Hello Python Community.

I’m pleased to announce pyxser-1.4.4r, a python extension which contains functions to serialize and deserialize Python Objects into XML. It is a model based serializer. Here is the ChangeLog entry for this release:

1.4.4r (2010.02.10):

        Daniel Molina Wegener 

        * src/include/pyxser_collections.h - added set handling
        function prototypes. Added support for unicode
        key names, which are converted to the user settings
        encoding (ie utf-8) inside the XML output.
        * src/pyxser_serializer.c - removed memory leak. Addded
        support for unicode object names in dictionary/list types.
        * src/pyxser_collections.c - added set handling function
        prototypes. added name property handling algorithm, so
        non string name properties are not serialized. I shall
        extend it to other modules.
        * src/pyxser_tools.c - added set handling prototypes and
        set type checking function.
        * test-utf8-leak.py - added serialization of SQL Alchemy
        objects, so we can test more complex Python objects
        serialization.
        * test-utf8-sqlalchemy.py - added sql alchemy object
        serialization test.
        * src/pyxser_serializer.c - reduced serialization algorithms,
        replacing deep nested if statements by flatten ones.
        * src/pyxser_collections.c - reduced serialization algorithms
        replacing deep nested if statements by flatten ones.
        * src/pyxser_typem.c - reduced serialization algorithms,
        replacing deep nested if statements by flatten ones.

        Thanks to pyxser users for their feedback.

This release contains some bug fixes, mainly related to type checking and type handling. I hope this small extension will help you on your programming tasks.

• The project is hosted at:
  http://sourceforge.net/projects/pyxser/
• The web page for the project is located at:
  http://coder.cl/products/pyxser/
• PyPi entry is:
  http://pypi.python.org/pypi/pyxser/1.4.4r
• For a sample article on how to integrate pyxser with ZSI WebServices:
  http://coder.cl/2009/10/18/pyxser-and-zsi-webservices/

Thanks and best regards…

I hope that this module can help you in your development tasks and thanks for your feedback.

Copyright © 2010 Daniel Molina Wegener
Atribución-No Comercial-Sin Derivadas 2.0 Chile

© Daniel Molina Wegener for coder . cl, 2010. | Permalink | No comment
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control classes and interfaces

We can hold our business logic on separate classes. As example we will use a bank loan application, which is supposed to bring us the proper load for certain kind of customers of a bank. So, we need to define an interface pf the loan component.

interface Loan {
    void setUserData(User bankUser);
    void setCustomerData(Customer cus, Account acc);
    LoanResults getLoanResults();
}

This simple interface should be implemented by a variety of Loan types, from consumer ones to mortgage ones, since this variety of loans have different evaluation and estimation logic.

Now we need to define a way to instantiate the proper Loan implementation. The proper Loan implementation request is on the hands of the control layer, since the Loan interface is the abstraction layer itself. So, if we have to need the same methods for every Loan that we request, we just use a Factory Pattern returning the interface Loan, instead of his real implementation.

the abstraction layer

The abstraction layer is implemented on the Loan interface and its returning implementation based on the factory pattern. So we need to implement the factory outside of the package that holds that set of interfaces and implementations. The factory also hold the logic that decides which Loan implementation will be returned, based on the user data, customer data and account data. So we need a call similar to this one:

Loan loanRequest = LoanFactory.getInstance(data);
LoanResults requestResults = loanRequest.getLoanResults();

So, the factory and the loan interface holds the abstraction layer, separating the decoupling the business logic from its real implementation and generating more cohesion. What does the loan request form in the application about those components? The answer is quiet simple: nothing. We will use another pattern to hold input data and pass it through the abstraction layer from the presentation layer. Here is when we are doing dependency injection.

the presentation layer

The presentation layer, which in this case holds a simple LoanRequestForm will never know which concrete class will be used to deliver the LoanResults, so we have to define an instance of another pattern, an Adapter. The adapter should transform the input data from the LoanRequestForm to some kind of Data Transfer Object, to be passed to the factory as CustomerData.

