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2014, Monday August 11

Cross-Platform mORMot Clients - Smart Mobile Studio

Current version of the main framework units target only Win32 and Win64 systems.

It allows to make easy self-hosting of mORMot servers for local business applications in any corporation, or pay cheap hosting in the Cloud, since mORMot CPU and RAM expectations are much lower than a regular IIS-WCF-MSSQL-.Net stack.
But in a Service-Oriented Architecture (SOA), you would probably need to create clients for platforms outside the Windows world, especially mobile devices.

A set of cross-platform client units is therefore available in the CrossPlatform sub-folder of the source code repository. It allows writing any client in modern object pascal language, for:

  • Any version of Delphi, on any platform (Mac OSX, or any mobile supported devices);
  • FreePascal Compiler 2.7.1;
  • Smart Mobile Studio 2.1, to create AJAX or mobile applications (via PhoneGap, if needed).

This series of articles will introduce you to mORMot's Cross-Platform abilities:

Any feedback is welcome in our forum, as usual!

Continue reading...

Cross-Platform mORMot Clients - Delphi / FreePascal

Current version of the main framework units target only Win32 and Win64 systems.

It allows to make easy self-hosting of mORMot servers for local business applications in any corporation, or pay cheap hosting in the Cloud, since mORMot CPU and RAM expectations are much lower than a regular IIS-WCF-MSSQL-.Net stack.
But in a Service-Oriented Architecture (SOA), you would probably need to create clients for platforms outside the Windows world, especially mobile devices.

A set of cross-platform client units is therefore available in the CrossPlatform sub-folder of the source code repository. It allows writing any client in modern object pascal language, for:

  • Any version of Delphi, on any platform (Mac OSX, or any mobile supported devices);
  • FreePascal Compiler 2.7.1;
  • Smart Mobile Studio 2.1, to create AJAX or mobile applications (via PhoneGap, if needed).

This series of articles will introduce you to mORMot's Cross-Platform abilities:

Any feedback is welcome in our forum, as usual!

Continue reading...

Cross-Platform mORMot Clients - Generating Code Wrappers

Current version of the main framework units target only Win32 and Win64 systems.

It allows to make easy self-hosting of mORMot servers for local business applications in any corporation, or pay cheap hosting in the Cloud, since mORMot CPU and RAM expectations are much lower than a regular IIS-WCF-MSSQL-.Net stack.
But in a Service-Oriented Architecture (SOA), you would probably need to create clients for platforms outside the Windows world, especially mobile devices.

A set of cross-platform client units is therefore available in the CrossPlatform sub-folder of the source code repository. It allows writing any client in modern object pascal language, for:

  • Any version of Delphi, on any platform (Mac OSX, or any mobile supported devices);
  • FreePascal Compiler 2.7.1;
  • Smart Mobile Studio 2.1, to create AJAX or mobile applications (via PhoneGap, if needed).

This series of articles will introduce you to mORMot's Cross-Platform abilities:

Any feedback is welcome in our forum, as usual!

Continue reading...

Cross-Platform mORMot Clients - Units and Platforms

Current version of the main framework units target only Win32 and Win64 systems.

It allows to make easy self-hosting of mORMot servers for local business applications in any corporation, or pay cheap hosting in the Cloud, since mORMot CPU and RAM expectations are much lower than a regular IIS-WCF-MSSQL-.Net stack.
But in a Service-Oriented Architecture (SOA), you would probably need to create clients for platforms outside the Windows world, especially mobile devices.

A set of cross-platform client units is therefore available in the CrossPlatform sub-folder of the source code repository. It allows writing any client in modern object pascal language, for:

  • Any version of Delphi, on any platform (Mac OSX, or any mobile supported devices);
  • FreePascal Compiler 2.7.1;
  • Smart Mobile Studio 2.1, to create AJAX or mobile applications (via PhoneGap, if needed).

This series of articles will introduce you to mORMot's Cross-Platform abilities:

Any feedback is welcome in our forum, as usual!

Continue reading...

2014, Sunday May 18

Automatic JSON serialization of record or dynamic arrays via Enhanced RTTI

Since Delphi 2010, the compiler generates additional RTTI at compilation, so that all record fields are described, and available at runtime.
By the way, this enhanced RTTI is one of the reasons why executables did grow so much in newer versions of the compiler.

