Synopse Open Source

One common problem when handling dates and times, is that time is shown and entered as local, whereas the computer should better use non-geographic information - especially on a Client-Server architecture, where both ends may not be on the same physical region.

A time zone is a region that observes a uniform standard time for legal, commercial, and social purposes.
Time zones tend to follow the boundaries of countries and their subdivisions because it is convenient for areas in close commercial or other communication to keep the same time.
Most of the time zones on land are offset from Coordinated Universal Time (UTC) by a whole number of hours, or minutes.
Even worse, some countries use daylight saving time for part of the year, typically by changing clocks by an hour, twice every year.

The main rule is that any date and time stored should be stored in UTC, or with an explicit Zone identifier (i.e. an explicit offset to the UTC value).
Our framework expects this behavior: every date/time value stored and handled by the ORM, SOA, or any other part of it, is expected to be UTC-encoded.
At presentation layer (e.g. the User Interface), conversion to/from local times should take place, so that the end-user is provided with friendly clock-wall compatible timing.

As you may guess, handling time zones is a complex task, which should be managed by the Operating System itself.
Since this cultural material is constantly involving, it is updated as part of the OS.

In practice, current local time could be converted from UTC from the current system-wide time zone. One of the only parameters you have to set when installing an Operating System is to pickup the keyboard layout... and the current time zone to be used. But in a client-server environment, you may have to manage several time zones on the server side: so you can't rely on this global setting.

One sad - but predictable - news is that there is no common way of encoding time zone information.
Under Windows, the registry contains a list of time zones, and the associated time bias data. Most POSIX systems (including Linux and Mac OSX) do rely on the IANA database, also called tzdata - you may have noticed that this particular package is often updated with your system.
Both zone identifiers do not map, so our framework needed something to be shared on all systems.

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  […]

We introduced DDD concepts some time ago, in a series of articles in this blog. At that time, we proposed a simple way of using mORMot types to implement DDD in your applications. But all Domain Entitities being tied to the framework TSQLRecord class did appear as a limitation, breaking the  […]

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.