class LoanRequestForm {
    protected Customer cus;
    protected User usr;
    protected Account acc;
    protected LoanRequestFormAdapter adapter = new LoanRequestFormAdapter();
    protected Loan loanRequest;

    LoanResults getLoanResults() {
        try {
            loanRequest = LoanFactory.getInstance(adapter.transform(this));
            LoanResults requestResults = loanRequest.getLoanResults();
            return requestResults;
        } catch (InvalidDataException ex) {
            log.error(ex);
        }
    }
}

Here we are injecting a dependency for the LoanRequestForm and also we acquiring abstraction through the LoanFactory, transforming its input using the LoanRequestFormAdapter to transform the form data into a DTO (Data Transfer Object). The business logic is completely separated from the its User Interface and the abstraction layer. So we are fitting the model with PAC pattern and the IoC DI pattern at once.

The transformation between the form and the factory is a must. The factory can not depend on the form and the form can not depend on the factory. The adapter plays an important role here, since it’s separating layers and transforming the application into an n-tier architected application, so we have more control over changes and possible enhancements on the model. Also it will bring us possible automated processes, since the factory do not needs the form to operate over the loan. So you build another application that just handles the user data and generate loan bids automatically to the customers based on the same logic, then we are reusing the properly the code.

conclusion

We can glue the PAC pattern with IoC DI pattern, so we have more reliable and flexible GUI implementations, then we can work in our platforms without worries about how to generate reusable code if we follow well designed and well applied patterns. Also we can use frameworks, but it depends on the application size and how do need to work on it. For an application with just two active forms, we do not need large scale architectures.

Copyright © 2010 Daniel Molina Wegener
Atribución-No Comercial-Sin Derivadas 2.0 Chile

© Daniel Molina Wegener for coder . cl, 2010. | Permalink | No comment
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• Correctness:

  Software correctness can be established using many techniques and tools, from static analysis, runtime checkers and formal verification. So we have enough tools to determine whether or not the software is correct. Also we can search for the proper algorithm, previously verified and tested to being used in our software.

• Robustness:

  We must try to create small and efficient code, regarding correctness and documenting it, so can create hardened code based on common standards to allow reliable modifications while we are maintaining the code. Jon Postel‘s law says: "Be conservative in what you do; be liberal in what you accept from others". This also reduces the amount of bugs that you can find on your applications.

• Efficiency:

  Efficient code has lower times and reduced cyclomatic complexity. For example we must prefer a construct that is O(1) instead of one that is O(n), if it is available, and we must prefer a construct that has a cyclomatic complexity of 78 rather than other with 129: "simplicity is divine".

• Portability:

  The code must be portable. To create portable code we must simply omit the usage of language/platform specific features. There many standards that we can follow to create portable code and there also are compiler options to help us in that task. For example, GCC supports pedantic compiling flags to regard the strictness of some standards, try compiling your C code with: -Wall -Wextra -Wshadow -pedantic -std=c99, or your C++ code with: -Wall -Wextra -Wshadow -pedantic -std=c++98. Also there is a compiler with the portability issue in mind, the TENDRA compiler, it comes with a static analysis tool too.

• Expressiveness:

  We must create legible code, this principle holds well known coding standards, naming conventions and similar scopes on how do we write the code, to let others read your code and understand it with a faster lookup to the documentation. Also documenting the code is a must. I’m sure that you can follow some standard on coding.

• Flexibility:

  We must try to use abstraction in our code, instead of concrete system calls. For example we have dirent on UNIX and WIN32_FIND_DATA on Windows, both structures are completely different and most Win32 API calls aren’t based on any known standard, so we need to create or use some kind of abstraction to access the system calls, like the Façade design pattern, to allow us to omit direct calls and create more flexible code, and easy to maintain.

• Modularity:

  It’s fully recommended that we must think on terms of OOP. For C programmers the book "Object-oriented programming with ANSI-C" possibly is a must read. Modularity bring us the robustness needed to operate on terms of cohesion, like any desired architecture, we want to implement cohesion instead of attachment, so we can create reusable code and modules.

