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http://www.easytools.com/festival.zip

Developing browser based applications[SysReader Programmers Festival ‘97]

T.N.C.Venkata RanganVishwak AssociatesChennai - 600 033

www: http://www.easytools.comemail: [email protected]

Phone: 489 9109

http://www.easytools.com/


Conventional Front Ends

•Powersoft PowerBuilder•Oracle forms•Microsoft Visual Basic•Borland dBase/Microsoft Foxpro•CA-Clipper•C/C++•Borland Delphi


Conventional … Advantages

•Familiarity and Experience with them

•Reliability

•Connectivity (with backend databases)


Conventional … Disadvantages

•Portability problems •Compatibility problems

•Distribution & Installation•Support and TroubleShooting

•Complexity to Developers •Inconsistent UI between various Apps.•Restricted navigation for the user

•Security on different Modules


HTML based Forms + Client/Server Side Programming + Database Source/Server

= Browser based Applications

Browser based Apps?Browser based Apps?


•Consistent UI between different Applications•Familiar browser paradigm of navigation•Internet/Web Standards

•Installation

•Browsers are inexpensive and some are free

Browser ... AdvantagesBrowser ... Advantages


HTML - An Example

<HTML><HEAD><TITLE>Welcome</TITLE></HEAD><BODY>

Hello World!</BODY></HTML>


ActiveX Controls (.ocx)ActiveX Documents (.vbd)

Client Side ProgrammingClient Side Programming

The ACTIVE way [Can I say that as the Microsoft way? :-)]

The JAVA Way [Is it the Programming Nirvana? :-)]


ActiveX is basically a specification for interfaces between objects.

What is ActiveX … ???What is ActiveX … ???

ActiveX Controls makes up the components used to build other applications, whereas ActiveX Documents is the program.

ActiveX Documents may be loosely called as a sophisticated Form Object.

You don’t, for example, put a bunch of ActiveX Documents on a form, as you do ActiveX controls on it.


Tools to build ActiveX ...Tools to build ActiveX ...

Microsoft Visual Basic 5.0Microsoft Visual C++ 4.x or aboveMicrosoft Visual J++Borland Delphi 3.x

Tip: VB 5.0 can directly convert your VB 4.0+ forms into ActiveX controls.


ActiveX - Will it run in ...?ActiveX - Will it run in ...?

ActiveX is supported in IE 3.0 and aboveRuns in Navigator 3.x and above provided you have NCompass labs Plug-in installed:-(

Note:If the ActiveX control or document is developed in VB/VC++/VJ++ you require the respective supporting libraries/DLLs/VM.ActiveX controls are Auto downloadable ! :-)


Sample HTML with ActiveXSample HTML with ActiveX

<HTML><HEAD><TITLE>VB Form into ActiveX Control inside browser </TITLE></HEAD><BODY><OBJECT ID="UserControl11" WIDTH=557 HEIGHT=442CLASSID="CLSID:1DDBB7E7-62BB-11D1-AA70-008048FD3FDA"> <PARAM NAME="_ExtentX" VALUE="11790"> <PARAM NAME="_ExtentY" VALUE="9335"></OBJECT><H2> I have my VB 5.0 form as an ActiveX control inside IE 4.0 now.</H2></BODY></HTML>


JAVAJAVA

JAVA: A simple, object-oriented, distributed, interpreted, robust, secure, architecture neutral, portable, high-performance, multi-threaded, and dynamic language.

A JAVA Applet is a JAVA program that adheres to a set of conventions that allows it to run within a JAVA-compatible browser.


JAVA - SampleJAVA - Sample

<HTML><HEAD><TITLE>A Simple Program</TITLE></HEAD><BODY>Here is the output of my program:<APPLET CODE=“HelloWorld.class” WIDTH=150 HEIGHT=25></APPLET></BODY></HTML>


JAVA - Sample AppletJAVA - Sample Applet

import java.applet.Applet;import java.awt.Graphics;

public class HelloWorld extends Applet { public void paint(Graphics g) { g.drawString("Hello world!", 50, 25); }}

HelloWorld.java


JAVA - Sample AppletJAVA - Sample Applet


Client Side… AdvantagesClient Side… Advantages

•Easier conversion •Server load is reduced•Interactivity•Reduced Network traffic


Client Side … DisadvantagesClient Side … Disadvantages

•Code is visible to users•Limited Portability •Restricted Browser independence•Requires powerful clients


Server Side ProgrammingServer Side Programming

Active Server Pages (ASP)

PERL and other CGI tools

Microsoft ISAPI & Netscape NSAPI

JAVA Servers from Sun & Netscape


Server Side Programming


ASP - An Example

<HTML><HEAD><TITLE>ASP Example</TITLE></HEAD><BODY><% for i=1 to 7 %><FONT SIZE=<%=i%>>Hello World!</FONT><BR><% Next %></BODY></HTML>


ASP - An Example


<HTML><HEAD><TITLE>ASP Example</TITLE></HEAD><BODY>

<FONT SIZE=4>Hello World!</FONT><BR><FONT SIZE=5>Hello World!</FONT><BR><FONT SIZE=6>Hello World!</FONT><BR><FONT SIZE=7>Hello World!</FONT><BR>

</BODY></HTML>

ASP - An Example


Form Processing - HTML (eating.html)

<HTML><HEAD><TITLE>Sample Form</TITLE></HEAD><BODY><CENTER><H1>Late-night programmers eating habits</H1>Check all that apply<P><TABLE><TR><TD ALIGN=LEFT>

