Open Source web application developer Innovation
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Wikipedia
Open-source software development (OSSD) is the process by which open-source software, or similar software whose source code is publicly available, is developed by an open-source software project. These are software products available with its source code under an open-source license to study, change, and improve its design. Examples of some popular open-source software products are Mozilla Firefox, Google Chromium, Android, LibreOffice and the VLC media player.
In 1997, Eric S. Raymond wrote The Cathedral and the Bazaar. In this book, Raymond makes the distinction between two kinds of software development. The first is the conventional closed-source development. This kind of development method is, according to Raymond, like the building of a cathedral; central planning, tight organization and one process from start to finish. The second is the progressive open-source development, which is more like “a great babbling bazaar of differing agendas and approaches out of which a coherent and stable system could seemingly emerge only by a succession of miracles.” The latter analogy points to the discussion involved in an open-source development process.
Differences between the two styles of development, according to Bar and Fogel, are in general the handling (and creation) of bug reports and feature requests, and the constraints under which the programmers are working. In closed-source software development, the programmers are often spending a lot of time dealing with and creating bug reports, as well as handling feature requests. This time is spent on creating and prioritizing further development plans. This leads to part of the development team spending a lot of time on these issues, and not on the actual development. Also, in closed-source projects, the development teams must often work under management-related constraints (such as deadlines, budgets, etc.) that interfere with technical issues of the software. In open-source software development, these issues are solved by integrating the users of the software in the development process, or even letting these users build the system themselves.
Open-source software development can be divided into several phases. The phases specified here are derived from Sharma et al. A diagram displaying the process-data structure of open-source software development is shown on the right. In this picture, the phases of open-source software development are displayed, along with the corresponding data elements. This diagram is made using the meta-modeling and meta-process modeling techniques.
There are several ways in which work on an open-source project can start:
- An individual who senses the need for a project announces the intent to develop a project in public.
- A developer working on a limited but working code base, releases it to the public as the first version of an open-source program.
- The source code of a mature project is released to the public.
- A well-established open-source project can be forked by an interested outside party.
Eric Raymond observed in his essay The Cathedral and the Bazaar that announcing the intent for a project is usually inferior to releasing a working project to the public.
It’s a common mistake to start a project when contributing to an existing similar project would be more effective (NIH syndrome) To start a successful project it is very important to investigate what’s already there. The process starts with a choice between the adopting of an existing project, or the starting of a new project. If a new project is started, the process goes to the Initiation phase. If an existing project is adopted, the process goes directly to the Execution phase.
Several types of open-source projects exist. First, there is the garden variety of software programs and libraries, which consist of standalone pieces of code. Some might even be dependent on other open-source projects. These projects serve a specified purpose and fill a definite need. Examples of this type of project include the Linux kernel, the Firefox web browser and the LibreOffice office suite of tools.
Distributions are another type of open-source project. Distributions are collections of software that are published from the same source with a common purpose. The most prominent example of a “distribution” is an operating system. There are many Linux distributions (such as Debian, Fedora Core, Mandriva, Slackware, Ubuntu etc.) which ship the Linux kernel along with many user-land components. There are other distributions, like ActivePerl, the Perl programming language for various operating systems, and Cygwin distributions of open-source programs for Microsoft Windows.
Other open-source projects, like the BSD derivatives, maintain the source code of an entire operating system, the kernel and all of its core components, in one revision control system; developing the entire system together as a single team. These operating system development projects closely integrate their tools, more so than in the other distribution-based systems.
Finally, there is the book or standalone document project. These items usually do not ship as part of an open-source software package. The Linux Documentation Project hosts many such projects that document various aspects of the Linux operating system. There are many other examples of this type of open-source project.
It is hard to run an open-source project following a more traditional software development method like the waterfall model, because in these traditional methods it is not allowed to go back to a previous phase. In open-source software development, requirements are rarely gathered before the start of the project; instead they are based on early releases of the software product, as Robbins describes. Besides requirements, often volunteer staff is attracted to help develop the software product based on the early releases of the software. This networking effect is essential according to Abrahamsson et al.: “if the introduced prototype gathers enough attention, it will gradually start to attract more and more developers”. However, Abrahamsson et al. also point out that the community is very harsh, much like the business world of closed-source software: “if you find the customers you survive, but without customers you die”.
