World-Wide Web (WWW) is a network within the Internet consisting of servers that provide information in hypertext format and clients that relay input from the user to the server and display information on the servers in the format specified by the user. While the FTP server and Gopher server present information in a hierarchical directory structure, WWW information is presented in pages. A page can be an index or a document. Pages have hypertext entries, like those in Windows Help files, that are linked to other WWW pages; a link can refer to a page on any of the thousands of WWW servers. A link can also connect to other kinds of Internet resources. Users access information, or navigate through the Internet, by selecting highlighted words in the documents, including indexes, that are shared on WWW servers.
The commands used by the WWW are defined in the HyperText Transfer Protocol (HTTP). Mosaic is a commonly used client software application for use on the WWW. Often the terms "World-Wide Web," "HTTP," and "Mosaic" are used interchangeably. For example, the filename for the WWW server in this resource kit is HTTPS.EXE for HTTP Server.
To specify the location of a resource, HTTP uses Uniform Resource Locators (URLs), which follow a naming convention that uniquely identifies the location of a computer, directory, or file on the Internet. The URL also specifies the Internet protocol (Gopher, HTTP, etc.) needed to retrieve the resource. If you know the URL of a resource, you can locate it directly, or you can link to it in a document you make available to WWW users.
The advantage of using WWW is that it makes it easy for Internet users to find and retrieve the information you have made available to them. However, publishing information via WWW involves more than just sharing files, since WWW uses hypertext. You must format your files to conform to the HyperText Markup Language (HTML), which is the standard format of the WWW. HTML authoring tools are available to make this job easier and are described later in this chapter.
The HTTP Server service currently does not do logon authentication, while the FTP Server service does. This means that the WWW server can handle a greater load because it isn't doing verification for each user. It also means that the information you share through WWW is available to everyone using the Internet.
For your Windows NT computer to act as a server on the World-Wide Web, you must install the Windows NT HTTP Server service, which is included with this resource kit.
The EMWAC document, HTTP Server Manual, is included in this resource kit and gives you complete information on installing and configuring the HTTP Server service. It is in the same directory with the files for the HTTP Server program (HTTPS.*).
The HTTP Server service is started, stopped, and paused through the Services option in Control Panel, like any other Windows NT service. Errors are logged to an Event Log and can be viewed with the Event Viewer. In addition, you can log all HTTP requests that the server receives by marking the Log HTTP Transactions checkbox in the HTTP Server Configuration dialog.
You can also have the HTTP Server search WAIS databases and return the results to the World-Wide Web user in the form of an HTML document. For more information on this feature, see the EMWAC document, HTTP Server Manual. This document also tells you how to create scripts and forms for use by World-Wide Web users.
A page in the WWW is an ASCII text file that contains formatting commands that conform to the HyperText Markup Language (HTML). HTML files are transferred in plain ASCII over the Internet, and then the client software interprets the embedded formatting commands and displays the file, using fonts and colors as specified by the client user.
The formatting commands appear as markers in the text file. For example, to make text appear bold, you would surround it with the markers <B> to begin bolding and </B> to end bolding, like this: <B>Bold text</B>. Heading styles, fill-in forms, pictures, and hypertext all have their own markers, and are used to supply links to bookmark markers elsewhere in the same document or to other documents on the Web. The user does not normally see the markers, just their effects. Some WWW browsers let you to see the document source, with codes, which lets you see for yourself how a document is formatted.
There are many HTML authoring tools available on the Internet, freeware and shareware. Some of these are text-based, with menu items that let you add markup codes to highlighted text. Some are add-ons to Microsoft Word or Microsoft Word for Windows that let you author documents in Word using a provided template, producing an HTML file instead of a Word file. There are also many conversion utilities, for example one to convert .RTF (Rich Text Format) files to HTML files. Some examples of these programs, and the locations where they might be found, are shown in the following table.
Note Names on the Internet are case-sensitive; if a letter is capitalized in the directory name you should capitalize it when specifying the directory.
Table 21.3 HTML Authoring Tools Available on the Internet
Application | Site | Directory | File name |
HotMetaL | ftp.ncsa.uiuc.edu | Web\html\hotmetal\Windows | hotmetal.exe |
HTML Writer | diable.upc.es | pub\software\www\html | htmlwrit.zip |
HTML Assistant1 | ftp.cs.dal.ca | htmlasst | htmlasst.zip |
HTMLed | pringle.mta.ca | pub\HTMLed | htmed11.zip |
HTML Hyperedit | info.curtin.edu.au | pub\internet\windows\hyperedit | htmledit.zip |
ANT-HTML2 (Word 6.0 templ.) | ftp.einet.net | einet\pc | ant_html.zip |
CU-HTML | ftp.cuhk.hk | pub\www\windows\util | cu_html.zip |
GT-HTML | ftp.ncsa.uiuc.edu | Web\html\hotmetal\Windows | gt_html.zip |
TagWiz | ftp.cica.indiana.edu | pub\pc\win3\winword | html.zip |
1 HTML Assistant is freeware for non-commercial purposes.
2 ANT-HTML is shareware
For instructions on using HTML, access the following file through the Internet:
http://www.ncsa.uiuc.edu/General/Internet/WWW/HTMLPrimer.htmlThe file is itself an HTML document, as well as a primer on using HTML.
The links in HTML documents point to a specific marker, or to the URL for a specific directory or file. It sometimes happens that, after an HTML document has been posted, a file or directory that it points to is removed, or the name is changed. When this happens, the link ceases to work. A user who finds a failed link is likely to contact the author directly to find out where the resource is, and to report the failure of the link.
Of course, you should always test the links in your HTML documents before making them available. A simple typographical error can cause a link to fail.
If you are trying to track down a lost link (one that used to work but now fails), and you know the owner of the page you were linking to, you can contact the owner and ask for the new URL for the page. If you do not know the author, you might be able to find the page by browsing directories near the last known source. (A file might have been moved from a subdirectory to a parent directory, for example, or new subdirectories might have been created to better organize a growing collection of files.) If you cannot find the page, you need to edit the HTML file to remove the link. Check the text of the document to make sure that it does not lead the reader to expect a link at that point.
Once you make resources available on the WWW, people can start linking to them in their own HTML pages. This means that moving or renaming a resource after it has been shared can cause links to fail in other pages throughout the web, and bring you an avalanche of mail and phone calls asking for the new URL. Plan carefully when naming and organizing the resources you want to share.