcome. I enjoy the introduction of generics - even if it is was painful, and even buggy (do not use TList<T> with managed record types in XE8!).
But some upcoming changes about the string policy - breaking everything just because we want to align with mainstream C# or Java habits - are just non sense to me.
I really think that Embarcadero deciders like to shoot their own foot.
Or - certainly worse - our own feet!

I will post here some part of the discussion...
So that we may be able to share our ideas.

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2015-05-03

SOLID Design Principles

Single-to-rule-them-all class

I've just updated the documentation part about the SOLID Design Principles.
The former blog article (almost 4 years old!) sounds like a bit deprecated now...
This is why I would extract here an updated version of this material.

Ensure you checked the corresponding part of the mORMot documentation, which is the updated reference, and probably the easiest to read - including links to all the other documentation.

The acronym SOLID is derived from the following OOP principles (quoted from the corresponding Wikipedia article):

  • Single responsibility principle: the notion that an object should have only a single responsibility;
  • Open/closed principle: the notion that "software entities ... should be open for extension, but closed for modification";
  • Liskov substitution principle: the notion that "objects in a program should be replaceable with instances of their subtypes without altering the correctness of that program” - also named as "design by contract";
  • Interface segregation principle: the notion that "many client specific interfaces are better than one general purpose interface.";
  • Dependency inversion principle: the notion that one should "Depend upon Abstractions. Do not depend upon concretions.". Dependency injection is one method of following this principle, which is also called Inversion Of Control (aka IoC).

If you have some programming skills, those principles are general statements you may already found out by yourself. If you start doing serious object-oriented coding, those principles are best-practice guidelines you would gain following.

They certainly help to fight the three main code weaknesses:

  • Rigidity: Hard to change something because every change affects too many other parts of the system;
  • Fragility: When you make a change, unexpected parts of the system break;
  • Immobility: Hard to reuse in another application because it cannot be disentangled from the current application.

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