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<!DOCTYPE HTML PUBLIC "html.dtd"><HTML><HEAD><TITLE>Presenting XML:Automating the Web: Rapid Integration with XML:EarthWeb Inc.-</TITLE><META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW"><SCRIPT><!--function displayWindow(url, width, height) { var Win = window.open(url,"displayWindow",'width=' + width +',height=' + height + ',resizable=1,scrollbars=yes');}//--></SCRIPT></HEAD><BODY BGCOLOR="#FFFFFF" VLINK="#DD0000" TEXT="#000000" LINK="#DD0000" ALINK="#FF0000"><TD WIDTH="540" VALIGN="TOP"><!-- <CENTER><TABLE><TR><TD><FORM METHOD="GET" ACTION="http://search.itknowledge.com/excite/cgi-bin/AT-foldocsearch.cgi"><INPUT NAME="search" SIZE="20" VALUE=""><BR><CENTER><INPUT NAME="searchButton" TYPE="submit" VALUE="Glossary Search"></CENTER><INPUT NAME="source" TYPE="hidden" VALUE="local" CHECKED> <INPUT NAME="bltext" TYPE="hidden" VALUE="Back to Search"><INPUT NAME="sp" TYPE="hidden" VALUE="sp"></FORM></TD><TD><IMG SRC="http://www.itknowledge.com/images/dotclear.gif" WIDTH="15" HEIGHT="1"></TD><TD><FORM METHOD="POST" ACTION="http://search.itknowledge.com/excite/cgi-bin/AT-subscriptionsearch.cgi"><INPUT NAME="search" SIZE="20" VALUE=""><BR><CENTER><INPUT NAME="searchButton" TYPE="submit" VALUE=" Book Search "></CENTER><INPUT NAME="source" TYPE="hidden" VALUE="local" CHECKED> <INPUT NAME="backlink" TYPE="hidden" VALUE="http://search.itknowledge.com:80/excite/AT-subscriptionquery.html"><INPUT NAME="bltext" TYPE="hidden" VALUE="Back to Search"><INPUT NAME="sp" TYPE="hidden" VALUE="sp"></FORM></TD></TR></TABLE></CENTER> --><!-- ISBN=1575213346 //--><!-- TITLE=Presenting XML//--><!-- AUTHOR=Richard Light//--><!-- PUBLISHER=Macmillan Computer Publishing//--><!-- IMPRINT=Sams//--><!-- CHAPTER=15 //--><!-- PAGES=0283-0300 //--><!-- UNASSIGNED1 //--><!-- UNASSIGNED2 //--><P><CENTER><A HREF="../ch14/0280-0282.html">Previous</A> | <A HREF="../ewtoc.html">Table of Contents</A> | <A HREF="0287-0289.html">Next</A></CENTER></P><A NAME="PAGENUM-283"><P>Page 283</P></A><H3><A NAME="ch15_ 1">CHAPTER 15</A></H3><H2>Automating the Web:<BR> Rapid Integration <BR>with XML</H2><B>by Charles Allen</B><P>This chapter explores the use of XML to provide apractical and cost-effective means for diverse business systems tobe rapidly integrated across corporate intranets, extranets,and the Internet. The following topics are covered:</P><UL><LI> The transformation of the Web from anaccess medium into an integration platform<LI> Applets, plug-ins, agents, and channels<LI> Dynamic HTML and the Document ObjectModel (DOM)<LI> Electronic commerce<LI> XML as an integration platform</UL><A NAME="PAGENUM-284"><P>Page 284</P></A><H3><A NAME="ch15_ 2">Weaving the Web</A></H3><P>The emergence of XML promises to accelerate the evolution of the Webfrom an access medium to an integration platform, and from a medium foruniversal clients that allows end-users to interact with distributed systems to aplatform for applications that can share and process data.</P><P>Indeed, the ultimate benefit of using Web technologies will be theintegration of an organization's information systems with those of its suppliers,distributors, and customers.</P><P>The delivery of Web data in XML documents ultimately will make theWeb more digestible; using XML metadata to describe and add structure toHTML-based Web content enables users to achieve much of this vision today.</P><P>Web integration is a broad topic because the Web is a big place. To helpyou get your bearings, I will lightly sketch the major features of the landscapebefore honing in on the most pertinent details.</P><H4><A NAME="ch15_ 3">Accessing the Web</A></H4><P>The success of the Web has exposed the advantages of distributedinformation systems to a global audience. Access to an Internet terminal is practicallyaccess to the world; national and organizational boundaries now can becrossed with such ease that they often go unnoticed.</P><P>At its beginning, Web content was mostly static; HTML documentswere delivered to browsers directly from the Web server's file system. Today,Web sites with dynamic content are appearing at an astonishing rate.Relational databases integrated with Web servers are responsive to user selections,transforming standard database queries into result sets presented as HTML <BR>documents.</P><P>Transactional applications, such as mainframe-based order processingand banking systems, are also being connected to Web servers to give usersreal-time data in HTML formats.</P><P>The use of standard formats and protocols to provide access to corporateinformation and documentation has transformed both how organizationsare perceived and the way that organizations knit themselves together. In theprocess, the Web browser has morphed from an occasionally informativeaccessory into an essential platform for organizations of all sizes and shapes.