introduction to web technologies for effective ... · introduction to web technologies for...

Introduction to Web Technologies for Effective Dissemination

of Information

13 November 2000SIGAda 2000

Mr. Currie ColketSIGAda Vice Chair for Meetings and Conferences

Phone: (703) 883-7381; Email: [email protected] | [email protected]

Dr. John McCormickSIGAda Secretary


Mr. David A. WheelerInstitute for Defense Analyses


Mr. Clyde RobyInstitute for Defense Analyses

Phone: (703) 845-6666; Email: [email protected]

SIGAda Home Page Íhttp://www.acm.org/sigada

13 November 2000 SIGAda WWW 2

© Currie Colket, Brad Balfour, John McCormick, Clyde Roby, & David Wheeler for ACM SIGAda

Motivation

This tutorial is designed for the SIGAda volunteer interested in using WWW technologies to promote Local activities and Working Group activities. At the end of this tutorial, you will be able to:

• Use simple web-authoring tools• Develop your own Home Page• Tailor it to effectively communicate to your audience• Establish Home Page on ACM host• Use simple web-posting tools• Use simple web-verification tools• Establish maillists for your activity



Overview• Introduction to WWW and SIGAda Home Page as Notional Example

(John McCormick ~ 20 minutes)

• Introduction to HTML and use of Netscape Composer (Currie Colket ~ 90 minutes)

• Effective Design Strategies Appropriate to Disseminating Information(Clyde Roby ~ 30 minutes)

• Tools to Manage Development of Web Pages(Clyde Roby ~ 40 minutes)

• Introduction to Ada CGI (David A. Wheeler ~ 90 minutes)

• Using ACM WWW and Maillist Facilities (John McCormick ~ 60 minutes)

• Introduction to XML (Currie Colket ~ 30 minutes)

Start: 8:30Break: 10:00Lunch: 12:00Back: 1:30Break: 3:00End: 5:00



Introduction to SIGAda Home Pageas Notional Example

John McCormickSIGAda Secretary



SIGAda Home Page - 1



Introduction to HTML and use of Netscape Composer

Currie ColketMITRE

SIGAda Vice Chair for

Meetings and Conferences



Introduction to HTML• HTML Basics• Fonts; Colors; Bold; Italics• Creating Lists• Creating Links to URLs• Creating Anchors/Targets• Creating Relative Links• Creating Mailto Links• Incorporating Images• Putting Code On-line• Forms • Using the HTML <Head>• Netscape Composer (a WYSIWYG)• Creating Tables



Motivation for Knowing HTMLMany WYSIWYG Tools- Why Learn HTML?

• Output of tools is not always portable• Some use advanced features of HTML• Some use non-standard extensions of HTML• Some tools generate XML instead of HTML

• Browsers typically omit information not understood• Many browsers can’t handle XML• Tools can not always support desired goals• Occasionally cleanup of HTML code is required

• Porting from one tool to another• Eliminate garbage automatically generated

• Strengthens understanding of WWW capabilities• Understanding HTML is good foundation for XML



What is HTML• Lingua franca for publishing hypertext on the World Wide Web• Non-proprietary format based upon SGML• Created and processed by a wide range of tools

from simple plain text editors to sophisticated WYSIWYG authoring tools• Uses tags such as <h1> and </h1> to structure text for Presentation• Browsers attempt to produce page even when there are errors• Produced by W3C as recommendation; voted on by Consortium members

http://www.w3.org/MarkUp/• Status: Version 4.01 is current recommendation, replacing Version 3.2

• Support for Style Sheets - Control color, font, and layout• Internationalization Features - text right to left (Hebrew & Arabic)• Accessibility Features - Braille and speech synthesizers• Tables and Forms - many new features• Scripting and Multimedia - many new features

• 3 Flavors of HTML:• Transitional - take some advantage of 4.0, but primarily support 3.2• Strict - use style sheets, i.e., free of tags associated with layout• Frameset - used to partition browser into one or more frames

HTML Basics

HTML: HyperText Markup Language is Semantic Markup

physical: indent 1.0”, Use 24-Point Roman Font, Print “Hello”

semantic: <H1>Hello</H1> uses markup tags• Physical is WYSIWYG; HTML will differ on each system• Designed to be extensible, in fact, still evolving• Uses HyperText Transport Protocol (HTTP)• Tag names are case insensitive• HTML Program Structure:

<HTML><HEAD>

<Title>

</heaD><Body>

</BODY>

</HTML>

• Some Tags have attributes

• Text is continuous regardless of spaces/CR

• Most Tags in pairs; solo:<P> Paragraph Break<Br> Line Break<HR> Horizontal Rule

<BODY BACKGROUND=“my_file.jpg” T EXT="#000000" LINK="#0000ff" VLINK="#ff0000" BGCOLOR="#ffffef">



Fonts; Colors; Bold; Italics<H1> Highlighting HTML </H1>

Characters can be highlighted using <B>Boldfaced</B>, <BIG>Big and <BIG>Bigger</BIG></BIG> text, <I>Italicized text</I>, <S>Strike-through Text</S>,<SMALL> Small and <SMALL> Smaller </SMALL> </SMALL> text,with <SUB>Subscripts</SUB> and <SUP>Superscripts</SUP>,with <TT>Typewriter font</TT> and even <U> underlining for emphasis. </U>

<P>There is also a concept of Logical Highlighting using <STRONG>Strongly Emphasized</STRONG> Text,<CODE>Computer Code</CODE> Text,<KBD>Keyboard Character</KBD> Text,<SAMP>Literal Character</SAMP> Text,<DFN>Defining Instance</DFN> Text, <EM>Emphasized</EM> Text,<VAR>Variable</VAR> Text,<STRIKE>Strike-out</STRIKE> Text.

