Python Programming On Win32: Help for Windows Programmers

by Mark Hammond, Andy Robinson

Overview

Python is growing in popularity; based on download statistics, there are now over 450,000 people using Python, and more than 150,000 people using Python on Windows. Use of the language has been growing at about 40% per year since 1995, and there is every reason to believe that growth will continue. Despite Python's increasing popularity on Windows, Python Programming on Win32 is the first book to demonstrate how to use it as a serious Windows development and administration tool. Unlike scripting on Unix, Windows scripting involves integrating a number of components, such as COM or the various mail and database APIs, with the Win32 programming interface. While experienced Windows C++ programmers can find their way through the various objects, most people need some guidance, and this book is it. It addresses all the basic technologies for common integration tasks on Windows, explaining both the Windows issues and the Python code you need to glue things together. Topics include:

• The Python language and the PythonWin extensions
• Building a GUI with COM
• Adding a Macro language
• Distributing the application
• Client-side COM for output and data access
• Integration with mail and other internet protocols
• Managing users and drives

This is a vital and unique book. Python Programming on Win32 is an excellent presentation of Windows application development and a solid illustration of how to use Python in the Windows environment.

Product Details

ISBN-13:	9781565926219
Publisher:	O'Reilly Media, Incorporated
Publication date:	02/28/2000
Pages:	672
Product dimensions:	7.00(w) x 9.19(h) x 1.29(d)

About the Author

Mark Hammond is an independent Microsoft Windows consultant working out of Melbourne, Australia. He studied computer science at the South Australian Institute of Technology (now the Universityof South Australia), and then worked with several large financial institutions in Australia. He started his consulting operation in 1995. Mark has produced many of the Windows extensions for Python, including PythonWin, Active Scripting, and Active Debugging support, and coauthored the COM framework and extensions. He is also a leading authority on Active Scripting and related technologies and has spoken on this subject at Microsofts three most recent Professional Developers conferences. Apart from being a father to his teenage daughter, having an interest in live music, and providing way-too-many free Python extensions, Mark has no life!

Andy Robinson is a London-based consultant specializing in business analysis, object-oriented design, and Windows development. He studied physics and philosophy, then Japanese studies at Oxford. He spent a year in advertising in Tokyo, two more in investment banking, and a long spell as the finance director of a startup in the sports industry. Observing that in all these positions he always ended up having to rewrite software, he moved to full-time computer consulting four years ago. He is currently helping one of the world's largest fund managers to internationalize their systems to handle Asian languages, developing Python systems for financial analysis, and reporting. Back when Andy had spare time, his passions were track and field, and rock climbing. Right now his two sons, Tim and Harry, are taking up all of his time.

Read an Excerpt

Chapter 1: Introduction

Case Studies of Python Deployment

Throughout this book we will talk about cases where Python has solved problems in the real world. Both of the authors use Python in their daily work and we will present a couple of examples how we are personally using Python to solve real world problems.

A Japanese Python?

One of the authors is currently working for a global investment company which is internationalizing its core applications to work with Far Eastern markets. The company's client platform is Windows, and core data is stored on Sybase servers and AS400 minicomputers, data flows back and forth among all three platforms continually. All three of these systems represent Japanese characters in totally different ways and work with different character sets. It was necessary not only to develop a library to convert between these encodings, but also to prove that it worked with 100% effectiveness for all the data that might be encountered in future years.

The first stage was to code up the conversions in Python, based on published algorithms and lookup tables. The interactive prompt let us look at the input and output strings very early on and get all of the details right working with single, short strings. We then developed classes to represent character sets' and character maps and fed in the published government character sets - very easy to do with Python's lists and dictionaries. We found subtle holes in published information and were able to correct for them. Having done this, we were able to prove that round-trip conversion was possible in many cases, and to identify the characters which would not survive a round trip in others.

An experienced C++ programmer then wrote a DLL to carry out String translations at high speed. Having a Python prototype allowed us to test the output very early on and compare the output. Python also generated test data sets with every valid character, something that would have taken months by hand. A Python wrapper was written around the DLL, and we wrote scripts to perform heavy-duty tests on it, feeding large customer databases through all possible conversions and back to the start. Naturally the tests uncovered bugs, but we found them all in two days rather than in months.

The DLL was then put to work converting large amounts of report data from mainframe to PC formats. Initially, a Python program used the DLL to perform translations. It would scan for files, decide what to do with them based on the names, break them up, and convert them a field at a time, and manage FTP sessions to send the data on to a destination database server. It also generated a web page for each file translated displaying its contents in an easy-to-read table, along with the results of basic integrity checks. This enabled testing of the data by users on two continents on a daily basis. When the data and algorithms were fully tested and known to be in their final shape, a fairly junior developer with six months experience wrote the eventual C++ program in under a week.