• Discoverability:

  legible and modular code bring us a good discoverability, so we can establish good basis on well known standard APIs, like POSIX, C++0x and many others. This regards the intuitive approach of building portable code, so we can guess about how is called the function or class that we need to use in our problem.

• Transparency:

  In conjunction with modularity, transparency can bring us the proper cohesion between our software components. The proper abstraction layer between the application tiers allow us to create individual components that work together without attachment and with the proper cohesion. So the maintainability of the application becomes higher and easy.

And here comes some questions: How can we measure all those points?; How can we become more strict and bring more reliable applications?. We must follow some steps to reach optimal software development process. The first one is to define the application architecture, so we can handle common problems with the proper architectural patterns. Then we must fit those architectural patterns with the proper design patterns. One time defined the application architecture we must design our components following that architecture. If we are using Agile Methodologies, we need a well defined architecture too, so we can follow a common paradigm on how to solve the problem that the application is solving.

Using third party frameworks or third party libraries is not a bad practice, but we must be constantly following its roadmap, looking the direction that the library or framework is following, so we can handle properly an incoming and imminent update. How to handle that issue?, using abstractions and modularity, which also reduces the amount of bugs. Here some patterns plays an important role in our quality goals, for example the façade, factory and dependency inyection patterns would help us on that task.

conclusion

The more rigorous we are, we can get more reliable software. But sometimes we don’t have enough time or simply we don’t need to be too rigurous, for example we can not apply formal verification to enterprise applications, because usually those applications have millions of lines of code, instead possibly we can deliver just one module at time that has been verified formally. Instead we can use metrics analyzers, static analyzers and runtime checkers to bring us a better approach on how the code is working. You can learn code hardening techniques and debugging techniques to ensure your code too, which will bring you a better code if you get well taught on those topics.

Copyright © 2010 Daniel Molina Wegener
Atribución-No Comercial-Sin Derivadas 2.0 Chile

© Daniel Molina Wegener for coder . cl, 2010. | Permalink | No comment
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As result, we got a nice architecture design, very applicable to most problems present on the platform. Also, I was capable to answer many questions about the enterprise application. Many of those answers were made based on reverse engineering the source code, tracking every step and tracing component execution. Each member was capable to read some books that we recommended with the Project Manager and understand the third party software, like Google Web Toolkit and Apache FOP. The Project Manager was a good leader guiding the team to the right direction on what to read and how self taught those technologies, while I was doing the proper research, then we got a good team response, and being considered as a good provider.

The key on success was nobody was afraid to ask about the enterprise application, so each member of the team was capable to understand how to interact with those layers that were not accessible as source code — like a black box — and that everyone on the team was responsible of learning the techonologies related to the team work: "read that book", "read that blog article", "take a look on this specification" and some other phrases were common on that team, so everyone was capable to understand their own task.

Most questions were channeled directly to the project manager, then I he was capable to answer, the problem was solved on the fly. In other case, the problem was delivered to me as software architect. Also, team members were capable to ask me directly. Also, most questions were made on SCRUM sessions, and few ones were asked outside of those SCRUM sessions. Few books on Software Architecture, JavaEE Design Patterns, Design Patterns and Architectural Patterns, bring us a wide perspective on how to solve most problems for the kind of components that we were developing. So, most problems were found on the black-box-like enterprise application, since we were having few referrals.

Even if one software engineer was considered — before joining the team — as an NNPP or bad programmer, on the team we got a good result. I agree with Phillip G. Armour in his article "In Prise of Bad Programmers", where he treat this problem as an advantage to make stronger teams:

Sometimes the teams are not made up of all superheroes and when the team asserts itself to overcome some limitation, even with its own personnel, it can become better than it would have been without limitations.