<P><CENTER><FONT COLOR="#009900"><FONT SIZE=+4>SIGAda</FONT></FONT><BR><FONT COLOR="#FF0000"> <FONT SIZE=+3>WWW Tutorial</FONT></FONT><FONT COLOR="BLUE"> <FONT SIZE=+2><P> Sunday, 7:30 - 11:30 PM</FONT></FONT></CENTER>



Creating Lists<H1> List Example </H1>

<P>The 3 most important things in real estate are: [Ordered Lists]<OL><Li> Location,<Li> Location, and </Li><Li> Location (It should be noted that all lists will wrap around with the correct indentation desired for the screen.</OL>

The most important things in talking about software are: [UnOrdered Lists]<UL><Li> Using Bullets Correctly<Li> Using Plenty of Bullets, and<Li> Using Subordinate Bullets When Necessary

<OL TYPE="a"><Li> With Letters<Li> Again with Letters

<OL TYPE="i"><Li> With Small Roman Numerals </OL><OL TYPE="I"><Li> With Large Roman Numerals</OL><OL TYPE="1"><Li> With Numbers </OL><OL TYPE="1" START="7"><Li> Even With Numbers Out of Sequence </OL>

</OL></UL>



Creating Links to URLs - 1<H1> Link Example </H1>

<P>The following URLs contain useful information on using html:<OL><LI> <A HREF="http://www.w3.org/MarkUp/">W3C HTML Home Page</A> -

<I>http://www.w3.org/MarkUp/</I><LI> <A HREF="http://www.w3.org/MarkUp/Activity.html">W3C User Interface Domain</A> -

<I>http://www.w3.org/MarkUp/Activity.html</I><LI> <A HREF="http://www.cc.ukans.edu/~acs/docs/other/HTML_quick.shtml">HTML Quick Reference</A> -

<I>http://www.cc.ukans.edu/~acs/docs/other/HTML_quick.shtml</I><LI> <A HREF="http://werbach.com/barebones/">The Bare Bones Guide to HTML</A> -

<I>http://werbach.com/barebones/</I><LI> <A HREF="http://www.ncsa.uiuc.edu/SDG/Software/Mosaic/Docs/d2-htmlinfo.html">

Creating HTML Documents</A> -<I>http://www.ncsa.uiuc.edu/SDG/Software/Mosaic/Docs/d2-htmlinfo.html</I>

<LI> <A HREF="http://www.eclipse.net/derek/">HTML Primers and Tutorials</A> -<I>http://www.eclipse.net/derek/</I>

<LI> <A HREF="http://www.bbsinc.com/symbol.html">ISO Latin 1 Character Entities and HTML Escape Sequence Table</A> -

<I>http://www.bbsinc.com/symbol.html</I><LI> <A HREF="http://www.willcam.com/cmat/html/crossref.html">Compact Index of HTML Tags</A> -

<I>http://www.willcam.com/cmat/html/crossref.html</I><LI> <A HREF="http://www.ncsa.uiuc.edu/SDG/Software/Mosaic/Docs/d2-tech.html">

HTML, URL, and HTTP Technical Information and Specifications</A> -<I>http://www.ncsa.uiuc.edu/SDG/Software/Mosaic/Docs/d2-tech.html</I>

<LI> <A HREF=”http://dir.yahoo.com/Computers_and_Internet/Information_and_Documentation/Data_Formats/HTML/">Yahoo HTML Search Node</A> -

<I> http://dir.yahoo.com/Computers_and_Internet/Information_and_Documentation/Data_Formats/HTML/ </I></OL>



Creating Links to URLs - 2



Creating Anchors/Targets<HTML><HEAD><TITLE>Anchors/Targets Example</TITLE></HEAD>

<BODY><H1>Anchors/Targets Example</H1><P>Navigation: <A HREF="#Email">Email Addresses</A> | <A HREF="#News">News</A> | <A HREF="#Weather">Weather</A> <Br></P>

<H2><A NAME="Email">Email Addresses</H2><UL><LI><A HREF="email.html">

Pelot Email Addresses</A> </LI><LI><A HREF="email.html#Colket">

Colket Email Addresses</A> <IMG SRC="gif/updated.gif" WIDTH=46 HEIGHT=11></LI>

<LI><A HREF="email.html#Colcord">Colcord Email Addresses</A> </LI>

</UL><H2><A NAME="News">News</H2>News stuff<H2><A NAME="Weather">Weather</H2>Weather Stuff</HTML>



Creating Relative Links

Useful for Program Development

File on local system has same relative name as file on remote system

Switch from one system to other with simple click

<H1><A NAME="Top">Relative Link Example</H1>

<P>Navigation: <A HREF="http://www.colket.org/">

To www.colket.org</A> | <A HREF="file:///c|/www/index.html">

To C Drive</A> <Br>

</P>Technology Resources:

<A HREF="acronyms.html">Acronyms</A> | <A HREF="Ada.html">Ada</A> | <A HREF="confere.html#Conferences_Future">

Conferences</A> | <A HREF="html.html">HTML</A> | <A HREF="internet.html">Internet</A> | <A HREF="java.html#Internet">Java</A> | <A HREF="OO.html#OO">OO</A> | <A HREF="Reuse.html">Reuse</A> | <A HREF="email.html">Email Addresses</A> <Br>



Creating Mailto Links<HTML><HEAD><TITLE>Mailto Example </TITLE></HEAD>

<BODY><H1> Mailto Example </H1>

Please email comments on this course to<A HREF="mailto:

"Currie Colket"<[email protected]>,

"Brad Balfour" <[email protected]>,

"Clyde Roby" <[email protected]>,

"John McCormick" <[email protected]>"

TITLE="Comments on Course">Currie, Brad, Clyde, and John</A>

<P><ADDRESS>Currie Colket <A HREF="mailto:[email protected]"> ([email protected])</A> </ADDRESS></BODY></HTML>

"Currie Colket" <[email protected]>

is equivalent to

“Currie Colket” <[email protected]>



Incorporating Images<H1> Image Example </H1>

<P>ASIS is an interface between an Ada environment as defined by ISO/IEC8652:1995 (the Ada Reference Manual) <IMG Align=bottom SRC="gif/new.gif">and any tool requiringinformation from this environment, as shown below:<IMG SRC="gif/updated.gif" WIDTH=46 HEIGHT=11>

