Tag - Delphi

Entries feed - Comments feed

2016-09-06

Ride the mORMot at EKON 20 in Dusseldorf!

There are still a few days for "very early birds" offer for EKON 20 conference, and meet us for 3 sessions (including a half-day training/introduction to mORMot)! Join us the 7-9th of November in Düsseldorf! Our sessions are not restricted to mORMot, but will use mORMot to illustrate some  […]

Continue reading

2016-05-14

Anti-forensic, safe storage of private keys

In any modern application, especially on Client/Server nTier architecture as our little mORMot offers, we often have to persist some private keys in a safe way.
Problem with such keys is that they consist in small amount of bytes (typically 16 or 32 bytes), easy to be left somewhere in disk or memory.
Given the abilities of recent forensic data recovery methods, data can't be destroyed on magnetic or flash storage media reliably.

We have just added to our SynCrypto OpenSource library the Anti-forensic Information Splitter algorithm, as proposed in TKS1, and implemented in the LUKS standard.
LUKS is the de-facto standard of platform-independent standard on-disk format for use in various tools.

Continue reading

2016-04-22

Support of Delphi 10.1 Berlin

You should have noticed that Delphi 10.1 Berlin has been released. Our Open Source projects, including mORMot and SynPDF and their associated documentation have been updated to support this new revision. Any additional feedback is welcome, as usual!

2016-04-09

AES-256 based Cryptographically Secure Pseudo-Random Number Generator (CSPRNG)

Everyone knows about the pascal random() function.
It returns some numbers, using a linear congruential generator, with a multiplier of 134775813, in its Delphi implementation.
It is fast, but not really secure. Output is very predictable, especially if you forgot to execute the RandSeed() procedure.

In real world scenarios, safety always requires random numbers, e.g. for key/nonce/IV/salt/challenge generation.
The less predictable, the better.
We just included a Cryptographically Secure Pseudo-Random Number Generator (CSPRNG) into our SynCrypto.pas unit.
The TAESPRNG class would use real system entropy to generate a sequence of pseudorandom bytes, using AES-256, so returning highly unpredictable content.

Continue reading

2016-02-08

Linux support for Delphi to be available end of 2016

Marco Cantu, product manager of Delphi/RAD Studio, did publish the official RAD Studio 2016 Product Approach and Roadmap.
The upcoming release has a codename known as "BigBen", and should be called Delphi 10.1 Berlin, as far as I understand.

After this summer, another release, which codename is "Godzilla", will support Linux as a compiler target, in its Delphi 10.2 Tokyo release.
This is a very good news, and some details are given.
I've included those official names to mORMot's internal compiler version detection.
Thanks Marco for the information, and pushing in this direction!

My only concern is that it would be "ARC-enabled"...

Continue reading

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.

Continue reading

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.

Continue reading

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.

Continue reading

2015-11-17

Benefits of interface callbacks instead of class messages

If you compare with existing client/server SOA solutions (in Delphi, Java, C# or even in Go or other frameworks), mORMot's interface-based callback mechanism sounds pretty unique and easy to work with.

Most Events Oriented solutions do use a set of dedicated messages to propagate the events, with a centralized Message Bus (like MSMQ or JMS), or a P2P/decentralized approach (see e.g. ZeroMQ or NanoMsg). In practice, you are expected to define one class per message, the class fields being the message values. You would define e.g. one class to notify a successful process, and another class to notify an error. SOA services would eventually tend to be defined by a huge number of individual classes, with the temptation of re-using existing classes in several contexts.

Our interface-based approach allows to gather all events:

  • In a single interface type per notification, i.e. probably per service operation;
  • With one method per event;
  • Using method parameters defining the event values.

Since asynchronous notifications are needed most of the time, method parameters would be one-way, i.e. defined only as const - in such case, an evolved algorithm would transparently gather those outgoing messages, to enhance scalability when processing such asynchronous events. Blocking request may also be defined as var/out, as we will see below, inWorkflow adaptation.

Behind the scene, the framework would still transmit raw messages over IP sockets (currently over a WebSockets connection), like other systems, but events notification would benefit from using interfaces, on both server and client sides.
We will now see how...

Continue reading

2015-10-23

Letters of Hope

As we already notified in this blog, Embarcadero has been finally bought by IDERA. Delphi users received a letter from Randy Jacops, IDERA CEO. Written in my mother language, in perfect French. Nice! The letter states that they have 20,000 customers... It sounds more realistic than the numbers  […]

Continue reading

2015-10-05

Delphi 10 Seattle Win64 compiler Heisenbug: unusable target

Andy reported that he was not able to validate its IDE fix pack for Delphi 10 Seattle, due to its Win64 compiler not being deterministic anymore. The generated code did vary, from one build to other. Sadly, on our side, we identified that the code generated by the Win64 compiler of Delphi 10 Seattle  […]

Continue reading

2015-09-28

mORMot show case: Illustrated Spare Parts Catalog

Illustrated Spare Parts Catalog is, as its name suggests, a software for creating and publishing spare parts catalogs. It uses mORMot for client-server communication and ORM, and SynPdf for the reporting. Sounds like a powerful solution. It is also a testimony that you could use big databases (20 GB  […]

Continue reading

2015-09-25

ORM TNullable* fields for NULL storage

In Delphi code, NULLable types do not exist as such. There is no native int? type, as in C#.
But at SQL and JSON levels, the NULL value does exist and should be converted as expected by the ORM.