All team members were capable to learn about the enterprise application without the pressure of of not having someone supporting them and fear to commit bugs into the VCS. The were constantly improving their skills, by different reasons, but everyone was learning. As spotted Pete Godlife on his article "Live to love Learning":

Your motivation might be to keep yourself fresh, to sharpen your existing skills or simply to satisfy your natural curiosity. Or the reason might be more mercenary: to strengthen your employability, or allow you to move into a programming field you are more interested in.

conclusion

On every new application which requires new components or maintenance, we need to research it, we must invest time looking on how it works, how affects any change and how we can contribute to improve its construction. Analysis capability is learned along the time and acquired by studying applications and code, you can not request a 100% successful development to someone that do not have the proper guide on a large enterprise application, you need someone doing research on it, doing reverse engineering if it is not documented and let the people learn from that member that have the advantage, even if the application looks like this one — which fortunately isn’t the case in this post.

Copyright © 2010 Daniel Molina Wegener
Atribución-No Comercial-Sin Derivadas 2.0 Chile

© Daniel Molina Wegener for coder . cl, 2010. | Permalink | One comment
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pyxser

pyxser have about one year of development, some months doing research, and other months doing development or coding the Python Module.

And the SVN log show an average hour for commits between 22:00 and 23:00

r125 | damowe | 2010-02-10 16:15:49 -0300 (Wed, 10 Feb 2010) | 2 lines
r124 | damowe | 2010-02-10 15:52:31 -0300 (Wed, 10 Feb 2010) | 2 lines
r123 | damowe | 2010-02-10 13:30:15 -0300 (Wed, 10 Feb 2010) | 10 lines
r122 | damowe | 2010-02-02 08:47:07 -0300 (Tue, 02 Feb 2010) | 3 lines
r121 | damowe | 2009-12-26 21:52:49 -0300 (Sat, 26 Dec 2009) | 2 lines
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r117 | damowe | 2009-12-25 15:20:30 -0300 (Fri, 25 Dec 2009) | 4 lines
r116 | damowe | 2009-12-22 20:09:25 -0300 (Tue, 22 Dec 2009) | 5 lines
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r114 | damowe | 2009-12-20 01:38:45 -0300 (Sun, 20 Dec 2009) | 7 lines
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r16 | damowe | 2009-03-19 22:57:46 -0400 (Thu, 19 Mar 2009) | 2 lines
r15 | damowe | 2009-03-19 22:30:56 -0400 (Thu, 19 Mar 2009) | 5 lines
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r5 | damowe | 2009-03-15 17:21:57 -0400 (Sun, 15 Mar 2009) | 2 lines
r4 | damowe | 2009-03-15 17:07:39 -0400 (Sun, 15 Mar 2009) | 2 lines
r1 | damowe | 2009-03-15 15:35:31 -0400 (Sun, 15 Mar 2009) | 2 lines

The project has 6,198 lines of code… a good effort and a good product. During the day I must work on those projects which bring me money, at night and as hobbits I work on my FOSS projects. I have a little time to work on them.

caffeine

caffeine or C Application Framework has 14,177 lines of code, and it is evaluated as one project with three humans working on it, but it is really one, me.