<Center><IMG SRC="gif/asis.gif" ALT="ASIS as interface to Ada compilation environment" WIDTH=488 HEIGHT=306><BR><B>ASIS as interface to Ada compilation environment</B></Center>

Above image made in PowerPoint by:• Creating image; cutting it from page• Using Page Setup, selecting landscape, 3”x5”• Pasting image onto page; aligning it to center• Saving as gif (or jpeg) • Obtaining size using Photo Editor Resize function

Size is important; allows for building page sans images

ALT for browsers without graphicsor browsers turned off

Bad Form

Better Form

Good Form



Putting Code On-line<H1> Code Example </H1>

<P>EXAMPLE: Loop iteration scheme<pre>

List : constant Asis.Element_List := -- 3.7<I><ASIS function returning a list>;</I>

An_Element : Asis.Element; -- 3.6begin

for I in List’Range loopAn_Element := List (I);<STRONG>Process (An_Element);

</STRONG>end loop;</pre>

Use <PRE> for large blocks of code• For Preformatted text• Characters in fixed width• Preserves space characters, CR• Allows for character emphasis• Anchors and text highlighting tags only



Forms - 1<H1> Form Example </H1><FORM ACTION="mailto:[email protected]" METHOD="POST"> <B>Last Name: </B><INPUT TYPE="TEXT" MAXLENGTH="255" NAME="Lastname"><B>First Name: </B><INPUT TYPE="TEXT" MAXLENGTH="255" NAME="Firstname"><Br><B>Address Line 1: </B><INPUT TYPE="TEXT" MAXLENGTH="255" SIZE="50" NAME="Address1"><Br><B>Address Line 2: </B><INPUT TYPE="TEXT" MAXLENGTH="255" SIZE="50" NAME="Address2"><Br><B>City: </B><INPUT TYPE="TEXT" MAXLENGTH="40" NAME="City"><B>State: </B><SELECT NAME="State" >

<OPTION SELECTED> DC<OPTION> MD<OPTION> VA

</SELECT><B>Zip: </B><INPUT TYPE="TEXT" MAXLENGTH="15" NAME="Zip">

<P><B>Area Code: </B><INPUT TYPE="TEXT" MAXLENGTH="3" SIZE="3" NAME="Area_Code"><B>Phone: </B><INPUT TYPE="TEXT" MAXLENGTH="15" NAME="Phone"><B>E-mail: </B><INPUT TYPE="TEXT" MAXLENGTH="80" SIZE="30" NAME="Email">

<P><B>Volunteer Interests:</B>[<INPUT TYPE="checkbox" NAME="Interests" VALUE="Program" CHECKED>Program][<INPUT TYPE="checkbox" NAME="Interests" VALUE="Publicity">Publicity][<INPUT TYPE="checkbox" NAME="Interests" VALUE="Local">Local Arrangements]<SMALL><EM>(Multiple items can be selected.)</EM></SMALL>

<P><B>Ada Awareness Initiative: </B><INPUT TYPE="radio" NAME="Ada_awareness" VALUE="Yes" CHECKED > Yes<INPUT TYPE="radio" NAME="Ada_awareness" VALUE="No" > No<INPUT TYPE="radio" NAME="Ada_awareness" VALUE="Maybe"> Maybe <SMALL><EM>(Only one item can be selected.)</EM></SMALL><Br>

<CENTER><TEXTAREA COLS=60 ROWS=4 WRAP="on" NAME="Special_Notes">Enter any special comments you might have here.</TEXTAREA></CENTER>

<P> <INPUT TYPE="submit" NAME="sub" VALUE="Send Form"> <INPUT TYPE="reset" VALUE="Reset Form">

</FORM>

Action

Text Input

Checkboxes

Radios

Text Areas

Submit/Reset

Text Options



Forms - 2



Forms - 3 <FORM ACTION="mailto:[email protected]" METHOD="POST">

Email = Subject: Form posted from Mozilla Lastname=Colket&Firstname=Currie&Address1=9906+Dale+Ridge+Court&Address2=&City=Vienna&State=VA&Zip=22181-5348&Area_Code=703&Phone=883-7381&Email=colket%40acm.org&Interests=Program&Ada_awareness=Yes&Special_Notes=This+is+a+demonstration+of+posting+forms.+Notice+how+the+text+automatically+wraps+around+as+the+information+is+typed.%0D%0A++&sub=Send+Form

< FORM ACTION ="https://swww.acm.org/signup.cgi" method="post">

Use Ada95 bindings to CGI to automatically process form. • Automatically confirm submission of form• Automatically update database• Perform other analysis of submitted information

David Wheelerwill address

Ada95 Bindings to CGI

Netscape returns as attachment Type: application/x-www-form-urlencodedOthers return in different formats.



Using the HTML <Head>

TITLE (Only required <HEAD> Element)• Used as name for Bookmarks (those >60 are blank)• Used to label display window or text screen• Used by browsers as quick index mechanism

Example: <TITLE> ACM SIGAda Home Page </TITLE>

META (Optional - But highly recommended)• Used for Meta information not explicitly defined elsewhere, Examples:<META NAME=“Keywords” CONTENT= “Ada, Safety-Critical, SE”><META HTTP-EQUIV=“Creation-Date” CONTENT= “17-Oct-99”>

BASE (Optional & NOT Recommended)• Used for recording the base URL of the document• Prevents relative links from developmental environments• Recorded as URL in Bookmarks instead of actual URLExample: <BASE HREF=“http://www.acm.org/SIGAda/index.html” >



Netscape Composer



Creating Tables



Effective Design Strategies

Appropriate to Disseminating Information

Clyde RobyIDA

Note: Originally developed by Brad Balfour of Objective Interface



This Section: Concept and Goals• Main Goal:

– To help understand the many ways that the WWW can be used to communicate information

• Secondary Goal:– To help new “designers” to effectively choose appropriate

techniques from among the many that the web provides

• Technique: Descriptive rather than Prescriptive• Present a series of questions to be asked in order

to decide what structure and techniques to use to build the web pages (web site)

• Also will present a list of “rules” (both the commonly agreed upon and the controversial)



Building A Collection of Web Pages —Things to Think About

• The Audience• Ways the Audience Gets Info and Gets Notified of Changes• Frequency of Browsing by Audience• Why Does the Audience Need Your Site• What Makes the Site Attractive• Kinds of Sites• Types of Information Provided• Organizing the Information• Types of Content• Design Tips/“Rules”



The Audience

•Who are they?•What do they need?•What do they want?•How experienced are they?•What do they already know?•What do they want to find out?•How similar are they to the webmaster?•How different are they from the webmaster?•Are they using modern browsers on fast machines?•Are their graphics enabled?



