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2014, Friday April 18

Introducing mORMot's architecture and design principles

We have just released a set of slides introducing 

  • ORM, SOA, REST, JSON, MVC, MVVM, SOLID, Mocks/Stubs, Domain-Driven Design concepts with Delphi, 
  • and showing some sample code using our Open Source mORMot framework.

You can follow the public link on Google Drive!

This is a great opportunity to discovers some patterns you may not be familiar with, and find out how mORMot try to implement them.
This set of slides may be less intimidating than our huge documentation - do not be terrified by our 1400 pages Software Architecture Design pdf!

Feedback is welcome on our forum, as usual.

2014, Monday April 7

JavaScript support in mORMot via SpiderMonkey

As we already stated, we finished the first step of integration of the SpiderMonkey engine to our mORMot framework.
Version 1.8.5 of the library is already integrated, and latest official revision will be soon merged, thanks to mpv's great contribution.
It can be seen as stable, since it is already used on production site to serve more than 1,000,000 requests per day.

You can now easily uses JavaScript on both client and server side.
On server side, mORMot's implementation offers an unique concept, i.e. true multi-threading, which is IMHO a huge enhancement when compared to the regular node.js mono-threaded implementation, and its callback hell.
In fact, node.js official marketing states its non-blocking scheme is a plus. It allows to define a HTTP server in a few lines, but huge server applications need JavaScript experts not to sink into a state a disgrace.

Continue reading...

2014, Tuesday February 25

TDocVariant custom variant type

With revision 1.18 of the framework, we just introduced two new custom types of variants:

  • TDocVariant kind of variant;
  • TBSONVariant kind of variant.

The second custom type (which handles MongoDB-specific extensions - like ObjectID or other specific types like dates or binary) will be presented later, when dealing with MongoDB support in mORMot, together with the BSON kind of content. BSON / MongoDB support is implemented in the SynMongoDB.pas unit.

We will now focus on TDocVariant itself, which is a generic container of JSON-like objects or arrays.
This custom variant type is implemented in SynCommons.pas unit, so is ready to be used everywhere in your code, even without any link to the mORMot ORM kernel, or MongoDB.

TDocVariant documents

TDocVariant implements a custom variant type which can be used to store any JSON/BSON document-based content, i.e. either:

  • Name/value pairs, for object-oriented documents;
  • An array of values (including nested documents), for array-oriented documents;
  • Any combination of the two, by nesting TDocVariant instances.

Here are the main features of this custom variant type:

  • DOM approach of any object or array documents;
  • Perfect storage for dynamic value-objects content, with a schema-less approach (as you may be used to in scripting languages like Python or JavaScript);
  • Allow nested documents, with no depth limitation but the available memory;
  • Assignment can be either per-value (default, safest but slower when containing a lot of nested data), or per-reference (immediate reference-counted assignment);
  • Very fast JSON serialization / un-serialization with support of MongoDB-like extended syntax;
  • Access to properties in code, via late-binding (including almost no speed penalty due to our VCL hack as already detailed);
  • Direct access to the internal variant names and values arrays from code, by trans-typing into a TDocVariantData record;
  • Instance life-time is managed by the compiler (like any other variant type), without the need to use interfaces or explicit try..finally blocks;
  • Optimized to use as little memory and CPU resource as possible (in contrast to most other libraries, it does not allocate one class instance per node, but rely on pre-allocated arrays);
  • Opened to extension of any content storage - for instance, it will perfectly integrate with BSON serialization and custom MongoDB types (ObjectID, RegEx...), to be used in conjunction with MongoDB servers;
  • Perfectly integrated with our Dynamic array wrapper and its JSON serialization as with the record serialization;
  • Designed to work with our mORMot ORM: any TSQLRecord instance containing such variant custom types as published properties will be recognized by the ORM core, and work as expected with any database back-end (storing the content as JSON in a TEXT column);
  • Designed to work with our mORMot SOA: any interface-based service is able to consume or publish such kind of content, as variant kind of parameters;
  • Fully integrated with the Delphi IDE: any variant instance will be displayed as JSON in the IDE debugger, making it very convenient to work with.

To create instances of such variant, you can use some easy-to-remember functions:

  • _Obj() _ObjFast() global functions to create a variant object document;
  • _Arr() _ArrFast() global functions to create a variant array document;
  • _Json() _JsonFast() _JsonFmt() _JsonFastFmt() global functions to create any variant object or array document from JSON, supplied either with standard or MongoDB-extended syntax.

Continue reading...