Our SynCommons.pas unit is now able to use this enhanced information, and let any record be serialized via RecordLoad() and RecordSave() functions, and all internal JSON marshalling process.

In short, you have nothing to do.
Just use your record as parameters, and, with Delphi 2010 and up, they will be serialized as valid JSON objects.

Of course, text-based definition or callback-based registration are still at hand, and will be used with older versions of Delphi.
But you could be used to by-pass or extend the enhanced-RTTI serialization, even on newer versions of the compiler.

Continue reading...

New sample for JSON performance: mORMot vs SuperObject/XSuperObject/dwsJSON/DBXJSON

We have just added a new "25 - JSON performance" sample to benchmark JSON process, using well most known Delphi libraries...

A new fight
featuring
mORMot vs SuperObject/XSuperObject/dwsJSON/DBXJSON

On mORMot side, it covers TDocVariant, late binding, TSQLTable, ORM, record access, BSON...

We tried to face several scenarios:

  • parse/access/write iteration over a small JSON document,
  • read of deeply nested 680 KB JSON (here mORMot is slower than SO/dwsJSON),
  • read of one 180 MB JSON file (with on-the-fly adaptation to fit a record layout),
  • named access to all rows and columns of a 1 MB JSON table, extracted from a SQL request (with comparison with our ORM performance).

On average and in details, mORMot is the fastest in almost all scenarios (with an amazing performance for table/ORM processing), dwsJSON performs very well (better than SuperObject), and DBXJSON is the slowest (by far, but XE6 version is faster than XE4).

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...

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, Wednesday October 9

Good old object is not to be deprecated - it is the future

Yes, I know this article title is a huge moment of trolling for most Delphi developer.
But object could be legend... - wait for it - ... dary!

You perhaps already noticed by several blog posts here that I still like the good old (and deprecated) object type, in addition to the common heap-allocated class type.
Plain record with methods does not match the object-oriented approach of object, since it does not feature inheritance.

When you take a look at modern strongly-typed languages, targeting concurrent programming (you know, multi-thread/multi-core execution), you will see that the objects may be allocated in several ways, to facilitate execution flow.

The Rust language for instance is pretty interesting. It has optional task-local Garbage Collection and safe pointer types with region analysis.

To some extent, it is very similar to what object allows in the Delphi world, and why I'm still using/loving it!

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, Thursday May 3

Custom JSON serialization of records

By default, during interface-based service call, any record parameter or function result will be serialized with our proprietary binary (and optimized layout) - i.e. RecordLoad and RecordSave functions - then encoded in Base-64, to be stored as plain text within the JSON stream.

But custom record JSON serialization can be defined, as with any class - see this article - or dynamic array - see this article.

Continue reading...

2012, Thursday April 12

Custom JSON serialization of any dynamic array content

One nice feature of the TDynArray wrapper and its associated methods, as defined and used in our framework, is the ability to serialize any dynamic array as JSON content.

By default, only "standard" dynamic arrays (like TIntegerDynArray) are serialized as true JSON array: other not known kind of arrays are serialized as binary content, within a Base64 encoding.

This is a very efficient solution for a pure Delphi application, since it will be fast and always works, but won't be easy to deal with from an AJAX client.

Applications can now supply a custom JSON serialization for any other dynamic array, via the TTextWriter.RegisterCustomJSONSerializer() class method.
Two callbacks are to be supplied for a dynamic array type information, in order to handle proper serialization and un-serialization of the JSON array.

Continue reading...

2012, Tuesday April 10

How function results are allocated

One potential issue with Delphi coding, is about how the result of a functions are implemented.

If you forget to set a result value to a function, you'll get a compiler warning.
Never underestimate such warning: IMHO this is not a warning, but an error.

And you should better be aware of the handling of reference-counted types (e.g. string) in a function results: those are passed the stack as var parameters, so the result of a function may be set even if an exception is raised during function execution!

Continue reading...

2011, Thursday December 8

Avoiding Garbage Collector: Delphi and Apple side by side

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.

Continue reading...

