Apple WebObjects 3.5: Serving - Manual (Page 3)

Serving WebObjects
4
Installation Guide is printed and included with the WebObjects CD-ROM or
can be downloaded from NeXTanswers; it is not online).
• Post-Installation Instructions: Describes how to verify the installation and
troubleshoot if WebObjects applications do not run.
WebObjects HTTP Adaptors
A key part of WebObjects administration is dealing with adaptors. This section
provides a little background material on what a WebObjects HTTP adaptor is,
how it works, and how you can configure it to suit your needs.
A WebObjects HTTP adaptor (called WebObjects adaptor or sometimes HTTP
adaptor) routes client requests processed by an HTTP server to WebObjects
applications and returns the response to the server, which sends it back to the
client. WebObjects makes available several adaptors, of which only one can be
active with a particular server at a time. Every transaction with a WebObjects
application uses the currently active adaptor.
However, the relationships between adaptor and application are (potentially)
many-to-many. Multiple instances of the same WebObjects application can run
on the same machine or a variety of machines and communicate with the same
adaptor. In addition, multiple HTTP servers can be running on the same
machine or on different machines; each server can have its own adaptor, each
with its own constellation of application instances. Although there can be only
one active HTTP adaptor per HTTP server, an application can concurrently
communicate with other types of adaptors, such as an adaptor that uses
Distributed Objects or a secure-socket adaptor.
There are two general types of HTTP adaptors:
• The CGI adaptor, an executable file named WebObjects or WebObjects.exe which
resides in the host HTTP server's “cgi-bin” directory. This adaptor is
available on all supported platforms. It is generic in that it works with any
HTTP server conforming to the Common Gateway Interface (CGI).
• API-based adaptors, that is, adaptors based on APIs specific to particular
web server. Three NSAPI adaptors, all based on the Netscape Server API
(2.0, 2.0.1, and 3.0), are available on all supported platforms except Mach. A
WebObjects adaptor based on Microsoft’s Internet Information Server API
(ISAPI) is also supported. The API-based adaptors have a performance
advantage over CGI adaptors in that the associated server can dynamically