Ways the Audience Gets Info and Gets Notified of Changes

• Push versus Pull Site Info• Push versus Pull Change Notification

– Interrupt versus Polling– Most web sites are pull only and have no push content

» Not even for notification of changes/updates/new info

• Browsing oriented site info organization• Search oriented site info organization• “Channels”• E-mail notification plus Web-Site• Print “Ads” notification of web-site (or TV)



Frequency of Browsingby Audience

• Multiple Times a Day• Daily• Weekly• Monthly• When Notified• Only when first found

– Or found via a search engine– Or found via a link to the site from the outside

• When ready to purchase• Reference Only (based on external need for info)



Why Does the AudienceNeed Your Site

• Uniqueness?• Timeliness?• Loyalty?• Membership?• Who is your Competition?

– Within SIGAda– Within Ada Community– Within ACM– Within the community of programming languages– With the software development community



What Makes the Site Attractive

• Content?• Look and Feel?• Responsiveness?• Satisfying the Audience’s need?• How much is too much?• How much is too little?• Issues:

– Connection Speed (everyone focuses on this)– Form versus Content (is it “versus”?)– Uniqueness versus Sameness– Freshness of content and form



Kinds of Sites• Informational

– e.g., medicine, academia, most .org

• News– e.g., CNN, MSNBC, ESPN

• Product/Service Oriented (Sales secondary via ads)– e.g., Kelly Blue Book

• Sales/Selling Oriented– e.g., “catalog” ordering, Ford, most product companies

• Organizational - Member Oriented– e.g., info to members only or predominately

• Organizational - Outreach Oriented– e.g., get new members to join based on info



Types of Information Provided(SIGAda specific)

• Technical info• Copies of printed publications• Software (source code and/or executables)• Papers• Data on experiences/results• Membership info• Organizational infrastructure (e.g., meeting minutes,

org. structure, motions, charter, etc)• Historical info (e.g., past e-mail list traffic archive,

conference results)• Contact info• Links to other sites



Organizing the Information• Types:

– Linear– Hierarchy– Graph (DAG)– Random

• Depth of Links• Breadth of Links• What is the relationship between the contents• What do people need to find?

– What do they know when they want to find it?

• Search oriented users versus Browsing users



Types of Content

• Text• Graphics• Multimedia

– Video– Sound

• Stored Documents– Ftp– Served Interactively– (format: PDF, PS, text)

• Software– Source– Executable– Browsed on-line (hyperlinked)– Downloaded

• Steak versus Sizzle• Content versus

Presentation• Competition• General overall Level of

“Professionalism”• Native to the browser

versus needs plug-in• Use of JavaScript• Use of Java• Use of cgi



Design Tips/“Rules”Commonly Agreed Upon

• No blinking text• KISS• Don’t overwhelm with

graphics• Navigate with text instead

of/in addition to any image maps (unless the navigation is truly graphical like a map)

• Make the organization obvious (and help show users where they are at all times)

• Keep links & site up to date

Controversial(like Multiple Inheritance)

• Frames• All sites must be fast to

download– What’s the connection speed

of your users (home versus work)



Tools to Manage Development

of Web Pages

Clyde RobyIDA

[email protected]



Goal and Concepts

• Goal: Development, Management, and Update of a Web Site (many web pages)

• Development and Organization• Management• Updating the Web Site• Fixing the Web Site• Tools to do the Job• An Example: The ASIS Web Site



Web Development

• Local Development of Web Pages• Development of Informational Materials• Moving Your Web Pages to the Web Site



Web Management

• Who Comes to the Web Site?• What do they Visit on the Web Site?• How Often do they Visit/Return?• How do they Retrieve/Use the Information?• Why do they Visit the Web Site?



Updating the Web Site

• Local Update of Web Pages• Updating of Informational Materials• Updating Pages on the Web Site



Fixing the Web Site

• Broken Links• Wrong Information• Outdated Information• ISP Problems• Notification to the Webmaster



WWW Tools

• Tools to Develop the Web Site• Tools to Manage the Web Site• Tools to Update the Web Site• Tools to Find and Fix the Problems



The ASIS Web Site

• ASIS Specification• ASIS Tutorial Pages• Information Updates

– Technical Information– Vendor Product Information

• ASIS Bibliography• Notification to SIGAda-ASIS members• Membership Updates



What This Means

• Test your web site locally• Follow a few simple rules

– Information on Home Page– Links Among Pages on Web Site– ALT for ALL Graphics Images

<IMG SRC=“stuff.gif” ALT=“Description of Stuff”>– Use height and width in graphics– Information and Documents served via links “Save As”– Relatively Short Pages (50K Bytes Max)– For links greater than 50K Bytes, indicate size



Easy Web Site Development• Home Page Information

– Table of Contents– Points of Contact– Becoming Involved

• RELATIVE links– Facilitates development of Web pages– Avoid links with .. Or ../.. (viewed as a security violation)

• Directory Structure “behind the scenes”• Internal links to main/home page and to sponsoring

organization• Proof pages likely to be printed (e.g., maps, program)

– Verify colors are easily readable when printed on black & white– Verify likely page break does not interfere with content use



