Thread Safe Implementation of GNU gettext
There is widely available software internationalization tool called GNU gettext. Is is used as base for almost all FOSS software tools. It has binding to almost every language and supports many platforms including Win32.
How does it works? In any place you need to display a string that may potentially show in other language then English you just write:
printf(gettext("Hello World\n"));
And you get the required translation for this string (if available).
In 99% of cases this is good enough. However, as you can see, there is no parameter "target language". It is defined for entry application.
What happends if you need to display this string in different languages? You need to switch locale, and this operation is not thread safe. In most of cases you do not need to do this, because almost all applications will "talk" in single language that user had asked. However this is not the case of web based applications.
Certain web application allow you to display content in several languages: think of government site that should display information in three languages: Hebrew, Arabic and English. So you may need to define the translation per each session you open or use.
So, if you write a multithreaded FastCGI application that supports different languages is signle instance you can't use gettext.
more...The Roadmap to The First Beta Version of CppCMS
After quite a long period of development I had decided to get prepared to first public beta release of CppCMS.
The major components of this blog and the framework I want to introduce in first beta are following:
- Implementation of Django style templates inheritance, filters (done 70%)
- Introduce powerful cache system (done 100%)
- Replace SOCI by LibDBI (done 100%)
- Improve blog: true markdown, LaTeX equations, categories etc. (done 100%)
- Write Documentation (done 20%)
- Migrate my Hebrew blog from Word Press to CppCMS (done 100%)
There are lots of work to do, but CppCMS now looks much mature then before.
more...New Templates System
New templates system was introduces to the CppCMS framework. It is based on ideas of dynamic typed languages inside static typed C++.
The original template system had several problems:
- The each template variable was referenced by and integer key that was generated during compilation of templates.
- The rendering process required from the developer some kind of activity -- update content values according to requests from rendering engine.
- The values of the entries where limited to string, integer and boolean values.
In any case, the design of the first template system was just unacceptable, thus new template system was build.
It introduced following features:
- Dynamic typed variable values using boost::any. They allow assigning of any kind of objects to the variables and rendering them to the templates using custom engines.
- All the variables are references by their names.
- Content now has hierarchical structure when each variable can include list of items or callbacks that allow one step template rendering.
- The design of the engine is now much more modular.
Additional features I'm still working on them are:
- Support of different filters like "html escaping", "urlizing" etc.
- Support of custom filters, including filter chains.
- Support of localization and translation.
SOCI or DBI, stage 2
Discussing soci performance with its developers I had found that soci is compiled without any optimizations by default.
So, after recompiling soci with -O2 option I've got much better results. Simple comparison of dbixx and soci had given very close result. I had run my tests once more and got following results -- pages per second (no gzip): DB soci dbixx -------------------- MySQL 710 800 Sqlite3 550 410 PgSQL 385 430
We can clearly see that for MySQL and PostgreSQL dbixx is still faster in about 10% however in case of Sqlite3 dbixx is significantly slower (25%).
So it seems to me that both solutions are quite reasonable to use without clear advantage of one over another.
SOCI or DBI
One of the problematic issues in writing cross-SQL code is an API that differs from one SQL to another.
There are two open source libraries that provide unified API
At the first point I had chosen soci as native solution of C++ programmer. After running some benchmarks on the new version of this blog I had found 20% performance reduction for MySQL database. But I also remembered that there should be negligible difference between MySQL and Berkeley DB. This was mostly due to incorrect design of my BDB database layout I had done.
That had seem to be strange and I stared benchmarking the system more and more.
more...
