Web Application Development Technology

Internet is undoubtedly an important information media, with its rapid development, there will be more and more enterprises, merchants ' Corps, government agencies, schools, scientific research institutions need to establish their own network on the Internet. The construction of a network, hardware needs dedicated servers, hubs, routers, leased data communications with the dedicated line, software needs to install the Internet operating system and Internet servers (WWW, FTP and gopher server), more importantly, You need to write a large number of Internet server applications. This application receives user requests from Internet servers, retrieves data from the internal database, and then transmits the data to the user. Currently widely used on the Internet is the WWW system, the system in HTML file format (that is, commonly called Web pages) to disseminate information, with a Uniform Resource Locator (URL) to connect the world's computer information resources, in accordance with the HTTP protocol between the browser and the WWW server communication. The WWW server is also known as a Web server, and the appropriate server application is called a Web application. Under the Windows operating system, Web applications can be divided into two types: CGI (commongateinterface) Applications and ISAPI (NSAPI) applications. The functions of the two applications are the same, they are received by the Web server to send the user request, to respond to the user needs of data as a Web page or other forms of transmission to the user. The difference is that the former uses standard input output or files to transfer information between Web servers and Web applications, which is a dynamic Join Library program (DLL) whose data can be accessed directly by the Web server. ISAPI refers to Microsoft's Internet Information Server (IIS) programming interface, while NSAPI refers to Netscape's Internet servers programming interface. This article will take the Borland company's C++builder to write an ISAPI (NSAPI) program as an example to introduce the principles and methods of developing Web applications. This application runs under the 32-bit Windows operating system, and if the dot uses WindowsNT, it has IIS (including WWW, FTP, gopher three servers), which is easy to develop and run.

HTTP protocol and HTML specification