AOLserver is the open-source Web server of America Online, the Internet provider with the most clients in the world. AOL uses AOLserver as a Web server for one of the highest traffic environments on the Internet.
AOLserver is a server HTTP type multithreaded, based on TCL, which includes much ease of use – oriented large – scale environments and sites Web with dynamic content.
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History Of AOLserver
AOLserver server pages is a Web that was developed in 1994 by Jim Davidson and Doug McKee two creators of Unix in Santa Barbara as part of a publishing system Web.
The first part of the system was NaviPress, a web page editor of type what you see is what you get (WYSIWYG, what you see is what you get).
NaviSoft wanted to allow untrained people to maintain Websites, not just Web pages. So they produced their own Web NaviServer, which would not only respond to the standard GET and POST methods but also to the PUT method.
This method allows the user to send a page to the Web server for them to place on their file system. This feature was innovative enough to help AOLserver win each magazine’s “Best Web Product” award in early 1995.
America Online company bought NaviSoft, and now the source code is free and published by AOL company.
AOLserver is distributed under the AOLserver Public License, which is similar to that of Mozilla ( Mozilla Public License).
AOLserver Characteristics
Access Control
AOLserver’s access control system allows you to define users, assign users to groups, and configure permissions for users, groups, etc. The intention of this system is to allow the highest possible atomicity when handling permissions while allowing general changes to be made.
When defining permissions for AOLserver, you can specify the lists of allowed or disallowed users and the lists of allowed or disallowed groups.
Multiple Servers
AOLserver allows you to run multiple servers on one machine by linking them to different combinations of ports and/or IP addresses. The goal of this approach is to provide not only users but also administrators with more than one different way to access the same machine; This is done with the intention of allowing a single machine to respond to requests made to more than a single IP address.
Database Service
AOLserver handles groups of open connections to databases. These groups allow AOLserver to quickly serve concurrent requests to databases, without continually opening and closing the database. The APIs of TCL and C provide access to these databases groups.
Programming Interface
TCL Interface
AOLserver can be extended using the TCL scripting language . It provides a powerful TCL API that contains a complete array of functions and primitives that give developers access to all the functionality of AOLserver and SQL databases.
TCL functions are available to interact with the connection, implementing scheduled procedures, interface threads, access to databases, among others. The programmer can create scripts in a private TCL library for each server, or in a shared library for multiple servers.
AOLserver Dynamic Pages (ADPs)
The ADPs allow you to fit scripts (sequences of instructions) TCL directly inside pages HTML. The script, or scripts being more than one, are dynamically interpreted when the page is accessed.
C Interface
AOLserver can also be extended with an API for the C language . The API for C allows the programmer to write their own log routines, access control system, communication handlers, or database handlers. It provides all the necessary functions and structures you need to access all the functionality of AOLserver and databases.
To use the API in C, the programmer compiles its C module into a shared Unix library. AOLserver will dynamically load the module and call its launch function.
CGI Support
AOLserver provides complete CGI support. Running a CGI program is less efficient than extending AOLserver with TCL or C because it requires a separate process to be created. The programmer can configure AOLserver to search for CGI programs in a specific directory, or store CGI programs within HTML files and refer to them using the .cgi file type.
Any file with a .cgi extension should be interpreted as a CGI program by AOLserver. AOLserver can be configured to enable file types with a .cgi extension in specific directories or in directory groups.
Advantages Of AOLserver
Open ACS
One of the main reasons you can make the decision to use AOLserver is Open ACS, which offers a series of Open-Source applications with a focus on community users.
ADP (“Aol Dynamic Pages”)
ADP (AOL Dynamic Server Pages) have the same operation as ASP (Active Server Pages) or JSP (Java Server Pages), a page written in HTML that contains fragments of a programming language, in the case of ASP the VBScript language is used and JSP is used Java, while ADP of AOLserver uses TCL (Tool Command Language).
Internal Interpreter for “Scripts”
One of the advantages that AOLserver has is that it includes a TCL interpreter embedded in its structure, due to this it is possible to keep Scripts in TCL that will be executed internally. AOLserver has support for CGI, but due to the superior execution of (internal) Scripts in TCL, the use of CGI with Perl is of little use.
Access to Database
AOLserver maintains pools of latent Pools connections to databases, these Pools connections allow AOLserver to perform faster searches (there is no need to continuously open and close the connection to the Database).
TCL API and C API
Since AOLserver is written in TCL, it provides several functions in the TCL API, some of which allow: interacting with the HTTP connection, maintaining URL permissions, accessing databases, among others. AOLserver also provides an API in C, in case it is required to write a special module that performs access control, communication drivers or other functionalities.
