Uses for CGI

HTML allows you to access resources on the Internet by using other protocols that are specified in the URL. Examples of such protocols are mailto, ftp, and news. If you code a link with mailto that is followed by an e-mail address, the link will result in a generic mail form.

What if you wanted your customers to provide specific information, such as how often they use the web? Or how they heard about your company? Rather than using the generic mailto form, you can create a form that asks these questions and more. You can then use a CGI program to interpret the information, include it in an e-mail message, and send it to the appropriate person.

You do not need to limit CGI programs to processing search requests and e-mail. You can use them for a wide variety of purposes. Basically, anytime you want to take input from the reader and generate a response, you can use a CGI program.

The input may even be apparent to the reader. For example, many people want to know how many other people have visited their home page. You can create a CGI program that keeps track of the number of requests for your home page. This program can display the new total each time someone links to your home page.

The CGI process

Usually CGI programs are referred to from within HTML documents. In general, the HTML document format defines the environment variables that specify the passing of information. When you design the layout of your HTML document, you must keep in mind how a CGI program might affect the look of your document. Developing the CGI program along with the HTML document will help you avoid many design mistakes.

Overview

The CGI process involves three players: The web browser, the web server, and the CGI program. To exemplify how CGI programs for online forms work, let us assume that the web browser has already requested and obtained an HTML form.

1.The user clicks buttons or enters information in fields, and then clicks on an HTML button to submit the request.

2.The web browser then sends the data to the web server in an encoded format. For example, the data might consist of responses on an HTML form.

3.When the web server receives data, it converts the data to a format compliant with the CGI specification for input and sends it to the CGI program.

4.The CGI program then decodes and processes the data.

5.The system sends this response back to the web server in a form that is compliant with the CGI specification for output.

6.The web server then interprets the response and forwards it to the web browser.

Note: If a CGI application program must change the HTTP server job attributes while processing, the CGI program must restore the attributes to their initial values before the CGI program ends. Failure to restore job attributes that are changed in the CGI program will result in unpredictable responses to future server requests. For example, a CGI program that requires a library in the library list needs to add the library to the library list. The CGI program must remove the library list before the CGI program ends.

Chapter 1. Writing Common Gateway Interface Programs 3

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IBM AS/400E manual Uses for CGI, CGI process, Overview
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AS/400E specifications

The IBM AS/400E, now more commonly known as IBM i, is a robust and versatile midrange server that has been designed to provide a comprehensive computing solution for businesses of all sizes. First introduced in the late 1980s, the AS/400 series has undergone multiple enhancements and rebranding, with the AS/400E being one of the notable iterations. This powerful platform is closely associated with IBM's commitment to reliability, scalability, and integrated business solutions.

One of the main features of the AS/400E is its highly integrated architecture that combines hardware and software into a cohesive system. This integration allows for seamless operations, reducing the complexity typically associated with managing disparate systems. The system is powered by IBM's proprietary OS/400 operating system, which has evolved into IBM i, featuring advanced capabilities like object-oriented programming, integrated database management, and security features that are essential for enterprise environments.

A key characteristic of the AS/400E is its robust database support, primarily through the use of DB2 for i. This integrated database management system enables efficient data handling and retrieval, facilitating real-time business analytics and reporting. Furthermore, the platform supports a variety of programming languages, including RPG, COBOL, and Java, making it flexible for developers who require diverse tools for application development.

The AS/400E is also known for its exceptional reliability and uptime, making it a preferred choice for critical business applications in industries such as finance, healthcare, and manufacturing. This reliability is backed by advanced error detection and correction mechanisms, as well as redundancy features that help prevent data loss and minimize downtime.

In terms of scalability, the AS/400E can effortlessly expand to accommodate growing business demands. Organizations can increase processing power by adding more resources without significant disruption. This scalability, combined with the system’s built-in virtualization capabilities, allows businesses to optimize resource usage and streamline operations.

Security is another defining feature of the AS/400E. The platform incorporates various layers of security measures, including user authentication, encryption, and comprehensive auditing capabilities, ensuring that sensitive business data is protected against unauthorized access.

Overall, the IBM AS/400E remains a powerful tool in the enterprise computing landscape, providing businesses with an integrated, reliable, and secure solution for their technological needs. Its enduring popularity is a testament to its capability to evolve with changing business requirements while maintaining its core attributes of high performance and stability.
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