And the SVN log show an average hour for commits between 22:00 and 23:00

r125 | damowe | 2009-09-30 14:45:06 -0400 (Wed, 30 Sep 2009) | 6 lines
r124 | damowe | 2009-09-26 18:49:31 -0400 (Sat, 26 Sep 2009) | 2 lines
r123 | damowe | 2009-09-26 17:46:26 -0400 (Sat, 26 Sep 2009) | 5 lines
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r83 | damowe | 2007-11-10 21:25:58 -0300 (Sat, 10 Nov 2007) | 2 lines
r82 | damowe | 2007-10-07 11:39:55 -0400 (Sun, 07 Oct 2007) | 3 lines
r81 | damowe | 2007-10-07 08:32:09 -0400 (Sun, 07 Oct 2007) | 3 lines
r80 | damowe | 2007-09-30 21:53:52 -0400 (Sun, 30 Sep 2007) | 3 lines
r79 | damowe | 2007-09-19 18:27:20 -0400 (Wed, 19 Sep 2007) | 2 lines
r78 | damowe | 2007-09-18 00:34:21 -0400 (Tue, 18 Sep 2007) | 2 lines
r77 | damowe | 2007-09-17 17:10:57 -0400 (Mon, 17 Sep 2007) | 3 lines
r76 | damowe | 2007-09-15 17:27:45 -0400 (Sat, 15 Sep 2007) | 2 lines
r75 | damowe | 2007-09-08 11:19:19 -0400 (Sat, 08 Sep 2007) | 2 lines
r74 | damowe | 2007-09-02 12:11:38 -0400 (Sun, 02 Sep 2007) | 2 lines
r73 | damowe | 2007-09-02 10:57:54 -0400 (Sun, 02 Sep 2007) | 2 lines
r72 | damowe | 2007-09-02 10:55:09 -0400 (Sun, 02 Sep 2007) | 2 lines
r71 | damowe | 2007-09-02 09:38:43 -0400 (Sun, 02 Sep 2007) | 5 lines
r70 | damowe | 2007-09-02 02:13:20 -0400 (Sun, 02 Sep 2007) | 4 lines
r69 | damowe | 2007-08-31 20:05:06 -0400 (Fri, 31 Aug 2007) | 3 lines
r68 | damowe | 2007-08-26 13:34:53 -0400 (Sun, 26 Aug 2007) | 2 lines
r67 | damowe | 2007-08-26 13:15:04 -0400 (Sun, 26 Aug 2007) | 3 lines
r66 | damowe | 2007-08-26 10:10:19 -0400 (Sun, 26 Aug 2007) | 3 lines
r65 | damowe | 2007-08-25 19:00:10 -0400 (Sat, 25 Aug 2007) | 3 lines
r64 | damowe | 2007-08-19 00:26:00 -0400 (Sun, 19 Aug 2007) | 3 lines
r63 | damowe | 2007-08-18 10:36:16 -0400 (Sat, 18 Aug 2007) | 3 lines
r62 | damowe | 2007-08-15 17:23:28 -0400 (Wed, 15 Aug 2007) | 2 lines
r61 | damowe | 2007-08-13 07:48:31 -0400 (Mon, 13 Aug 2007) | 3 lines
r60 | damowe | 2007-08-12 17:06:08 -0400 (Sun, 12 Aug 2007) | 2 lines
r59 | damowe | 2007-08-12 16:33:09 -0400 (Sun, 12 Aug 2007) | 3 lines
r58 | damowe | 2007-08-12 13:39:59 -0400 (Sun, 12 Aug 2007) | 2 lines
r57 | damowe | 2007-08-12 01:26:32 -0400 (Sun, 12 Aug 2007) | 2 lines
r56 | damowe | 2007-08-11 13:26:10 -0400 (Sat, 11 Aug 2007) | 2 lines
r55 | damowe | 2007-08-11 13:21:17 -0400 (Sat, 11 Aug 2007) | 3 lines
r54 | damowe | 2007-08-06 21:58:22 -0400 (Mon, 06 Aug 2007) | 2 lines
r53 | damowe | 2007-08-04 23:03:06 -0400 (Sat, 04 Aug 2007) | 3 lines
r52 | damowe | 2007-08-04 22:39:10 -0400 (Sat, 04 Aug 2007) | 3 lines
r51 | damowe | 2007-08-04 17:28:45 -0400 (Sat, 04 Aug 2007) | 2 lines
r50 | damowe | 2007-08-04 16:54:48 -0400 (Sat, 04 Aug 2007) | 2 lines
r49 | damowe | 2007-07-29 09:15:12 -0400 (Sun, 29 Jul 2007) | 2 lines
r48 | damowe | 2007-07-28 17:38:23 -0400 (Sat, 28 Jul 2007) | 2 lines
r47 | damowe | 2007-07-16 23:45:16 -0400 (Mon, 16 Jul 2007) | 3 lines
r46 | damowe | 2007-07-16 16:47:06 -0400 (Mon, 16 Jul 2007) | 3 lines
r45 | damowe | 2007-07-15 20:03:51 -0400 (Sun, 15 Jul 2007) | 3 lines
