ASF, Apache Software Foundation provides support for the Apache community of open-source software projects ASF members -- board of directors -- ASF Licence membership: invitation only (meritocracy) Apache project(s) collaborative, consensus based development process Open source-project discloses source code for inspection and/or modification NCSA web server maintained by the Development Group of the National Center for Super-computing Applications first generation server -- limited configuration slots Apache HTTP Server VERY stable and flexible HTTP daemon for many platforms was rewrite of NCSA server (very buggy) -- a patch-y server -- urban legend? Books written about the Apache HTTP Server Apache HTTP Test Project designing test tools for the Apache Flood - a profile-driven HTTP load tester -- a perl-centric HTTP test kit -- modules for SPECWeb99 tests libapreq - Generic Apache Request Library modules for manipulating client request data via the Apache API with Perl and C parsing of application/x-www-form-urlencoded data, multipart/form-data, HTTP cookies Apache HTTP Server, Version 1.3.x proven HTTP daemon -- multiplatform -- very flexible -- modular -- most popular since years Hypertext Transfer Protocol -- HTTP/1.1 protocol specification from W3C resource pooling memory allocation in handled via a pool manager -- not through OS can be optimized generic module support Apache modules may now be loaded at runtime virtual hosting hosting of web sites without additional IP addresses -- useful for ISPs Windows Operating System best operating system in the world (according to Microsoft) Windows NT, 95, 98, 2000, XP, ... Unix operating system too hard for my mum OS/2 operating system IBM Apache HTTP Server, Version 2.0.x Unix Threading Unix POSIX threads support -- Apache can now run in a hybrid multiprocess, multithreaded mode -- should improve scalability Multiprotocol Support infrastructure to support serving multiple protocols Apache API 2.0 module ordering is now done per-hook to allow more flexibility -- new calls additional module capabilities without patching the core Apache server IPv6 Support on systems with APR support Module Filtering modules may now be written as filters -- act on the stream of content Apache Portable Runtime (APR) free C library, a system portability layer to many operating system faster and more stable code on non-Unix platforms such as BeOS, OS/2, and Windows Jakarta Project server application infrastructure based on Java Alexandria Project CVS/Javadoc/Source code/Documentation management system -- global documentation and source organization system Ant 'make' for Java Cactus Cactus is a simple test framework for unit testing server-side java code (Servlets, EJBs, Tag Libs, Filters, ...) Jetspeed Enterprise Information Portal, using Java and XML syndication -- Portal Structure Markup Language -- Portlets Jakarta Taglibs JSP custom taglib kit -- custom tags help separate presentation from implementation -- The Apache/Perl Integration Project Perl interpreter for Apache -- access for Perl modules to Apache -- persistent Perl data apache php integration project is actually original PHP project Apache Tcl Project Tcl as an HTML-embedded scripting language, similar to PHP -- mod_tcl -- Rivet Apache XML Project open XML infrastructure -- XML parser, stylesheet processor, SOAP, SVG Xerces Java, C++ parser with Perl and COM bindings validating parser, DOM1, DOM2, SAX2 standard Xalan, XSL stylesheet processors Java, C++ (alpha) Cocoon: XML-based web publishing separation of logic, content, design -- sitemaps, generators, transformators, serializers, pipelines Java servlet doing transformations as configured FOP: XSL Formatting Object processor written in Java, org.apache.fop converts FO code into various formats (PDF, SVG, ...) Xang server-side XML, DOM and JavaScript (ECMAScript) Apache SOAP IBM contributed SOAP4J implementation Jakarta Tomcat Tomcat is the official Reference Implementation for the Java Servlet and JavaServer Pages technologies Lucene written in Java full-text retrieval, indexing and search capability Apache Architecture http engine, module infrastructure, phases preforking children children a create BEFORE requests arrive static or adaptive to load Apache component Apache is built in a modular fashion, performance, flexibility Apache Core Core Apache features basic server functionality, utility functions (allocation) -- HTTP engine -- main loop -- request dispatching to modules -- basic configuration management Apache module module handlers are activated in particular phases -- sequence of activation matters -- expose same interface to server: configuration handlers, phase handlers the most popular come with the distribution many more by 3rd parties (e.g. mod_frontpage) do not usually fork new processes (except mod_cgi) Apache contributed module come with the distribution Apache 3rd party modules Apache HTTP request request is stored in a request record ($r in Perl) -- applications and modules have access Apache request phase every client request is serviced in phases URI translation translation from URI to file system (backend name space) Access check based on host name, et. al. User authentication who is this user? User authorization can this user access a resource? MIME detection what is the MIME type of the requested resource? Fixup resolving aliases... Event logging log the request depending on the configuration Module handler will be activated by Apache in one of the phases -- modules define handlers -- several handlers per phase -- sequence matters -- usually written in C -- Perl Apache handler mod_env Passing of environments to CGI scripts mod_setenvif Set environment variables based on client information mod_unique_id useful in a web cluster -- clocks synchronized -- hostnames differ generate unique request identifier for every request -- magic token -- even unique across multiple machines in a cluster mod_mime Apache module determine various bits of "meta information" about documents -- file extensions AddLanguage en .en AddEncoding x-gzip .gz AddHandler cgi-script .cgi AddType image/gif .gif files with multiple extensions: welcome.fr.html mod_mime_magic determining document types using "magic numbers mod_access Apache module Access control based on client hostname or IP address Allow from 10.1.2.3 -- Deny from all relative to a directory or location mod_alias Apache module Mapping different parts of the host filesystem in the document tree -- URL redirection Alias /image /ftp/pub/image mod_auth Apache module trivial user authentication -- basic authentication -- text database AuthType Basic -- AuthName MyPrivateFile -- Require valid-user