Data Sheets White Papers/ Python - Language of Choice for EAI Presentations News This article appeared in the January, 2003 issue of the EAI Journal. A PDF version is available here Python- Language of Choice for EAI Most of the hype regarding programming languages for web services is around the competition between C# and Java. But there is one language that both Microsoft and its competitors have all agreed to support in their various platforms: Python. Python has a reputation of being a scripting language like Perl. But in fact, it is a full-featured, highly advanced programming platform, with roots in LISP and Smalltalk. More and more organizations are beginning to adopt Python as the platform of choice for distributed application development. Python is an object-oriented, high-level interpreted language. Python was originally developed in the early '90s by Guido van Rossum. His original goal was to develop a language that could be used to teach the most advanced concepts of programming to non-programmers. As such, the language stresses readability, simplicity and elegance. To quote van Rossum: "As an object-oriented language, Python aims to encourage the creation of reusable code. Even if we all wrote perfect documentation all of the time, code can hardly be considered reusable if it's not readable." Python is also extremely portable. There are currently identical versions available for nearly every computing platform, major and obscure, from PDAs to mainframes. Python is also an open-source platform, which encourages sharing of ideas and code. The combination of simplicity, power and portability, along with its open-source nature, has made Python extremely popular. Over the last decade, still under the guidance of van Rossum, Python has grown from a small teaching project, into a programming language that is used by major enterprises around the world, in mission-critical applications. We group Python advantages by the key features listed above. Please note, that whatever is said below about Java, applies equally to C#. A. Powerful Simplicity Python programs are far quicker to develop than other high-level languages. Because of the elegance and simplicity of the language, Python programs tend to be 3-5 times shorter than their equivalent in Java, and 5-10 times shorter than C++ equivalents. In addition, being an interpreted language eliminates the lengthy edit-compile-debug cycle of other high-level languages. Since programmer costs are the most significant part of any programming project, this advantage alone provides a good reason to consider using Python. Python programs are easier to maintain. The simple, clean syntax not only allows the original developers to remember what they did, it also allows other developers to understand and change programs. This allows for much lower maintenance costs for Python programs. Python is an extremely versatile language. It can be used for the simplest scripting applications, as well as for the development of complex websites, and all the way up to the construction of complex distributed applications. This versatility allows organizations to reduce training and software tool costs. Python's object-oriented paradigm is the most powerful and easy to use of any commercial programming language. Like Smalltalk, Python has dynamic typing and binding, and everything in Python is an object. Object behavior can be adapted at run-time. This allows Python programmers to easily use the full, flexible power of object-orientation, as opposed to Java or C++. However, Python's syntax is more like other standard programming languages, so it is much easier for programmers to learn than Smalltalk. Again powerful simplicity allows for rapid development of more complex applications. B. Portability Python is available on an incredibly wide range of hardware and software platforms. This includes the usual suspects: Sun, Intel, IBM, Microsoft Windows variants, Macintosh OS variants and all Unices. However, Python has also found its way into a wide range of less well-known platforms, including PDAs and set-top boxes. Python is probably the only language where one can truly say, write once and deploy everywhere. Python plays well with other languages. Python programs can be extended using C, C++, or Java, or can be embedded in programs written in these languages. Jython is an implementation of Python written in 100% Pure Java, that allows you to run Python on any Java platform. There is also a Python extension that supports Microsoft's .NET Framework’s Common Language Runtime (CLR). Hence Python code can be used with any web services variant offered by competing vendors. Moreover, in those parts of applications where speed is of the essence, code can be written in the most efficient programming language available, while still retaining the rapid application development advantages of Python. Finally, Python can be used as a wrapper for legacy applications written in other languages.  Python plays well with programming standards. Many high-quality Python extensions are available which support almost all Internet standards, CORBA, COM, SOAP, XML, XML-RPC and so on. Python provides the option for integration with low-level APIs for both the Windows and Unix platforms, allowing applications to be highly platform compatible. Java, by contrast, only gives the option for developing to the lowest common denominator across platforms. C# only gives the option to be Microsoft compatible. C. Free/Open Source Software (FOSS) Thousands of programmers around the world contribute to the development of Python. These programmers are not being paid to develop Python, but are being paid to develop applications. They use Python in real world settings. This ensures that Python is robust, secure, relatively efficient, portable, scalable and has a feature set which meets real world needs, not what vendors think customers should have. Python like all FOSS software has three freedoms: It can be used freely, without paying exorbitant licensing fees. It ensures free development of software applications without any artificially imposed vendor restrictions. It ensures a free software market, eliminating enterprise dependence on any software vendor large or small. D. Other Considerations Several objections are often raised against using Python. We address them here. "There are very few Python programmers." While it is true that there are far more Java programmers currently available, there is also a very large community of programmers who know Python. Since Python is FOSS, enterprises can learn about many of these programmers skills and abilities through their involvement in the Python community. There is often no way to get an idea about a Java programmer's abilities until after they are hired. Moreover, Jython can be