r44 | damowe | 2007-07-15 12:10:35 -0400 (Sun, 15 Jul 2007) | 3 lines
r43 | damowe | 2007-07-02 17:30:56 -0400 (Mon, 02 Jul 2007) | 2 lines
r42 | damowe | 2007-07-02 10:46:27 -0400 (Mon, 02 Jul 2007) | 3 lines
r41 | damowe | 2007-06-30 16:23:19 -0400 (Sat, 30 Jun 2007) | 2 lines
r40 | damowe | 2007-06-23 21:08:20 -0400 (Sat, 23 Jun 2007) | 3 lines
r39 | damowe | 2007-06-23 10:37:22 -0400 (Sat, 23 Jun 2007) | 2 lines
r38 | damowe | 2007-06-23 10:33:24 -0400 (Sat, 23 Jun 2007) | 2 lines
r37 | damowe | 2007-06-22 23:10:58 -0400 (Fri, 22 Jun 2007) | 3 lines
r36 | damowe | 2007-06-20 21:57:34 -0400 (Wed, 20 Jun 2007) | 3 lines
r35 | damowe | 2007-06-18 21:22:26 -0400 (Mon, 18 Jun 2007) | 3 lines
r34 | damowe | 2007-06-17 21:33:13 -0400 (Sun, 17 Jun 2007) | 2 lines
r33 | damowe | 2007-06-17 21:31:58 -0400 (Sun, 17 Jun 2007) | 2 lines
r32 | damowe | 2007-06-17 18:48:40 -0400 (Sun, 17 Jun 2007) | 3 lines
r31 | damowe | 2007-06-17 12:03:32 -0400 (Sun, 17 Jun 2007) | 3 lines
r30 | damowe | 2007-06-17 11:50:15 -0400 (Sun, 17 Jun 2007) | 2 lines
r29 | damowe | 2007-06-16 21:48:05 -0400 (Sat, 16 Jun 2007) | 2 lines
r28 | damowe | 2007-06-16 21:43:38 -0400 (Sat, 16 Jun 2007) | 3 lines
r27 | damowe | 2007-06-09 18:25:07 -0400 (Sat, 09 Jun 2007) | 2 lines
r26 | damowe | 2007-06-09 18:05:07 -0400 (Sat, 09 Jun 2007) | 2 lines
r25 | damowe | 2007-06-09 18:03:56 -0400 (Sat, 09 Jun 2007) | 3 lines
r24 | damowe | 2007-06-03 20:45:25 -0400 (Sun, 03 Jun 2007) | 3 lines
r23 | damowe | 2007-06-03 19:08:34 -0400 (Sun, 03 Jun 2007) | 2 lines
r22 | damowe | 2007-06-03 19:07:35 -0400 (Sun, 03 Jun 2007) | 2 lines
r21 | damowe | 2007-05-21 10:48:01 -0400 (Mon, 21 May 2007) | 2 lines
r20 | damowe | 2007-05-20 22:00:12 -0400 (Sun, 20 May 2007) | 2 lines
r19 | damowe | 2007-05-20 21:45:38 -0400 (Sun, 20 May 2007) | 6 lines
r18 | damowe | 2007-05-20 10:57:12 -0400 (Sun, 20 May 2007) | 2 lines
r17 | damowe | 2007-05-19 22:22:24 -0400 (Sat, 19 May 2007) | 5 lines
r16 | damowe | 2007-05-18 21:41:36 -0400 (Fri, 18 May 2007) | 2 lines
r15 | damowe | 2007-05-14 23:02:09 -0400 (Mon, 14 May 2007) | 3 lines
r14 | damowe | 2007-05-13 12:03:47 -0400 (Sun, 13 May 2007) | 2 lines
r13 | damowe | 2007-05-13 01:01:13 -0400 (Sun, 13 May 2007) | 2 lines
r12 | damowe | 2007-05-12 22:48:18 -0400 (Sat, 12 May 2007) | 2 lines
r11 | damowe | 2007-05-12 22:41:14 -0400 (Sat, 12 May 2007) | 3 lines
r10 | damowe | 2007-05-07 08:57:33 -0400 (Mon, 07 May 2007) | 2 lines
r9 | damowe | 2007-05-03 08:37:04 -0400 (Thu, 03 May 2007) | 3 lines
r8 | damowe | 2007-05-02 20:50:25 -0400 (Wed, 02 May 2007) | 3 lines
r7 | damowe | 2007-05-01 17:43:00 -0400 (Tue, 01 May 2007) | 2 lines
r6 | damowe | 2007-05-01 09:31:08 -0400 (Tue, 01 May 2007) | 2 lines
r5 | damowe | 2007-05-01 09:24:07 -0400 (Tue, 01 May 2007) | 1 line
r4 | damowe | 2007-05-01 09:08:02 -0400 (Tue, 01 May 2007) | 2 lines
r3 | damowe | 2007-05-01 09:05:41 -0400 (Tue, 01 May 2007) | 2 lines
r2 | damowe | 2007-05-01 09:04:51 -0400 (Tue, 01 May 2007) | 2 lines
r1 | damowe | 2007-05-01 09:04:22 -0400 (Tue, 01 May 2007) | 2 lines

