Netscape Server Application Programming Interface

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The Netscape Server Application Programming Interface (NSAPI) is an application programming interface for extending server software, typically web server software.

An application programming interface (API) is an interface or communication protocol between a client and a server intended to simplify the building of client-side software. It has been described as a “contract” between the client and the server, such that if the client makes a request in a specific format, it will always get a response in a specific format or initiate a defined action.

Software Non-tangible executable component of a computer

Computer software, or simply software, is a collection of data or computer instructions that tell the computer how to work. This is in contrast to physical hardware, from which the system is built and actually performs the work. In computer science and software engineering, computer software is all information processed by computer systems, programs and data. Computer software includes computer programs, libraries and related non-executable data, such as online documentation or digital media. Computer hardware and software require each other and neither can be realistically used on its own.

Web server server that serves website content to clients

A web server is server software, or hardware dedicated to running said software, that can satisfy World Wide Web client requests. A web server can, in general, contain one or more websites. A web server processes incoming network requests over HTTP and several other related protocols.

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History

NSAPI was initially developed by Rob McCool at Netscape for use in Netscape Enterprise Server. A variant of NSAPI can also be used with Netscape Directory Server.

Netscape is a brand name associated with the development of the Netscape web browser. It is now owned by Verizon Media, a subsidiary of Verizon. The brand belonged to the Netscape Communications Corporation, an independent American computer services company, whose headquarters were in Mountain View, California, and later Dulles, Virginia. The browser was once dominant but lost to Internet Explorer and other competitors after the so-called first browser war, its market share falling from more than 90 percent in the mid-1990s to less than 1 percent in 2006.

Because there is no formal standard, applications that use NSAPI are not necessarily portable across server software. As of 2007, varying degrees of support for NSAPI are found in Sun Java System Web Server and Zeus Web Server.

Zeus Web Server was a proprietary web server for Unix and Unix-like platforms. It was developed by Zeus Technology, a software company located in Cambridge, England. The original authors and company founders are University of Cambridge graduates Damian Reeves and Adam Twiss.

NSAPI plug-ins

Applications that use NSAPI are referred to as NSAPI plug-ins. Each plug-in implements one or more Server Application Functions (SAFs).

Plug-in (computing) software component that adds a specific feature to an existing software application

In computing, a plug-in is a software component that adds a specific feature to an existing computer program. When a program supports plug-ins, it enables customization.

To use a SAF, an administrator must first configure the server to load the plug-in that implements that SAF. This is typically controlled by a configuration file named magnus.conf. Once the plug-in is loaded, the administrator can configure when the server should invoke the SAF and what parameters it should be passed. This is typically controlled by a configuration file named obj.conf.

System administrator Person who maintains and operates a computer system and/or network

A system administrator, or sysadmin, is a person who is responsible for the upkeep, configuration, and reliable operation of computer systems; especially multi-user computers, such as servers. The system administrator seeks to ensure that the uptime, performance, resources, and security of the computers they manage meet the needs of the users, without exceeding a set budget when doing so.

Configuration file software file used to configure the initial settings for a computer program

In computing, configuration files are files used to configure the parameters and initial settings for some computer programs. They are used for user applications, server processes and operating system settings.

NSAPI can be compared to an earlier protocol named Common Gateway Interface (CGI). Like CGI, NSAPI provides a means of interfacing application software with a web server. Unlike CGI programs, NSAPI plug-ins run inside the server process. Because CGI programs run outside of the server process, CGI programs are generally slower than NSAPI plug-ins. However, running outside of the server process can improve server reliability by isolating potentially buggy applications from the server software and from each other.

In computing, Common Gateway Interface (CGI) offers a standard protocol for web servers to execute programs that execute like console applications running on a server that generates web pages dynamically. Such programs are known as CGI scripts or simply as CGIs. The specifics of how the script is executed by the server are determined by the server. In the common case, a CGI script executes at the time a request is made and generates HTML.

Application software computer software designed to perform a group of coordinated functions, tasks, or activities for the benefit of the user

Application software is software designed to perform a group of coordinated functions, tasks, or activities for the benefit of the user. Examples of an application include a word processor, a spreadsheet, an accounting application, a web browser, an email client, a media player, a file viewer, an aeronautical flight simulator, a console game or a photo editor. The collective noun application software refers to all applications collectively. This contrasts with system software, which is mainly involved with running the computer.

Computer program Instructions to be executed by a computer

A computer program is a collection of instructions that performs a specific task when executed by a computer. Most computer devices require programs to function properly.

In contrast to CGI programs, NSAPI SAFs can be configured to run at different stages of request processing. For example, while processing a single HTTP request, different NSAPI SAFs can be used to authenticate and authorize the remote user, map the requested URI to a local file system path, generate the web page, and log the request.

After Netscape introduced NSAPI, Microsoft developed ISAPI and the Apache Software Foundation developed Apache API (or ASAPI: Apache Server API). All three APIs have a number of similarities. For example: NSAPI, ISAPI and Apache API allow applications to run inside the server process. Further, all three allow applications to participate in the different stages of request processing. For example, Apache API hooks closely resemble those used in NSAPI. [1]

See also

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Server-side scripting is a technique used in web development which involves employing scripts on a web server which produce a response customized for each user's (client's) request to the website. The alternative is for the web server itself to deliver a static web page. Scripts can be written in any of a number of server-side scripting languages that are available. Server-side scripting is distinguished from client-side scripting where embedded scripts, such as JavaScript, are run client-side in a web browser, but both techniques are often used together.

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Web application application that uses a web browser as a client

In computing, a web application or web app is a client–server computer program which the client runs in a web browser. Common web applications include webmail, online retail sales, and online auction.

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References

  1. ↑ "Apache API notes".
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