AOLserver America Online’s open source webserver

1. AOLserverAmerica Online’sopen source webserver Dossy Shiobara February 2005

2. About Dossy Shiobara • I've been using AOLserver since late 1999 to serve my own personal websites, as well as helping to support others who use it. • In 2003, I joined AOL where I support the sites at AOL that use AOLserver as well. • I'm currently the Project Leader of the AOLserver project. • I’m the initial developer of two AOLserver modules, nsmysql and nsfreetds. I’ve also contributed to the core server, as well as nsopenssl and other modules.

3. A brief history of AOLserver

4. NaviSoft (before Nov 1994) • Company started by producing high-quality client- and server-side tools for web publishing: NaviPress and NaviServer. • NaviPress was one of the first WYSIWYG HTML editors. • NaviPress could send changes up to NaviServer (using HTTP PUT) making web site management and updating simple. • Because of this capability, NaviPress/NaviServer was one of the first entrants into the distributed web authoring space. • NaviServer was designed to be multi-threaded from the beginning. (In comparison, multi-threaded Apache was only declared GA or “General Availability” or non-beta in Apache 2.0.35 in April 2002.)

5. AOL (after Dec 1994) • In 1994, AOL realizes the need to enter into the Internet and World Wide Web space. • AOL acquires NaviSoft, Inc. on November 30, 1994. • NaviServer is renamed AOLserver, NaviPress to AOLpress. • AOL offers commercial web hosting through NaviService, then GNN Hosting, then PrimeHost, using AOLserver/AOLpress. • AOL launches Digital City, Inc. (DCI) in 1996 on AOLserver platform. Continues to use AOLserver for other web properties over the years (Moviefone.com, Mapquest.com, etc.). • AOLserver 3.0 released as open source on July 8, 1999. • AOLserver 4.0 released in November, 2003

6. So, what is AOLserver?

7. What can I do with AOLserver? • Run a server with high quality code resulting in very few security vulnerabilities found in the wild. • Easily administrate your servers through configuration files that are programs themselves. • Rapidly develop applications using a mix of C and Tcl that leverage a scalable, multi-threaded architecture. • Serve existing CGI (using nscgi), PHP (using PHP’s AOLserver SAPI module), and JSP/Java Servlets (using Tomcat and nsjk2).

8. What can’t I do with AOLserver? • Not suited for hosting different customers within the same server process because of multi-threaded nature. Each customer needs their own server process. • Not many off-the shelf applications available to download, install and run. • No support for mod_perl at the moment.

9. Who uses AOLserver? • Commercially: • America Online: AOL.com, Moviefone.com, Mapquest.com, etc. • KnowNow’s LiveServer • Educational/Academic: • dotLRN (.LRN) – distance e-learning (MIT Sloan School of Business, etc.) • SMLserver – Standard ML ’97 (IT University of Copenhagen) • Others: • ArsDigita Community System (ACS) • OpenACS – community site toolkit (Greenpeace, Creative Commons, etc.)

10. How do I get AOLserver? • AOLserver is freely available, open source software, hosted at SourceForge. • AOLserver is approximately 75K lines of C code and 5K lines of Tcl code. • AOLserver project website is at http://aolserver.com/. • Site contains download links of source tarballs, links to the AOLserver Wiki, and other documentation links. • For more information on Tcl, go to http://www.tcl.tk/.

11. Examples

12. Server configuration • The server configuration is just another Tcl script that gets executed at server start-up. • Example “nssock” (HTTP listener) module configuration snippet: ns_section “ns/server/${servername}/modules” ns_param nssock nssock.so ns_section “ns/server/${servername}/module/nssock” ns_param port 80 ns_param hostname www.example.com ns_param address 192.168.0.1

13. AOLserver Dynamic Pages (ADPs) Source: <% set now [clock seconds] ns_adp_puts “It is now $now, or [clock format $now].” %> Output: It is now 1109047145, or Mon Feb 21 11:39:05 PM EST 2005.

14. Another way of doing it Source: <% set now [clock seconds] %> It is now <%= $now %>, or <%= [clock format $now] %>. Output: It is now 1109047145, or Mon Feb 21 11:39:05 PM EST 2005.

15. Servlet-like request handling Bind a Tcl proc to handle requests for a particular URL: ns_register_proc GET /demo/time getTime proc getTime {} { set now [clock seconds] set page “<html><body>\n” append page “It is now $now, or [clock format $now].\n” append page “</body></html>\n” ns_return 200 text/html $page }

16. Query a SQL database Query a SQL database to build up part of an HTML page: set page “<html><body>\n” set db [ns_db gethandle userdb] set row [ns_db select$db “SELECT username FROM users”] while {[ns_db getrow$db $row]} { append page “User: [ns_set get $row username]<br/>\n” } append page “</body></html>\n” ns_set free $row ns_db releasehandle$db

17. Perform a task in a background thread Perform a task in a background thread: ns_schedule_proc 3600 hourlyCheck proc hourlyCheck {} { set errors [… collect errors from log file …] if {[string length $errors]} { ns_sendmail errors@mydomain.com \ aolserver@mydomain.com \ “Errors Encountered” $errors } }

18. Summary

19. AOLserver … • was originally named NaviServer when first created in 1994. • is an open source webserver available from SourceForge. • is mostly written in C, approximately 75K LOC today. • uses Tcl as its embedded scripting language, another 5K LOC. • has employed a multi-threaded design from the start. • is suitable for rapidly developing fast, scalable, dynamic and data-driven web applications. • has been proven stable and capable over the years through aggressive use in some of the world’s busiest websites at AOL. • has been ported to many platforms: Solaris, Linux, Win32, MacOS X, BSD, Irix, HP-UX, etc.

20. Questions? Comments?