Both projects requires effort and research, and both project are not simple ones to handle, since they are written in C, a language difficult to learn and handle… I hope that I can continue the foss development that I’ve started, but seems that I have some health problems now

Copyright © 2010 Daniel Molina Wegener
Atribución-No Comercial-Sin Derivadas 2.0 Chile

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#!/usr/bin/env python
# skype_call.py
import sys
import Skype4Py

def main():
    if len(sys.argv) != 2:
        print "No dialup number\n"
    number = sys.argv[1]
    number = number.strip()
    for n in [' ', '+', '(', ')', "\s", "\t", '-']:
        number = number.replace(n, "");
    number = '+' + number
    print number, "\n"
    skype = Skype4Py.Skype()
    skype.Attach()
    skype.PlaceCall(number)

if __name__ == '__main__':
    main()

Then, on the Kontact configuration, on the address book settings, we configure the path to our script, called skype_call.py, in this case located at my home directory, on my personal scripts folder.

One time configured contact, you can call your contacts just by clicking on their phone numbers. Remember that skype needs the format +country_code—area_code—phone_number, like +56 (2) 555 55 55.

Happy internet calling

Copyright © 2010 Daniel Molina Wegener
Atribución-No Comercial-Sin Derivadas 2.0 Chile

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1.4.2r (2010.02.10):

        Daniel Molina Wegener <dmw at coder dot cl>
        * pyxser_collections.c: Added constraint checks for NULL
        pointers removing nested statements.
        * pyxser.c: Removed nested statements.
        * pyxser_tools.c: Added constratints checks for NULL pointers,
        removed nested statements and added strict checking for lists
        since it was crashing with an ambigous list definition that
        can not be handled by PyList_Check().
        * test-utf8.py: Added tests to determine if it continue
        crashing with module serialization.

        Thanks to pyxser users for their feedback.

I want to bring special thanks to Dariusz Suchojad for his feedback. I’ve fixed some type checking bugs and minor ones. Now pyxser is capable to do module serialization, but not in concrete one, still is not capable to distribute modules, so it is capable to create a simple module representation as XML, under the pyxser serialization model.

I hope that it will help you on your programming tasks.

Copyright © 2010 Daniel Molina Wegener
Atribución-No Comercial-Sin Derivadas 2.0 Chile

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overview

First we need a concrete class implementing the parser, but it needs an abstraction layer and also something which provides the proper parsing states to its internals. Finally we need to expose those extracted tokens outside of this component — the meta-parser.