Fuggetta argues that “rapid prototyping, incremental and evolutionary development, spiral lifecycle, rapid application development, and, recently, extreme programming and the agile software process can be equally applied to proprietary and open source software”. He also pinpoints Extreme Programming as an extremely useful method for open source software development. More generally, all Agile programming methods are applicable to open-source software development, because of their iterative and incremental character. Other Agile method are equally useful for both open and closed source software development:Internet-Speed Development, for example is suitable for open-source software development because of the distributed development principle it adopts. Internet-Speed Development uses geographically distributed teams to ‘work around the clock’. This method, mostly adopted by large closed-source firms, (because they’re the only ones which afford development centers in different time zones), works equally well in open source projects because a software developed by a large group of volunteers shall naturally tend to have developers spread across all time zones.
A web application (or web app) is application software that runs in a web browser, unlike software programs that run locally and natively on the operating system (OS) of the device. Web applications are delivered on the World Wide Web to users with an active network connection.
In earlier computing models like client-server, the processing load for the application was shared between code on the server and code installed on each client locally. In other words, an application had its own pre-compiled client program which served as its user interface and had to be separately installed on each user’s personal computer. An upgrade to the server-side code of the application would typically also require an upgrade to the client-side code installed on each user workstation, adding to the support cost and decreasing productivity. In addition, both the client and server components of the application were usually tightly bound to a particular computer architecture and operating system and porting them to others was often prohibitively expensive for all but the largest applications (Nowadays, native apps for mobile devices are also hobbled by some or all of the foregoing issues).
In 1995, Netscape introduced a client-side scripting language called JavaScript allowing programmers to add some dynamic elements to the user interface that ran on the client side. So instead of sending data to the server in order to generate an entire web page, the embedded scripts of the downloaded page can perform various tasks such as input validation or showing/hiding parts of the page.
In 1999, the “web application” concept was introduced in the Java language in the Servlet Specification version 2.2. [2.1?]. At that time both JavaScript and XML had already been developed, but Ajax had still not yet been coined and the XML Http Request object had only been recently introduced on Internet Explorer 5 as an ActiveX object.
In 2005, the term Ajax was coined, and applications like Gmail started to make their client sides more and more interactive. A web page script is able to contact the server for storing/retrieving data without downloading an entire web page.
Applications are usually broken into logical chunks called “tiers”, where every tier is assigned a role. Traditional applications consist only of 1 tier, which resides on the client machine, but web applications lend themselves to an n-tiered approach by nature. Though many variations are possible, the most common structure is the three-tiered application. In its most common form, the three tiers are called presentation, application and storage, in this order. A web browser is the first tier (presentation), an engine using some dynamic Web content technology (such as ASP, CGI, ColdFusion, Dart, JSP/Java, Node.js, PHP, Python or Ruby on Rails) is the middle tier (application logic), and a database is the third tier (storage). The web browser sends requests to the middle tier, which services them by making queries and updates against the database and generates a user interface.
For more complex applications, a 3-tier solution may fall short, and it may be beneficial to use an n-tiered approach, where the greatest benefit is breaking the business logic, which resides on the application tier, into a more fine-grained model. Another benefit may be adding an integration tier that separates the data tier from the rest of tiers by providing an easy-to-use interface to access the data. For example, the client data would be accessed by calling a “list_clients()” function instead of making an SQL query directly against the client table on the database. This allows the underlying database to be replaced without making any change to the other tiers.
There are some who view a web application as a two-tier architecture. This can be a “smart” client that performs all the work and queries a “dumb” server, or a “dumb” client that relies on a “smart” server. The client would handle the presentation tier, the server would have the database (storage tier), and the business logic (application tier) would be on one of them or on both. While this increases the scalability of the applications and separates the display and the database, it still doesn’t allow for true specialization of layers, so most applications will outgrow this model.
Security breaches on these kinds of applications are a major concern because it can involve both enterprise information and private customer data. Protecting these assets is an important part of any web application and there are some key operational areas that must be included in the development process. This includes processes for authentication, authorization, asset handling, input, and logging and auditing. Building security into the applications from the beginning can be more effective and less disruptive in the long run.
Writing web applications is often simplified with the use of web application frameworks. These frameworks facilitate rapid application development by allowing a development team to focus on the parts of their application which are unique to their goals without having to resolve common development issues such as user management. Many of the frameworks in use are open-source software.
The use of web application frameworks can often reduce the number of errors in a program, both by making the code simpler, and by allowing one team to concentrate on the framework while another focuses on a specified use case. In applications which are exposed to constant hacking attempts on the Internet, security-related problems can be caused by errors in the program. Frameworks can also promote the use of best practices such as GET after POST.
In addition, there is potential for the development of applications on Internet operating systems, although currently there are not many viable platforms that fit this model.