2014, Friday January 10

RESTful mORMot

Our Synopse mORMot Framework was designed in accordance with Fielding's REST architectural style without using HTTP and without interacting with the World Wide Web.
Such Systems which follow REST principles are often referred to as "RESTful".

Optionally, the Framework is able to serve standard HTTP/1.1 pages over the Internet (by using the mORMotHttpClient / mORMotHttpServer units and the TSQLHttpServer and TSQLHttpClient classes), in an embedded low resource and fast HTTP server.

Continue reading...

REpresentational State Transfer (REST)

Representational state transfer (REST) is a style of software architecture for distributed hypermedia systems such as the World Wide Web.
As such, it is not just a method for building "web services". The terms "representational state transfer" and "REST" were introduced in 2000 in the doctoral dissertation of Roy Fielding, one of the principal authors of the Hypertext Transfer Protocol (HTTP) specification, on which the whole Internet rely.

 

There are 5 basic fundamentals of web which are leveraged to create REST services:

  1. Everything is a Resource;
  2. Every Resource is Identified by a Unique Identifier;
  3. Use Simple and Uniform Interfaces;
  4. Communication is Done by Representation;
  5. Every Request is Stateless.

Continue reading...

2013, Tuesday December 10

JSON record serialization

In Delphi, the record has some nice advantages:

  • record are value objects, i.e. accessed by value, not by reference - this can be very convenient, e.g. when defining a Domain-Driven Design
  • record can contain any other record or dynamic array, so are very convenient to work with (no need to define sub-classes or lists); 
  • record variables can be allocated on stack, so won't solicit the global heap; 
  • record instances automatically freed by the compiler when they come out of scope, so you won't need to write any try..finally Free; end block.

Serialization of record values are therefore a must-have for a framework like mORMot.

In recent commits, this JSON serialization of record has been enhanced.
In particular, we introduced JSON serialization via a new text-based record definition.

Continue reading...

2013, Tuesday September 10

Thread-safety of mORMot

We tried to make mORMot at the same time fast and safe, and able to scale with the best possible performance on the hardware it runs on.
Multi-threading is the key to better usage of modern multi-core CPUs, and also client responsiveness.

As a result, on the Server side, our framework was designed to be thread-safe.

On typical production use, the mORMot HTTP server will run on its own optimized thread pool, then call the TSQLRestServer.URI method. This method is therefore expected to be thread-safe, e.g. from the TSQLHttpServer. Request method. Thanks to the RESTful approach of our framework, this method is the only one which is expected to be thread-safe, since it is the single entry point of the whole server. This KISS design ensure better test coverage.

Let us see now how this works, and publish some benchmarks to test how efficient it has been implemented.

Continue reading...

2013, Monday September 2

Summer videos of mORMot

During this summer, warleyalex did meet some mORMots in the mountains of REST, Java, AJAX and JSON.

(picture may differ from actual user:) )

He did some videos of his experiment with our little rodent.
At this time, there are 11 videos available!

Latest one is a Java client application, communicating with a mORMot server and a SQLite3 database.

Please go to this forum post to find all URIs, and put your feedback.

Thanks a lot for sharing!

2013, Sunday June 16

FireDAC / AnyDAC support for mORMot

Our SynDB classes feature now FireDAC / AnyDAC access, with full speed!

Up to now, only UniDAC, BDE or ZEOS components were available as source, but we just added FireDAC / AnyDAC.

FireDAC is an unique set of Universal Data Access Components for developing cross platform database applications on Delphi. This was in fact a third-party component set, bought by Embarcadero to DA-SOFT Technologies (formerly known as AnyDAC), and included with several editions of Delphi XE3 and up. This is the new official platform for high-speed database development in Delphi, in favor to the now deprecated DBExpress.

Our integration within SynDB.pas units and the mORMot persistence layer has been tuned. For instance, you can have direct access to high-speed FireDAC Array DML feature, via the ORM batch process, via so-called array binding.

Continue reading...

2013, Friday June 14

SQLite3 performance in Exclusive file locking mode

As stated in previous blog articles, the default SQlite3 write speed is quite slow, when running on a normal hard drive. By default, the engine will pause after issuing a OS-level write command. This guarantees that the data is written to the disk, and features the ACID properties of the database engine.

ACID is an acronym for "Atomicity Consistency Isolation Durability" properties, which guarantee that database transactions are processed reliably: for instance, in case of a power loss or hardware failure, the data will be saved on disk in a consistent way, with no potential loss of data.