Page Creation Web Sites

• www.microsoft.com/sitebuilder• members.aol.com/royalef/gifanim.htm• ds.dial.pipex.com/fw/animgifs.htm• www.barebones.com• www.demon.co.uk/Tangent/butwor.html• www.webtechs.com/html-val-svc/• htc.rit.edu/klephacks/markup.html• web.cs.bgsu.edu/morph/morphapplet.html



HTML Editors for Macs

• www.yahoo.com/Computers/World_Wide_Web/HTML_Editors/Macintosh

• www.uwtc.washington.edu/Computing/WWW/Mac/Directory.html

• www.awa.com/nct/software/webtools.html• www.vermeer.com/soft.htm



Mac HTML Editors

• www.navisoft.com/register/client/MP_Trial_1.01.sit.hqx• www.navisoft.com/NS/InsertRow/navipress pre• ftp://bradley.bradley.edu/pub/guru/ps2html/ps2html-v2.html• dragon.acadiau.ca/~giles/HTML_Editor_Documentation.html• sec-look.uiowa.edu/about/projects/arachnid-page.html• ftp://ftp.cray.com/src/WWWstuff/RTF/Users_Guide.html• www.ceneca.com/Ordering.html



General Info for Web Developers

• the-tech.mit.edu:80/KPT/Toms/index.html• linestone.kosone.com/people/nelsonl/nl.htm• www.info.net/~rdralph/icons/symbols/• abs.apple.com/apple-internet/authoring/• the-tech.mit.edu/cgi-bin/KPT_bgs.pl• www.netscape.com/assist/net_sites/bg/backgrounds.html• www.issi.com/people/russ/backgrounds.html• www.primenet.com/~piglett/textures.html• www.designsys.com/champ/background.html• www.sci.kun.nl/thalia/guide/color/faq.html• www.vmedia.com/archives/clipart/index.html

• www.cuteftp.com



Using ACM WWW

and Mailing List Facilities

John McCormickUniversity of Northern Iowa



The SIGAda Home Page

• Is a gateway to a lot of good information for the Ada community

• It is difficult for one volunteer with a full time job to keep all of this information up to date

– Bad links sprout like mushrooms– Lots of old news



Solution - More Volunteers

• We already have– Volunteers from some local SIGAda Chapters – Volunteers from some SIGAda working groups



Local SIGAda Chapters with Web Presence

• Baltimore• Jersey Shore• Twin Cities• Washington, DC



SIGAda Working Groupswith “Recent” Web Presence

• Ada as an HDL WG (forming)• Ada Bindings• ASIS• Commercial Ada Users• Education

– Jobs page (Searching for student worker)

• Safety and Security



More Help Needed in

• Tools, bindings, and components• Ada news• Ada advocacy• Additional locals• Additional working groups



This Tutorial

• Stated agenda– Provide volunteers (including myself) with the basic

information necessary to effectively disseminate information using the world wide web.

• My personal agenda – Recruit volunteers



ACM WWW

• ACM hosts SIG websites– RS/6000 UNIX server– turing.acm.org– Moving to perl.acm.org running Red Hat Linux 6.1

• Home directory for SIGAda is

/acminfo/1/sigs/sigada or/usr2/info/sigs/sigada



Procedures for Setting up a Local or Working Group

Home Page

• Option 1 Set up on your own machine and send me the URL

– Currently used by all locals except DC– Not used by any Working Group

• Option 2 Set up on ACM’s Turing– Currently used by all active working groups



Setting up Pages on Turing

• Requires an account on Turing• I will set up a subdirectory in which to put the

home page• We use UNIX groups and permissions to control

access to SIGAda subdirectories



Getting a Turing Account

• Send me the following information– Name– Company / Institution– Address– Telephone and FAX numbers– e-mail address– ACM membership number– Preferred login name (8 character limit)



Who Can Update a Page?

• Whoever is in the group that owns the file• I welcome suggestions for policy and means of

enforcement.



Guidance for Organizing Files

• Each working group and local chapter on Turing is rooted in their own subdirectory

• All groups currently use a flat organization• There are currently 19 subdirectories in the

SIGAda root directory



Suggestions for Pages

• Link to SIGAda home page• Link to ACM home page• Page owner name with e-mail link

(blank if maintained by SIGAda Secretary)• Date last modified• Should we design templates?



Use of Private Directories with Passwords

• ACM now provides this ability via their member account names

• www.acm.org/infodir/services/access_control.html

• Access control lists set up by ACM support– Based on subscription services or– list individual account names maintained by SIG Information

Director



CGI

• SIGAda used CGI scripts for SIGAda 2000 Conference Registration

• turing.acm.org did not have an Ada compiler available; perl.acm.org does have an Ada compiler

• SIGAda is working with ACM to have the Ada95 cgi interfaces available on perl.acm.org

• ACM policy is that each SIG is on its own



ACM Mailing Lists

• ACM uses Listserv software• Complete documentation at

– http://www.acm.org/infodir/services/listserv/doc.html (links to)– http://www.lsoft.com/manuals/1.8d/index.html:

» LISTSERV List Owner’s Quick Start » LISTSERV List Owner’s Manual » LISTSERV General User’s Guide

• All lists @acm.org– http://www.lsoft.com/SCRIPTS/WL.EXE?XH=ACM.ORG



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Sample List AnnouncementWelcome To The Washington DC SIGAda Chapter Announcements List.

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Introduction to AdaCGI

David A. WheelerIDA



Outline

• Intro: myself, AdaCGI, CGI, Alternatives• Using Ada for Web Apps (+ and -)• High-Level: License, Basics• Using AdaCGI: Minimal Example, Debugging and Installing• Special: Get/Post, Cookies, Security, Recent Additions,

Limitations• AdaCGI spec & Long Example (“Search”)



What is AdaCGI?