</P><A NAME="PAGENUM-285"><P>Page 285</P></A><P>There is no doubt that ubiquitous access promises to increase productivityon some fronts; at the same time, however, the Web's almost exclusive focuson end-users threatens to reinforce manual inefficiencies in business processes.</P><P>It is common, for instance, for users to transcribe data from Webbrowser windows into existing corporate applications, especially when the Web datais coming from remote business units or external organizations. The rapidspread of dynamic Web data thus threatens to spawn armies of clerical clickers.</P><P>Web servers today serve data to countless browsers; the goal in automatingthe Web is to have them serve data, or functions, to diverse applications. Inother words, Web servers should be accessible as middle-tier application servers.</P><H4><A NAME="ch15_ 4">Serving the Web</A></H4><P>The proliferation of database and transaction-based applications on theWeb necessarily implies a proliferation of software platforms that connectcorporate data sources to the infrastructure of the Web. Approaching the subjectof practical Web integration over standard Web protocols, don't limityourself to the more enlightened publishers who rapidly adopt XML as a meansof preserving structure in Web data.</P><P>The only technologies you can count on Web server platforms to share inthe near term are HTTP, HTML, and SSL. The use of XML metadata todefine functional services over these standard protocols will enable developers toexploit this common ground.</P><P>As you are now well aware, HTML was designed for presentation, notexchange, of information. It is only natural that proprietary workarounds toHTML's limitations have appeared at several stages in the process of deliveringcontent to end-users.</P><P>On the server side, products have appeared that interpret proprietary tagsor HTML extensions at runtime. Such extensions enable richer contentmanagement frameworks, providing templates for the conversion of heritage andrelational data into HTML documents, and for the application ofadvanced formatting and styles. This technology is contributing directly to theappearance of mountains of mission-critical data on the Web.</P><P>The benefits of server-side HTML extensions are primarily in flexiblesite management and rapid deployment. The costs are that valuable detail islost in the process of merging templates with business data into standardHTML documents, and that a greater burden is placed on servers.</P><A NAME="PAGENUM-286"><P>Page 286</P></A><P>Database Read/Write and Transaction-Based Browser applications thatutilize HTML lose detail regardless of their server-side implementation.</P><P>In the long run, XML will help in all of these areas. Today, however, themost sophisticated Web server platforms must still cater to a browser-basedaudience that is dependent on HTML. The result is that Web content creatorsre primarily concerned with formatting, not data structure.</P><P>The following product price list, for instance, has lost importantinformation about the names and relationships of the database tables where the data <BR>originated:</P><!-- CODE //--><PRE> <TABLE> <TR><TD>Hammer </TD><TD>12.00</TD><TD>50</TD><TD>Tom's Tools </TD></TR> <TR><TD>Screwdriver</TD><TD>8.00 </TD><TD>60</TD><TD>Handyman Hardware</TD></TR> <TR><TD>Pliers </TD><TD>10.00</TD><TD>35</TD><TD>Get A Grip! </TD></TR> </TABLE></PRE><!-- END CODE //--><P>To establish a functional relationship between a non-browser client andthe data that is contained within such HTML, it is necessary to reintroducestructure via metadata files that map specific elements of the document to fieldnames or program variables.</P><P>Not much is gained if the burden of providing such metadatais laid at the door of content providers. The architecture must be flexible enough toenable any organization to provide the metadata necessary to automateinteractions with the resources provided by any other organization's Web servers.</P><P>Before discussing exactly how this can be accomplished, I want to explorea little further the challenges presented by the technology of the Web today.</P><H4><A NAME="ch15_ 5">The Desktop Dilemma</A></H4><P>I have discussed how proprietary server-side extensions have attempted toaddress some of the shortcomings of the Web. On the client side, plug-ins,Java applets, and ActiveX are playing a similar role by enabling importantfunctionality at the expense of introducing proprietary data formats that limit eithercross-platform deployment or the capability of other applications to processWeb content.</P><P>Delivering client applications dynamically over the Web seems to solve manyof the most troubling deployment issues introduced by client/serverarchitectures.</P><P><CENTER><A HREF="../ch14/0280-0282.html">Previous</A> | <A HREF="../ewtoc.html">Table of Contents</A> | <A HREF="0287-0289.html">Next</A></CENTER></P></TD></TR></TABLE></BODY></HTML>⌨️ 快捷键说明
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