In SQLite3, ACID is implemented by two means at file level:
- Synchronous writing: it means that the engine will wait for any written content to be flushed to disk before processing the next request;
- File locking: it means that the database file is locked for exclusive use during writing, allowing several processes to access the same database file concurrently.

Changing these default settings can ensure much better writing performance.

We just added direct File locking tuning.
It appears that defining exclusive access mode is able to increase the performance a lot, in both reading and writing speed.

Here are some new benchmarks and data, extracted from the updated SAD documentation.

Continue reading...

2013, Wednesday April 24

mORMots know how to swim like fishes

Another great video by warleyalex.

This time, a full FishFacts demo in AJAX, using mORMot and its SQLite3 ORM as server.

See it on YouTube!

Feedback is welcome on our forum.

Update:

I've just uploaded the corresponding source code to our repository.
See sample 19 - AJAX ExtJS FishFacts.
You need to download the corresponding DB file to run the sample.
Enjoy!

2013, Tuesday April 2

Two videos about EXTjs client of mORMot server

Two nice videos, posted by a framework user.

The first one presents a remote RESTful access of a SQLite3 database, hosted by a mORMot server:

After one post in the forum, warleyalex was able to easily add remote filtering of the request:

In addition to the previous video about security (by which the mORMot authentication model seems much more secure than DataSnap's), this is a very nice demo!
Thanks a lot, warleyalex for the feedback and information!

2013, Thursday March 7

64 bit compatibility of mORMot units

I'm happy to announce that mORMot units are now compiling and working great in 64 bit mode, under Windows.
Need a Delphi XE2/XE3 compiler, of course!

ORM and services are now available in Win64, on both client and server sides.
Low-level x64 assembler stubs have been created, tested and optimized.
UI part is also available... that is grid display, reporting (with pdf export and display anti-aliasing), ribbon auto-generation, SynTaskDialog, i18n... the main SynFile demo just works great!

Overall impression is very positive, and speed is comparable to 32 bit version (only 10-15% slower).

Speed decrease seems to be mostly due to doubled pointer size, and some less optimized part of the official Delphi RTL.
But since mORMot core uses its own set of functions (e.g. for JSON serialization, RTTI support or interface calls or stubbing), we were able to release the whole 64 bit power of your hardware.

Delphi 64 bit compiler sounds stable and efficient. Even when working at low level, with assembler stubs.
Generated code sounds more optimized than the one emitted by FreePascalCompiler - and RTL is very close to 32 bit mode.
Overall, VCL conversion worked as easily than a simple re-build.
Embarcadero's people did a great job for VCL Win64 support, here!

Continue reading...

2013, Sunday February 17

Interface-based service sample: remote SQL access

You will find in the SQLite3\Sample\16 - Execute SQL via services folder of mORMot source code a Client-Server sample able to access any external database via JSON and HTTP.
It is a good demonstration of how to use an interface-based service between a client and a server.
It will also show how our SynDB classes have a quite abstract design, and are easy to work with, whatever database provider you need to use.

The corresponding service contract has been defined:

  TRemoteSQLEngine = (rseOleDB, rseODBC, rseOracle, rseSQlite3, rseJet, rseMSSQL);

IRemoteSQL = interface(IInvokable) ['{9A60C8ED-CEB2-4E09-87D4-4A16F496E5FE}'] procedure Connect(aEngine: TRemoteSQLEngine; const aServerName, aDatabaseName, aUserID, aPassWord: RawUTF8); function GetTableNames: TRawUTF8DynArray; function Execute(const aSQL: RawUTF8; aExpectResults, aExpanded: Boolean): RawJSON; end;

Purpose of this service is:
- To Connect() to external databases, given the parameters of a standard TSQLDBConnectionProperties. Create() constructor;
- Retrieve all table names of this external database as a list;
- Execute any SQL statement, returning the content as JSON array, ready to be consumed by AJAX applications (if aExpanded is true), or a Delphi client (e.g. via a TSQLTableJSON and the mORMotUI unit).

Of course, this service will be define as sicClientDriven mode, that is, the framework will be able to manage a client-driven TSQLDBProperties instance life time.

Benefit of this service is that no database connection is required on the client side: a regular HTTP connection is enough.
No need to install nor configure any database provider, and full SQL access to the remote databases.

Due to our optimized JSON serialization, it will probably be faster to work with such plain HTTP / JSON services, instead of a database connection through a VPN. In fact, database connections are made to work on a local network, and do not like high-latency connections, which are typical on the Internet.

Continue reading...