In SQLite3 itself, NULL is handled as stated in http://www.sqlite.org/lang_expr.html (see e.g. IS and IS NOT operators).
It is worth noting that NULL handling is not consistent among all existing database engines, e.g. when you are comparing NULL with non NULL values... so we recommend using it with care in any database statements, or only with proper (unit) testing, when you switch from one database engine to another.

By default, in the mORMot ORM/SQL code, NULL will appear only in case of a BLOB storage with a size of 0 bytes.
Otherwise, you should not see it as a value, in most kinds of ORM properties.

Null-oriented value types have been implemented in our framework, since the object pascal language does not allow defining a nullable type (yet)

We choose to store those values as variant, with a set of TNullable dedicated types, as defined in mORMot.pas:

type
  TNullableInteger = type variant;
  TNullableBoolean = type variant;
  TNullableFloat = type variant;
  TNullableCurrency = type variant;
  TNullableDateTime = type variant;
  TNullableTimeLog = type variant;
  TNullableUTF8Text = type variant;

Continue reading

2015-09-21

Embarcadero bought by Idera

Just a link found on Internet. Jefferies is also leading a US$425m covenant-lite credit to back Idera's acquisition of Embarcadero Technologies. Idera is backed by TA Associates. The deal, which launches on Thursday, includes a US$25m revolving credit, a US$300m first-lien term loan and a US$100m  […]

Continue reading

2015-09-17

AVAST did detect ALL Delphi programs as dangerous

Today, an avalanche of "false postitive detection" of AVAST heuristic engine did occur.
Any executable built with Delphi XE8 or Delphi 10 Seattle was identified as a Win32:Banker-MGC [Trj] threat!

Heuristic analysis is a method employed by many computer antivirus programs designed to detect previously unknown computer viruses, as well as new variants of viruses already in the "wild".

Continue reading

2015-09-16

Feedback from the Wild

We just noticed a nice feedback from a mORMot user. Vojko Cendak commented the well-known DataSnap analysis based on Speed & Stability tests blog article written by Roberto some months years (!) ago. It is not meant to be the final word, perhaps there was some tuning possible for RTC (which is  […]

Continue reading

2015-09-14

Performance issue in NextGen ARC model - much better now

Back in 2013, I found out an implementation weakness in the implementation of ARC weak references in the RTL.
A giant lock was freezing all threads and cores, so would decrease a lot the performance abilities of any ARC application, especially in multi thread.

I just investigated that things are now better.

Continue reading

2015-08-31

Delphi 10 = DX Seattle is out, mORMot supports it

We expected Delphi XE9, and now we have Rad Studio 10 Seattle, with Delphi renamed as Delphi 10 Seattle, or simply DX. No big news for the Delphi compiler itself (we are still waiting for Linux server support), but a lot of FireMonkey updates, Windows 10 compatibility enhancements, enhancements to  […]

Continue reading

2015-08-24

Introducing Delphinus PackageManager

You may have missed the news. So I relay here the information from Delphinus PackageManager blog article. Delphinus is a new Package Manager, which runs on Delphi XE and newer, directly from within your IDE. It is GitHub-based, and fairly easy to add a reference to. Of course, I tried to add mORMot  […]

Continue reading

2015-08-23

"SQL and NoSQL", not "SQL vs NoSQL"

You know certainly that our mORMot Open Source framework is an ORM, i.e. mapping objects to a relational / SQL database (Object Relational Mapping).
You may have followed also that it is able to connect to a NoSQL database, like MongoDB, and that the objects are then mapped via an ODM (Object Document Mapping) - the original SQL SELECT are even translated on the fly to MongoDB queries.

But thanks to mORMot, it is not "SQL vs NoSQL" - but "SQL and NoSQL".
You are not required to make an exclusive choice.
You can share best of both worlds, depending on your application needs.

In fact, the framework is able to add NoSQL features to a regular relational / SQL database, by storing JSON documents in TEXT columns.

In your end-user code, you just define a variant field in the ORM, and store a TDocVariant document within.
We also added some dedicated functions at SQL level, so that SQLite3 could be used as embedded fast engine, and provide advanced WHERE clauses on this JSON content.

Continue reading

- page 2 of 17 -