Clearly the abstraction is made in top of a single template, the control is given from the ParserService class and the presentation is provided through the Token interface with the proper implementations.

substring automaton

Another interesting point is how specific string parsing is implemented. The system uses an FSM, which implements a simple automaton:

So, parsing the left hand token implies parsing the value token and then it states the right hand token, to complete the cycle reaching again the stored value token . This is used to extract substrings. Where every token is configurable with a proprietary language. Finally, the full parser specific implementation is made on top of state machines which are used according the proper configuration representation using thitd party classes and structures, so is possible to extract the required tokens from the input source.

Also, each configuration and parser instances are designed for concurrency. The project will be running on with parallel tasks inside a mutithreaded — and possibly multiprocess — service daemon. Driven by my client schedule, I can not implement wait free algorithms, so I will be using standard operating system provided locks — and more easy to handle algorithms.

in deep with abstractions

Although the PAC pattern is designed for user interfaces, the usage of this pattern to communicate components and generate strong abstraction layers helps a lot on design and maintainability issues. Indeed, this patterns guarantee a reward while we are coding some design patterns. In this case, for example the MetaParser and the ParserService are both an instance of Adapters, where a transformation is made from one layer to other. While MetaParser is a strong abstraction layer for the given implementations.

Finally ParserService provide us the proper way to handle different parsing tasks, so we can determine inside it which abstraction to use though the proper MetaParser instance.

conclusion

The PAC pattern can be used to implement component communications and proper abstraction between application layers, among the usage on user interfaces. Does it falls in other architectural pattern? Anyone knows?.

Copyright © 2010 Daniel Molina Wegener
Atribución-No Comercial-Sin Derivadas 2.0 Chile

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Hello Python Community.

I'm pleased to announce pyxser-1.4, a python extension which
contains functions to serialize and deserialize Python Objects
into XML. It is a model based serializer. Here is the ChangeLog
entry for this release:

---8<---
1.4r (2009.12.26):

        Daniel Molina Wegener 
        * pyxser_typem.c: Added type map serialization and deserialization
        routines and arguments. Now pyxser is able to serialize and
        deserialize objects using custom serialization functions, but
        preserving the pyxser XML schema and the serialization model.
---8<---

The project is hosted at:

http://sourceforge.net/projects/pyxser/

The web page for the project is located at:

http://coder.cl/products/pyxser/

PyPi entry is:

http://pypi.python.org/pypi?name=pyxser&version=1.4r&:action=display

For a sample article on how to integrate
pyxser with ZSI WebServices:

http://coder.cl/2009/10/18/pyxser-and-zsi-webservices/

Thanks and best regards,
--
| Daniel Molina  |
| IT Consulting & Software Development    |
| http://coder.cl/                        |

I hope that this Python Extension will help you in your development tasks. For any kind of feedback, follow the pyxser announcement thread on comp.lang.python or the Python mailing lists. Another options is simply to create a thread on SourceForge forums or write an email directly to ‘Daniel Molina Wegener’ <dmw@coder.cl>

Copyright © 2009 Daniel Molina Wegener
Atribución-No Comercial-Sin Derivadas 2.0 Chile

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def create_string_from_string(mystr, myroot):
    return str(mystr)

my_typemap = {'java.lang.String': create_string_from_string,
              'String': create_string_from_string,
              'string': create_string_from_string}

unserialized = pyxser.unserialize(obj = serialized, \
                                  enc = "utf-8", \
                                  typemap = my_typemap)

This will allow you to create the proper instance of non standard objects in Python. For example if there exists a third party class which needs a special instantation, like the ones which are using sockets or files, this will allow you to create the instance with a custom function, specially if the serialized object comes from other languages.

The type map callbacks will be called using my_typemap['maptype'](python_string, root_object), where python_string is the node content as Python String and root_object is the deserialized root object — the pointed by the root element. About the error occurrences, I will clear each error produced inside the type map function, by call PyErr_Clear(), then you must control those errors produced inside your callback, and return Py_None (None) on each one.

I will be writing this feature this week and the weekend, if you want a change over this feature, this is the time to get some feedback. I think that pyxser-1.4r will be launched on 2010-01-01.

Copyright © 2009 Daniel Molina Wegener
Atribución-No Comercial-Sin Derivadas 2.0 Chile

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