• Ada Library implementing the“Common Gateway Interface” (CGI)

– CGI is the most common interface for web-enabled programs (“web apps”)

– CGI is language & platform neutral

• Permits development of cross-platform web-enabled Ada programs

• http://www.dwheeler.com/adacgi



CGI: General Concept (1 of 2)

Web Browser(Client)

Web Server

Web Program/Application

HTTP

CGI

1

(2)

3

4

(5)

6



CGI: General Concept (2 of 2)

• When CGI is used, the following occurs:1. Web browser sends request to web server2. Web server determines that it must start web application; determines

which one & starts it3. Web application starts, loads data sent by web server (primarily as

keys and their values; keys can duplicate)4. Web application responds (via stdout), with a header (saying what it’s

replying) followed by data5. Web application exits (quits) once done6. Web server passes this data on to user’s browser



CGI Alternatives

• FastCGI– Keeps web app alive (instead of restarting per request)– (+) Better performance (eliminates startup)– (-) More work developing app (must reset all state)– (-) Less robust (app must survive many requests)

• Server-specific (proprietary) APIs– (+) Even better performance (eliminates startup & IPC)– (-) Lock-in to a particular web server– (-) Even less robust (error may take down server)



AdaCGI Alternatives

• Doug Smith’s WebAda CGI– Derived from an old version of AdaCGI– (+) generic iterators, can remove keys, re-parser– (-) no cookies, complex use, buggy decoders, little doc, unmaintained– We’ve agreed that I’ll remerge his into mine (in time)– www.adasmith.com/webada/source

• Binding to C (ugh)• Un-CGI

– Converts CGI data to environment vars “WWW_name”– No cookies, multivalue keys ambiguous, slow, ugh



Why use Ada for Web Apps?

• Excellent Run-Time Performance– better than interpreters (Perl), can be > typical JVM– CGI low performance, so relevant iff compute-bound

• Excellent compile-time checking• Highly readable (especially vs. Perl)• Increased security over C/C++ (bounds checking)• Prefer Ada• Have existing Ada applications



Weaknesses of Ada forWeb Apps

• Wordiness (not best for short scripts)• Less convenient string handling• Regular expressions not built-in

– Can use GNAT’s library, but fewer capabilities and can’t optimize like Perl

• Fewer web-app-specific and related support libraries

• Often, must separately install Ada library



AdaCGI License

• AdaCGI is free, free software, open source• Open Source License: LGPL + 2 clauses:

– “GNAT clause”: don’t need to distribute separate object files– Web users must be able to get and redistribute your version of

the AdaCGI library

• Can use to develop proprietary programs, but the AdaCGI library must stay open



AdaCGI Basics

• “with CGI”: initialization autoloads data• Two ways to access CGI data:

– an associative array (given key & optional key count, returns value)

– indexed sequence (given index, =>key or value)

• Call Put_CGI_Header to start returning data– by default, to return HTML

• Then send results (HTML?) to standard out• Use String or Unbounded_String directly



“Minimal” Web App Example

with CGI, Text_IO; use CGI, Text_IO;procedure Minimal isbegin

Put_CGI_Header; -- We will reply with a generated HTML document.-- Output <HTML><HEAD>….</HEAD><BODY>:Put_HTML_Head("Minimal Form Demonstration”);if CGI.Input_Received then -- Check if input was received.Put_Variables; -- Input received; show all variable values.

else-- No input received; reply with a simple HTML form.Put_Line("<FORM METHOD=POST>What's your Name?<INPUT NAME=""name""><INPUT TYPE=""submit""></FORM>");

end if;Put_HTML_Tail; -- End HTML doc, sending </BODY></HTML>

end Minimal;



Debugging/Testing aWeb Program

• For debugging & test scripts, can start directly:– setenv REQUEST_METHOD GET– setenv QUERY_STRING key1=value1&key2=...– compile, link, run (“./minimal”)

• Output should look like:

Content-type: text/html

<HTML><HEAD><TITLE>Minimal Form Demonstration</TITLE></HEAD><BODY><FORM METHOD=POST>What’s your Name?<INPUT NAME="username"><INPUT TYPE="submit"></FORM></BODY></HTML>



Installing a Web Program

• To really use it, set up with web server, e.g.:– su– cp minimal /home/httpd/cgi-bin

• Run– http://localhost/cgi-bin/minimal– http://localhost/cgi-bin/minimal?

name=David%20Wheeler&[email protected]

• Odd problems? Try Put_Variables



Get vs. Post

• CGI supports two sub-protocols– Get: data can be included in URLs– Post: data can be voluminous

• AdaCGI supports both, merging them– Can use either subprotocol at any time– API hides difference; access data the same way– If you need to know, AdaCGI will say which, but using this

difference is not recommended



Cookies

• Cookies are small pieces of data– Sent by the server– Stored by the client and sent back when the client re-

communicates with the server

• Often used in e-commerce (the cookie is an ID indicating the transaction we’re in)

• Potential privacy risk: Permits servers to track users (loss of anonymity)



Security Issues

• CGI data comes from untrusted users– identify legal values, and prohibit anything not meeting the legal

criteria (min, max, patterns, etc.)– don’t assume that these values are trustworthy (“price”)– in particular, never trust a filename or directory name– you may need to escape all metacharacters– NIL character

• See the many documents available on CGI programming security



Additions in Version 1.5

• AdaCGI Version 1.5 added the following:– Cookie_Count– HTML_Encode: & becomes &– URL_Encode/Decode: % becomes %25– Generic Iterators– Key_Value_Exists: Has Key been given Value?

WebA

daInspired



Important Limitations

• No separate IndexedKey ADT/OO type for parameters & cookies

– parse, modify, remove, save, reload

• Doesn’t support file uploads– Rarely used in practice

• Only supports GET/POST commands– Others useful for web maintenance (WebDAV)



Less Important Limitations

• Auto-initializes data on startup• Doesn’t support FastCGI

– Usually implemented separately anyway

• Doesn’t auto-gen form with initial values– Can be done with a higher-level package

• String/Unbounded_String awkward• Some subprogram names too similar• Could be broken into multiple packages (?!)