There's a Python on the Scoreboard!

A number of large sports stadiums in Australia (including the two largest with 100,000 person capacities) run custom scoreboard control software during all matches. This software is responsible for keeping and displaying the score for the game (including personal player information), and displaying other messages and advertising during the match. The information is displayed to the huge video scoreboards installed, as well as smaller strip scoreboards located around the ground and locally to the scorers PC using HTML.

The system runs on Windows NT computers, and needs to talk to a variety of custom software and hardware, including custom input device for score keeping and custom hardware to control the video and strip scoreboards. The system also needs to be able to read data during the game from an external database which provides detailed game statistics for each player.

The scoreboard software is written in C++ and Python. The C++ components of the system are responsible for keeping the match score, and maintaining the key score database. All of the scoreboard output functionality is written in Python, and exposes Python as a macro language for the scoreboard operators.

Each output device (for example, the video screen, strip scoreboard or HTML file) has a particular "language" that must be used to control the output. HTML, for example, uses <TAGS>, while the video scoreboard uses a formatting language somewhat similar to postscript. A common thread is that all output formats are text based.

A scheme has been devised that allows the scoreboard operator to embed Python code in the various layout formats. As the format is displayed, the Python code is executed to substitute the actual score. For example, the scoreboard operator may design a HTML page with code similar to

| <P>The player name is <I><%= player.Name %></I>

Anything within the <% tag is considered Python code, and the value substituted at runtime. Thus, this single HTML layout can be used to display the information for any player in the game.

The nature of Python has allowed this to provide features that would not be possible using other languages. One such feature is that the scoreboard operator is free to create new database fields for a player using Microsoft Access and use them in the scoreboard layouts immediately using player.FieldName syntax; thus the object model exposed to the user is actually partially controlled by the user. The use of Python also allows arbitrary code to be executed to control the formatting. For example, the scoreboard operator may use the following HTML to display the list of players in the home team:

|<p>Team <% = home.Name %>
|<% for player in home.Players: %>
|<P><%= player.Name %>
|<% #end %>

This has resulted in a situation programmers strive for, but see all too rarely; a system with enough flexibility that the users are able to do things with your software that you never dreamt could be done!

Other Python' Sightings in the Wild

To further dispel any impressions that Python is new, immature, or unsuited to critical applications, we've included a very small selection of projects and organizations using Python in the real world. These have been culled from a much longer list on the main Python web site., http:www.python.org/

• NASA's Johnson Space Center uses Python as the scripting language for its Integrated Planning System.
• UtraSeek Server, Infoseek's commercial web search engine, is implemented as a Python application, with some C extensions to provide primitive operations for fast, indexing and searching. The core product involves 11,000 lines of Python, and the user interface consists of 17,000 lines of Python-scripted HTML templates.
• The Red Hat Commercial Linux distributions use Python for their installation procedures.
• Caligari Corporation's 3D modeling and animation package, trueSpace 4, uses Python as a scripting language. Users can create custom modelling and animation effects, write interactive applications and develop game prototypes entirely inside trueSpace 4. We'll show you how to do something similar for your own applications in Part 2.
• IBM's East Fishkill factory uses Python to control material entry. exit, and data collection for an entire semiconductor plant.
• Scientists in the Theoretical Physics department of Los Alamos National Laboratory are using Python to control large-scale physics computations on massively parallel high-end servers and clusters. Python plays a central role in controlling simulations, performing data analysis and visualization.
• SMHI, the Swedish civilian weather, hydrological, and oceanographic organization, uses Python extensively to acquire data, analyze it and present it to outside interests such as the media. They are developing a Python-based "Radar Analysis and Visualization Environment" to use with the national network of weather radars.

...