2011, Tuesday May 24

How to implement RESTful authentication

How to handle authentication in a RESTful Client-Server architecture is a matter of debate.

Commonly, it can be achieved, in the SOA over HTTP world via:
- HTTP basic auth over HTTPS;
- Cookies and session management;
- Query Authentication with additional signature parameters.

We'll have to adapt, or even better mix those techniques, to match our framework architecture at best.

Each authentication scheme has its own PROs and CONs, depending on the purpose of your security policy and software architecture.

Continue reading...

2011, Friday May 20

How to write fast multi-thread Delphi applications

How to make your software run fast, especially in a multi-threaded architecture?

We tried to remove the Memory Manager scaling problems in our SynScaleMM. It worked as expected in a multi-threaded server environment. Scaling is much better than FastMM4, for some critical tests. But it's not ready for production yet...

To be honest, the Memory Manager is perhaps not the bigger bottleneck in Multi-Threaded applications.

Here are some (not dogmatic, just from experiment and knowledge of low-level Delphi RTL) advice if you want to write FAST multi-threaded application in Delphi.

Continue reading...

2011, Saturday May 14

Virtual Tables in the SQLite3 framework

The SQlite3 engine has ability to create Virtual Tables from code. From the perspective of an SQL statement, the virtual table object looks like any other table or view. But behind the scenes, queries from and updates to a virtual table invoke callback methods on the virtual table object instead of reading and writing to the database file.

The virtual table mechanism allows an application to publish interfaces that are accessible from SQL statements as if they were tables. SQL statements can in general do anything to a virtual table that they can do to a real table, with the following exceptions:
- One cannot create a trigger on a virtual table.
- One cannot create additional indices on a virtual table. (Virtual tables can have indices but that must be built into the virtual table implementation. Indices cannot be added separately using CREATE INDEX statements.)
- One cannot run ALTER TABLE ... ADD COLUMN commands against a virtual table.
- Particular virtual table implementations might impose additional constraints. For example, some virtual implementations might provide read-only tables. Or some virtual table implementations might allow INSERT or DELETE but not UPDATE. Or some virtual table implementations might limit the kinds of UPDATEs that can be made.

Example of virtual tables, already included in the SQLite3 engine, are FTS or RTREE tables. A custom virtual table might represent in-memory data structures (like TSQLVirtualTableJSON, TSQLVirtualTableBinary). Or it might represent a view of data on disk that is not in the SQLite3 format (e.g. TSQLVirtualTableLog). Or the application might compute the content of the virtual table on demand.

Thanks to the generic implementation of Virtual Table in SQLite3, you can use such tables in your SQL statement, and even safely execute a SELECT statement with JOIN or custom functions, mixing normal SQLite3 tables and any other Virtual Table.

A dedicated mechanism has been added to the framework, beginning with revision 1.13, in order to easily add such virtual tables with pure Delphi code, just by inheriting some classes.

Continue reading...

2011, Saturday March 12

TDynArray and Record compare/load/save using fast RTTI

The SynCommons unit has been enhanced:
- new BinToBase64 and Base64ToBin conversion functions;
- new low-level RTTI functions for handling record types: RecordEquals, RecordSave, RecordSaveLength, RecordLoad;
- new TDynArray object, which is a wrapper around any dynamic array.

With TDynArray, you can access any dynamic array (like TIntegerDynArray = array of integer) using TList-like properties and methods, e.g. Count, Add, Insert, Delete, Clear, IndexOf, Find, Sort and some new methods like LoadFromStream, SaveToStream, LoadFrom and SaveTo which allow fast binary serialization of any dynamic array, even containing strings or records - a CreateOrderedIndex method is also available to create individual index according to the dynamic array content. You can also serialize the array content into JSON, if you wish.

What I like with dynamic arrays is that they are reference-counted, don't need any Create/try..finally...Free code, and are well handled by the Delphi compiler.
They are no replacement to a TCollection nor a TList (which are the standard and efficient way of storing class instances), but they are very handy way of having a list of content or a dictionary at hand, with no class nor properties definition.
You can look at them like Python's list, tuples (via records handling) and dictionaries (via Find method), in pure Delphi. Our new methods (about searching and serialization) allow most usage of those script-level structures in your Delphi code.

Continue reading...