AdaCGI Spec: Get-by-key

• function Value(Key : in String;Index : in Positive := 1;Required : in Boolean := False)

return Unbounded_String;• function Key_Exists(Key : in String;

Index : in Positive := 1)return Boolean;

• function Key_Count(Key : in String)return Natural;



AdaCGI Spec: Get-by-Position

• function Argument_Count return Natural;• function Key(Position : in Positive) return String;• function Value(Position : in Positive)

return String;



AdaCGI Spec: Starting Output

• procedure Put_CGI_Header(Header : in String := "Content-type: text/html");

– Puts CGI Header to Current_Output, followed by two carriage returns.– This header determines the program’s reply type.– Default is to return a generated HTML document.– Warning: Make calls to Set_Cookie before calling this procedure!



AdaCGI Spec:Generating HTML Basics

• procedure Put_HTML_Head(Title : in String;Mail_To : in String := "");

– Puts an HTML header with title “Title”: <HTML><HEAD><TITLE> _Title_ </TITLE><LINK REV="made" HREF="mailto: _Mail_To_ "></HEAD><BODY>

• procedure Put_HTML_Heading(Title : in String;Level : in Positive);

– Put an HTML heading, e.g. <H1>Title</H1>.

• procedure Put_HTML_Tail;– P ut HTML tail, I.e.: </BODY></HTML>



AdaCGI Spec: Watch Out, Excessively Similar Names!

• Put_CGI_Header– Content-type: text/html

• Put_HTML_Head – <HTML><HEAD>…</HEAD><BODY>

• Put_HTML_Heading– <H1>…</H1>



AdaCGI Spec:Generating HTML Miscellania

• procedure Put_Error_Message(Message : in String);– This Puts an HTML_Head, an HTML_Heading, the message, and an

HTML_Tail.– Call "Put_CGI_Header" before calling this.

• procedure Put_Variables;– Put to Current_Output all of the CGI variables as an HTML-formatted

String.



AdaCGI Spec: Miscellaneous

• function Input_Received return Boolean• function My_URL return String;• function Get_Environment(Variable : in String) return String;• Line_Count, Line_Count_of_Value, Line, Value_of_Line:

handle multi-line values



AdaCGI Spec: Cookies(new feature of AdaCGI 1.4)

• Set_Cookie(Key : String;Value : String;Expires : String := "";Path: String := …; Domain: String := …;Secure: Boolean := False );– Sets a cookie value; call this BEFORE calling Put_CGI_Header.

• function Cookie_Value(Key : in String;Index : in Positive := 1; Required : in Boolean := False)

return Unbounded_String;• function Cookie_Value(Position : in Positive) return String;



“Search” Example: Top

with CGI, …; use CGI, …;procedure Search is ...begin

Put_CGI_Header;if Key_Exists("query") and Key_Exists("file") then

Process_Query;else

Generate_Blank_Form;end if;Put_HTML_Tail;

end Search;



“Search” Example:Generate_Blank_Form (1 of 4)

Put_HTML_Head("Text Search Form");Put_HTML_Heading("Text Search Form", 1);Put_Line("<P>You may search for a text phrase from any of the given files.<P><FORM METHOD=POST>");

Put_Line("What do you want to search for:<P>");declare

Query_String : constant String := CGI.Value ("query");File_Value : constant String := CGI.Value ("file");

beginPut_Line("<INPUT NAME=""query"" SIZE=40");if Query_String /= "" then - - if query set, use as default

Put(" VALUE="); Put(String’(Value("query")));end if;Put_Line("><P>");




- - if file set, then save it in form & display its value.- - otherwise, let the user select the file to search.if Key_Exists("file") and File_Value /= "" then

Put("<INPUT TYPE=""hidden"" NAME=""file"" VALUE=""");Put(String’(Value("file") & """>"));Put("<P>You will be searching file <I>");Put(String’(Value("file")));Put_Line("</I><P>");

elsePut_Line("Where do you want to search?<P>");Put_Select_List;

end if;end; -- declare block




- - if “casesensitive” set, save in form invisibly, else ask userif Key_Exists("casesensitive") thenPut_Line(String’("<INPUT TYPE=""hidden"" NAME=""casesensitive""

VALUE=""" & Value("casesensitive") & """>"));elsePut_Line("Do you want this search to be case-sensitive?");Put_Line(”<DL><DD><INPUT TYPE=""radio""

NAME=""casesensitive" " VALUE=""yes""> <I>Yes.</I>");Put_Line("<DD><INPUT TYPE=""radio"" NAME=""casesensitive""

VALUE=""no"" CHECKED> <I>No.</I>");Put_Line("</DL>");

end if;




- - Generate submit and reset buttons for formPut_Line("<P> <INPUT TYPE=""submit"" VALUE=""Submit Query"">");Put_Line("<INPUT TYPE=""reset""> ");Put_Line("</FORM>");



“Search” Example:Process_Query (1 of 2)

procedure Process_Query isUser_File_To_Search : constant String := CGI.Value("file");File_To_Search : constant String := - - Don’t trust user to set this!

Real_File_Name(U(User_File_To_Search));Pattern : constant String := Value("query");Case_Sensitive : Boolean := False;Case_Sensitivity : constant String := Value ("casesensitive");

beginPut_HTML_Head("Query Result");Put_HTML_Heading("Query Result", 1);Put_Line(String’("<P>The search for <I>" & Value("query") & "</I>"));Put_Line(String’(" in file <I>" & Value("file") & "</I>"));



“Search” Example:Process_Query (2 of 2)

if Case_Sensitivity = "yes" thenCase_Sensitive := True;Put_Line(" in a case-sensitive manner");

end if;

Put_Line("produced the following result:<P>");Put_Line("<PRE>");Flush;Put_Matches(File_To_Search, Pattern, Case_Sensitive);Put_Line("</PRE>");

end Process_Query;



In Conclusion...

• You can make web apps in Ada!– Get it at http://www.dwheeler.com/adacgi– EMailing: [email protected] message body

“subscribe”– Linux packaging: http://www.gnuada.org

• Use the current version of AdaCGI– Currently version 1.5

• Patches welcome• Go forth & have fun!