Table of Contents

Preface

I. Introduction to Python

1. What Is Python?
Language Features
Python as an Integration Tool
Case Studies of Python Deployment
The Python Community
Installation and Setup
Conclusion

2. Python Language Review
A Crash Course
Conclusion
References

3. Python on Windows
The Python Core on Windows
The Python for Windows Extensions
The Python Imaging Library (PIL)
PyOpenGL
Web Publishing Tools
The mx Extensions
Scientific Tools
XML
Conclusion

4. Integrated Development Environments for Python
The PythonWin IDE
IDLE
Conclusion

5. Introduction to COM
What It Is
Using COM Objects from Python
Implementing COM Objects with Python
Globally Unique Identifiers
Conclusion

II. Building an Advanced Python Application

6. A Financial Modeling Toolkit in Python
Doubletalk
A Crash Course in Accounting
The Doubletalk Toolkit at Work
Conclusion

7. Building a GUI with COM
Designing COM Servers
A VB Client
Writing a Delphi User Interface
Conclusion

8. Adding a Macro Language
Dynamic Code Evaluation
Making an Application Extensible
Conclusion

9. Integration with Excel
Client-Side COM and the Excel Object Model
Excel Concluded
Putting It All Together: Importing Financial Data
Server-Side COM Again: Excel as a GUI
Conclusion
References

10.Printed Output
Business Requirements
Automating Word
Direct Output to the Printer with Windows
PIDDLE: A Python Graphics API
PostScript
Portable Document Format
Putting It Together: A High-Volume Invoicing System
Conclusion
References

11. Distributing Our Application
DCOM
Conclusion

III. Python on Windows Cookbook

12. Advanced Python and COM
Advanced COM
Python and COM
Using Automation Objects from Python
Using Other COM Interfaces
Error Handling
Implementing COM Objects in Python
Python and DCOM
Conclusion

13. Databases
DAO, ADO, ODBC, OLEDB, and Other GBFLAs
Python's Database API
Getting at Your Data
A Note on Speed
Gadfly, the Pure Python Relational Database
Data Laundering with Python
A Three-Tier Architecture with Business Objects
Conclusion
References

14. Working with Email
SMTP and POP3
Microsoft Exchange/Outlook
Conclusion

15. Using the Basic Internet Protocols
HTTP and HTML
FTP
NNTP
Conclusion

16. Windows NT Administration
Working with Users and Groups
Server and Share Information
Rebooting a Machine
Conclusion
References

17. Processes and Files
Portable File Manipulation
Native File Manipulation: The win32file Module
Pipes
Processes
Conclusion

18. Windows NT Services
Services in Brief
Controlling Services with Python
Reading the Event Log
Windows NT Performance Monitor Data
Writing Services in Python
Sample Service Written in Python
Writing to the Event Log
Providing Performance Monitor Information
A Final Service
Conclusion

19. Communications
Serial Communications
Remote Access Services
Sockets
Other Communications Tools
Conclusion
References

20. GUI Development
Tkinter
PythonWin
wxPython

21. Active Scripting
Registering the Python Active Script Support
Python and Popular Microsoft Applications
Active Debugging
How Active Scripting Works
Active Script Hosting in Python
Conclusion

22. Extending and Embedding with Visual C++ and Delphi
Python and Visual C++
Simplified Wrapper and Interface Generator
Python and Delphi
Dynamic DLL Access
References
Conclusion

IV. Appendixes

A. Key Python Modules and Functions

B. Win32 Extensions Reference

C. The Python Database API Version 2.0

D. Threads

Index

Editorial Reviews

As more extensions become available, Python is showing up more often in Win32 environments, leaving the UNIX/Linux environment behind. A major product of the OpenSource revolution, Python is an interpreted and interactive object-oriented scripting language. This guide focuses on advanced Python applications, such as accessing databases and working with NT files, processors and services. For best comprehension, you should be familiar with the Python language and the Windows environment. Some Visual Basic background and familiarity with C/C++ is helpful.

Highlights:

• Briefly reviews the syntax and structure of the Python language, including installation and setup in the Windows environment.
• Overviews the Windows specific packages and extensions, specifically the two IDEs for the Win platform, Pythonwin and IDLE.
• Details an advanced Python application based on COM, which is an extensible accounting toolkit embedded in a standard VB interface.
• Demonstrates Excel and Word control via Python and provides a high-volume printing solution for Acrobat's Portable Document Format (PDF).

Advantages:

• Profiles Python's ample opportunities for active scripting, alternative GUI development, RAS and serial I/O communication scripting.
• Discusses how Python complements, but does not compete with, existing tools and utilities in the Win32 environment.

Related Titles:

If you are new to Python we suggest Learning Python to complement this more advanced text. For information on Python extensions andintegration, check out Programming Python.

Demonstrates how to use the Python programming language (an object- oriented scripting language) as a development and administrations tool for Win32. Focused on tasks rather than programming (although a brief tutorial is provided) the authors cover how Python works on Windows; the key integration technologies supported by Python on Windows; and examples of what Python can do with databases, email, Internet protocols, NT services, communications, and other areas. Annotation c. Book News, Inc., Portland, OR (booknews.com)

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