used to leverage Java programmer skills and help them migrate to and learn Python. Moreover, Python is easy to learn, especially for programmers already familiar with object-oriented concepts. "Interpreted languages are inefficient." As an interpeted language, Python is in many cases slower than Java, and certainly C++ or C. But as noted earlier, where efficiency really matters, C code can be embedded. For the rest, the Python advantages are clear. "But it's just a programming language!" Python has been extended by a huge number of modules that make it into a system development platform, not just a programming language. There is an enormously successful web-development/application server/content management system, based on Python (Zope). There are also IDEs available, both FOSS and commercial, and many other support tools. "How will I get support for an FOSS system?" Besides the extensive free support available from the Python community there are many vendors who provide commercial support for Python and its extentions. "Nobody is using it!" Python does not yet have the mind share in the enterprise that Java does. So the next section will be devoted to providing just a few of the many success stories around Python. For more extensive information about Python, you can visit the Python website. Here is a list of just some of the enterprises currently using Python Industrial Light & Magic, maker of the Star Wars films, uses Python extensively in the computer graphics production process Google, a leading internet search engine, extensively uses Python. Yahoo uses Python for its groups site. IBM has, among other things, used Python in factory tool control applications. Disney uses Python for its animation production applications. BEA uses Python in testing enterprise-class e-commerce software. NASA uses Python in several large projects, including a CAD/CAM system and a graphical workflow modeler used in planning space shuttle missions. The National Weather Service (USA) uses Python to prepare weather forecasts. Python is also used for this purpose at the Swedish Meteorological and Hydrological Institute and at TV4 Sweden. There are many more such examples. To learn more about the growing use of Python in business, as well as to get information about commercial companies that provide Python consulting, support, training and tools, visit the website of the Python Business Forum. IT managers in companies large and small all face the following problem: On the one hand, applications live forever. Developing applications that meet organizations' needs is the real challenge of any IT shop. Once the application development process has finally worked its way through all the organizational politics, no CIO in his right mind wants to touch it. On the other hand, significant cost savings can often be realized by replacing the IT shop's underlying infrastructure of hardware, OS and networking software every few years. So "middleware" becomes increasingly important as the buffer between the long-lived applications and the underlying infrastructure. But wait, there is more. Management has always wanted various IT applications to inter-operate. But the rise of the Internet just whetted management's appetite for more. Now everything must integrate and work together, within the organization and across organizational boundaries. Middleware becomes even more important as the glue that ties diverse applications together. But the issues become far more complex as applications are now networked and distributed. Web services is touted as the panacea, the ultimate glue that will solve all IT problems. This is not a paper about the limitations of web services. But there are two issues that any IT shop must face: What to do with the huge investment the organization has in legacy applications? How to ensure that the enterprise is not selling its organizational soul to eternal dependence on one particular vendor? The long list of advantages of Python, noted above, directly address these two core issues, and make Python particularly suited as a basis for EAI. Python's high-level, powerful simplicity makes it an excellent choice for abstracting out the complexity of application-infrastructure interaction. It's vast portability and inter-operability with a wide-range of hardware and software, make it the system of choice for wrapping legacy applications. And its FOSS heritage guarantees future freedom from vendor dependence. CIOs can choose infrastructure purely based on price-performance considerations, without having to forever buy into a particular vendor's world. We noted above that Python the language has been extended by many powerful system modules. One of these particularly addresses EAI. More on that in the next section. Twisted is a sophisticated event-driven network FOSS Python-based framework, that provides extremely powerful, scalable and flexible enterprise application integration capabilities. At the core of Twisted is its network layer which can be used to rapidly integrate any existing protocol as well as model new ones. Whenever the need arises to develop a new protocol, the asynchronous, multiplexed and two-way remote object protocol (ROP) can be used to quickly implement it. Because the ROP is used with object-level abstractions, changes can be made easily, and new features added, without having to deal with the design restrictions and application development complexities of a custom protocol. Out of the box, Twisted supports a large number of service protocols: HTTP, FTP, SMTP, LDAP, DNS, SOCKSv4, SSH, IRC, telnet, POP3, AOL's instant messaging and more. This allows developers to use these protocols immediately, without having to spend time re-implementing them. In addition, Twisted can talk to multiple, industry standard DBMS. It also can be used to communicate with COM servers and to control and integrate with standard Windows applications (Word, Excel, etc.). Unlike other frameworks, that are designed to address a specific domain -- email, Web sites, Web services -- Twisted is designed to support both multiple frameworks and multiple protocols at the same time. Thus, Twisted can be used to implement web sites, web services, email servers, or instant messaging servers. Moreover, these services can all run in the same process. For more information about Twisted, visit the Twisted Matrix website. Hopefully, at the end of this very brief overview of Python, you have understood that it is an excellent choice for software development in general, and EAI in particular. One important point to note is that the barrier to entry of Python is very low. Python software and introductory tutorials and texts are available for free, as in beer. So is basic Python support. In the words of that famous commercial: "Try it, you'll like it."