Introduction to XML

Currie ColketMITRE



Motivation for XML

HTML Dumbs Down

Book

Author Date ISBN PublisherTitle

<html>...<P>Title: Programming in Ada95 (Second Edition)<Br>Author: John Barnes<Br>Date: July, 1998 <Br>ISBN: 0-201-34293-6 <Br>Publisher: Addison-Wesley <Br> </P>... </html>

Useful for Presentation onlyLimited Content accessibility



What is XML• Produced by W3C as recommendation; voted on by Consortium members

http://www.w3.org/XML/• XML is a method for putting structured data in a text file• XML looks a bit like HTML but isn't HTML

tags delimit data; in HTML tags communicate presentation• XML is text, but isn't meant to be read

strict rules; a forgotten tag makes the entire file useless• XML is a family of specifications

XML 1.0 - specifies tags and attributes, and Document Type Definition (DTD) guidelinesXlink - describes a standard way to add links to an XML file

Xpointers and Xfragments point to portions of an XML fileCSS - Cascading Style Sheets provide mechanism to present content documents XSL - Extensible Style Language is the advanced language for expressing style sheetsXSLT - Transformations (XSLT) is the semantics for transforming one

XML document into anotherDOM - Document Object Model allows programs and scripts to dynamically access

and update the content, structure and style of documentsXML Namespaces - specifies how you can associate a URL with every single tag

and attribute in an XML documentRDF - Resource Description Framework (RDF) is a foundation for processing metadata;

it provides interoperability between applications that exchange data on the Web. Xschema - Specifications help developers define their own schemas

and many more



XML Interfaces

HTMLBrowserUser 1

“Produce content once and output in many different formats.”

DTD

XMLApplicationProcessing

XML

Validation

XML Parsere.g., msxml

Other XMLApps

DOM

HTMLBrowserUser 2

XSL1 XSL

2

Outputfor

Printer

XSL3

DatabaseQuery

Application

From library of common DTDs



XML Schema Example

Book*

Author+ Date ISBN Publisher

Book_Catalogue

Title

Month? Year

Note: “*” means “zero or many”“?” means “is optional ”“+” means “one or more”

Attributes for each book:Category - autobiography/non-fiction/fiction In_Stock - yes/no (no default)Reviewer - null default

XML DTD Example

<!ELEMENT Book_Catalogue (Book)*><!ELEMENT Book (Title, Author+, Date, ISBN, Publisher)>   <!ATTLIST Book

Category (autobiography | non-fiction | fiction) #REQUIREDIn_Stock (yes | no) “no”Reviewer CDATA “” >

<!ELEMENT Title (#PCDATA)><!ELEMENT Author (#PCDATA)><!ELEMENT Date (Month?, Year)><!ELEMENT ISBN (#PCDATA)><!ELEMENT Publisher (#PCDATA)><!ELEMENT Month (#PCDATA)><!ELEMENT Year (#PCDATA)>

Book_Catalogue.dtd



XML Code Example<xml version=“1.0”><!DOCTYPE Book_Catalogue SYSTEM “http://www.DTD_host.org/Book_Catalogue.dtd”><Book_Catalogue>

<Book Category = “non-fiction”In_Stock = “yes”Reviewer = “Pat Rogers”>

<Title>Programming in Ada95 (Second Edition)</Title><Author>John Barnes</Author><Date>

<Year>1998</Year></Date><ISBN>0-201-34293-6</ISBN><Publisher>Addison-Wesley</Publisher>

</Book><Book

Category = “non-fiction”In_Stock = “no”Reviewer = “Ted Baker”>

<Title>Ada 95: Problem Solving and Program Design, 3rd Edition</Title><Author>Michael Feldman</Author><Author>Elliot Koffman</Author><Date>

<Month>July</Month><Year>1999</Year>

</Date><ISBN>0-201-36123-X</ISBN><Publisher>Addison-Wesley</Publisher>

</Book></Book_Catalogue>

Book_Catalogue.xml

Need to suckin the DTD file



What is XHTML● Produced by W3C as recommendation; voted on by Consortium members

http://www.w3.org/TR/xhtml1/● Reformulation of HTML 4.0 in XML 1.0● XHTML is intended to be used in conjunction with tags from other X3 tag

sets , so that in principle, you can combine XHTML tags with:● XML tags● Scalable Vector Graphics (SVG) tags● Synchronized Multimedia Integration Language (SMIL) tags● Mathematical Markup Language (MathML) tags● etc.

● XML syntax is used for XHTML, for example:● Make tags case-sensitive ● Include end tags e.g. </p> and </li> ● Add a / to empty tags, e.g. <br /> and <hr /> ● Quote all attribute values, e.g. <img src="duck.jpg" /> ● Use lower-case for tags and attributes

● Old browsers can render XHTML 1.0 if simple guidelines are followed. ● New specification for FORMS based on Data, Logic, and Presentation● New specification for Modules to subset and extend XHTML



XML Observations/Opinions

● Technology in early adopter phase - Too early for true lessons learned

● Phenomenal Excitement: XML is the latest “web thing”● Low Barriers to Entry - Incremental development, low

investment requirements● Significant Industry Offerings in products and tools -

Reaching critical massAlready internet output for Word in Microsoft Office instead of HTML

● Cross Disciplines- Unifying framework for exchanging data

● Requires Tools - Specialized tools needed to develop and use XML; not supported by many browsers

● HTML Still Viable - XML will not replace HTML for basic presentation of information for many years, if ever



Summary• Introduction to WWW and SIGAda Home Page as Notional Example • Introduction to HTML and use of Netscape Composer • Effective Design Strategies Appropriate to Disseminating Information• Tools to Manage Development of Web Pages• Introduction to Ada CGI• Using ACM WWW and Maillist Facilities • Introduction to XML

You should now be able to:• Use simple web-authoring tools• Develop your own Home Page• Tailor it to effectively communicate to your audience• Establish Home Page on ACM host• Use simple web-posting tools• Use simple web-verification tools• Establish maillists for your activity

We are looking for volunteers to “own” portions of the ACM SIGAda Home PagePlease contact us if you are interested!