2013, Tuesday February 12

Introducing ZEOS, UniDAC, NexusDB, BDE, any TDataset to SynDB and mORMot's ORM

Up to now, our SynDB database classes were handling ODBC, OleDB providers and direct Oracle or SQLite3 connection.

We have added a DB.pas based layer, ready to be used with UniDAC, NexusDB, or the BDE.
Any other TDataset based component is ready to be interfaced, including UIB, AnyDAC or DBExpress.

The ZEOS library (in its latest 7.0.3 stable version, which works from Delphi 7 up to XE3) has also been interfaced, but without the TDataset/DB.pas layer: our SynDBZEOS.pas unit calls the ZDBC layer, which is not tied to DB.pas nor its RAD components, and is therefore faster. By the way, it will work also with the Starter edition of Delphi (which does not include the DB components) - just like the other "regular" SynDB classes.

This is a work in progress, any testing and feedback is welcome!
We had to circumvent some particularities of the libraries, but I guess we have something interesting.

A dedicated "SynDBDataset" sub-folder has been created in the repository, to contain all SynDBDataset.pas-based database providers.
SynDBNexusDB.pas unit has been moved within this sub-folder, as SynDBUniDAC.pas + SynDBBDE.pas units have been added.
SynDBZeos.pas has a direct access to the ZDBC layer, so is not part of the "SynDBDataset" sub-folder.

Here is some benchmark, mainly about Oracle and SQlite3 database access.
Of course, our direct SynDBOracle / SynDBSQLite3 layers are the fastest around, and we can see that ZDBC layer is sometimes more efficient than the TDataset components.

Continue reading...

2013, Monday January 28

External database speed improvements

Some major speed improvements have been made to our SynDB* units, and how they are used within the mORMot persistence layer.
It results in an amazing speed increase, in some cases.

Here are some of the optimizations how took place in the source code trunk:

Overall, I observed from x2 to x10 performance boost with simple Add() operations, using ODBC, OleDB and direct Oracle access, when compare to previous benchmarks (which were already impressive).
BATCH mode performance is less impacted, since it by-passed some of those limitations, but even in this operation mode, there is some benefits (especially with ODBC and OleDB).

Here are some results, directly generated by the supplied "15 - External DB performance" sample.

Continue reading...

2013, Friday January 18

Register any class for proper TObjectList serialization

Up to now, the only way of directly serializing a list of class instances as a JSON array was to use a TCollection.

In fact, objects are not alone, just like mORMots tend to have a nice family:

You have either to let your collection class inherit from the new TInterfaceCollection type, either call the TJSONSerializer.RegisterCollectionForJSON() method.
Could sounds a bit over-sized for just a list of objects.

We have just added a new feature, adding a new "ClassName":"TMyObject" field in the JSON object serialization, and allowing it to create the proper class instance on both transmission sides, therefore able to properly let TObjectList be serialized and un-serialized.

Continue reading...

Register any TCollection type for proper JSON serialization

Due to the current implementation pattern of the TCollection type in Delphi, it was not possible to implement directly this kind of parameter.

In fact, the TCollection constructor is defined as such:

 constructor Create(ItemClass: TCollectionItemClass);

And, on the server side, we do not know which kind of TCollectionItemClass is to be passed. Therefore, the TServiceFactoryServer is unable to properly instantiate the object instances, supplying the expected item class.

The framework propose two potential solutions:

  • You can let your collection class inherit from the new TInterfaceCollection type;
  • You can call the TJSONSerializer.RegisterCollectionForJSON() method to register the collection type and its associated item class.

First solution has already been detailed in this blog.
We will now describe the second (and new) way.

Continue reading...

2012, Monday December 31

Enhance existing projects with mORMot

Even if mORMot will be more easily used in a project designed from scratch, it fits very well the purpose of evolving any existing Delphi project, or even creating the server side part of an AJAX application. 

One benefit of such a framework is to facilitate the transition from a Client-Server architecture to a N-Tier layered pattern.

Continue reading...

2012, Friday November 30

Transmission between mORMots

Little mORMots have a very efficient transmission protocol, in their mountains...

Most mORMots are highly social and use loud whistles to communicate with one another, especially when alarmed.
As stated by Wikipedia

In a comment of the already quoted blog article about DataSnap performance issues, Tom asked this interesting question about mORMot, after I presented how we like to use http.sys kernel-mode server to achieve best performance possible over HTTP:

What about TCP communication, http is not the only Internet protocol. Protobuf, Thrift, MsgPack, BSON etc, is binary protocol and http i big overhead in some systems.
Did http.sys enable use of tcp/ip socket protocol?

Continue reading...

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