<FORM ACTION=”eating.asp" METHOD=POST TARGET="_top"><INPUT TYPE="CHECKBOX" NAME="chk" value="Pizza">Pizza<BR><INPUT TYPE="CHECKBOX" NAME="chk" value="Coffee">Coffee<BR><INPUT TYPE="CHECKBOX" NAME="chk" value="Chips">Chips<P><INPUT TYPE=SUBMIT VALUE="Submit"></FORM>

</TD></TR></TABLE>

</CENTER></BODY></HTML>


Form Processing - HTML (eating.html)


<HTML><HEAD><TITLE>Sample Form Processing</TITLE></HEAD><BODY><CENTER><H1>Late-night programmers eating habits</H1>Your choices<P></CENTER><B>You like:</B><BR><%=Request("chk")%><BR></BODY></HTML>

Form Processing - ASP (eating.asp)


Form Processing - ASP (eating.asp)


<HTML><HTML><HEAD><TITLE><HEAD><TITLE>Project listProject list</TITLE></HEAD></TITLE></HEAD><BODY><BODY><%<%

'----- Open the database, create the record set'----- Open the database, create the record set

Set cn = Server.CreateObject ("ADODB.Connection")Set cn = Server.CreateObject ("ADODB.Connection")

cn.Open "dsn=ProjList;database=ProjInfo;uid=;pwd=;"cn.Open "dsn=ProjList;database=ProjInfo;uid=;pwd=;"

Set rs = cn.Execute ("select ProjName, ProjMgr, DueDateSet rs = cn.Execute ("select ProjName, ProjMgr, DueDate

fromfrom Projects order by DueDate")Projects order by DueDate")

ADO Sample CodeADO Sample Code


Response.Write ("Response.Write ("<CENTER><TABLE><CENTER><TABLE>")")

'----- Captions'----- Captions

Response.Write ("Response.Write ("<TR><TR>")")

for iCol = 0 to rs.Fields.Count - 1'for iCol = 0 to rs.Fields.Count - 1'

Response.Write ("Response.Write ("<TD><CENTER><TD><CENTER>") ")

Response.Write (rs(iCol).Name)Response.Write (rs(iCol).Name)

Response.Write ("Response.Write ("</CENTER></TD></CENTER></TD>")")

nextnext

Response.Write ("Response.Write ("</TR></TR>")")



'----- Data rows'----- Data rowsdo while not rs.eofdo while not rs.eof

Response.Write ("Response.Write ("<TR><TR>")")for iCol = 0 to rs.Fields.Count - 1for iCol = 0 to rs.Fields.Count - 1

Response.Write ("Response.Write ("<TD><TD>")")Response.Write (rs(iCol))Response.Write (rs(iCol))Response.Write ("Response.Write ("</TD></TD>")")

nextnextResponse.Write ("Response.Write ("</TR></TR>")")rs.MoveNextrs.MoveNext

looploop



Response.Write ("Response.Write ("</TABLE></CENTER></TABLE></CENTER>")")

rs.Closers.Close

cn.Closecn.Close

%>%>

</BODY></BODY>

</HTML></HTML>



PERLPERL

PERL stands for Practical Extraction and Report Language.

Larry Wall (creator of PERL) loves to call it Pathologically Eclectic Rubbish Lister


PERL - AdvantagesPERL - Advantages

•FREE of cost•Popularity•Available for many platforms

•Socket Support •Pattern Matching (ideal for searching text)•Flexible Text handling (No details to worry)

•Newer packages for Win32 support ODBC


PERL - SamplePERL - Sample

sub getFormData { my($buffer) = "";

if ($ENV{'REQUEST_METHOD'} eq 'GET') { $buffer = $ENV{'QUERY_STRING'}; } else { read(STDIN, $buffer,$ENV{'CONTENT_LENGTH'}); }}


Server Side… AdvantagesServer Side… Advantages

•Instant Portability-Platform Independence•No manual installation •Easy/Auto Distribution (upgrades too)

•Scalability•Runs in thin clients•Data + Code resides only in the Server•Code (Core business logics) are secure•No need of seperate S/W client licenses

•No compilation process for ASP & PERL


Server Side… DisadvantagesServer Side… Disadvantages

•Learning curve (because of New tools)•Server is overloaded?•Server licenses are expensive•Speed (both ASP & PERL are interpreted)


Decision ?Decision ?Develop. Ease of development not only means that an application can cost less to develop, it means that the team's skills can be better utilized.Scale. It is possible to build a single application that can be used by virtually any number of users—simultaneously. Maintain. Customer requirements change, businesses change, business needs change and will continue to change while the team adapts existing systems to last week's changes.Deploy. Systems should be easy to install and should easily be upgraded to the newer versions.Use. The application must not only work responsively, it must anticipate user needs,


Programming PERL - Larry WallProgramming PERL - Larry WallHTML The definitive guide - Musciano & KennedyHTML The definitive guide - Musciano & KennedyJavaScript Programming - Reaz HoqueJavaScript Programming - Reaz HoqueUnderstanding ActiveX & OLE - David ChappellUnderstanding ActiveX & OLE - David ChappellActive Visual Basic 5.0 - Eddon & EddonActive Visual Basic 5.0 - Eddon & EddonThe JAVA Tutorial - Campione & WalrathThe JAVA Tutorial - Campione & WalrathUnlocking Active Server Pages - Christoph WilleUnlocking Active Server Pages - Christoph Wille

Reference BooksReference Books


www.perl.orgwww.activestate.comwww.activestate.comwww.w3c.orgwww.w3c.orgdeveloper.netscape.comdeveloper.netscape.comwww.javasoft.comwww.javasoft.com

www.microsoft.com/iis/default.aspwww.microsoft.com/iis/evaluating/guides

/whitepapers/aspwp.htmwww.microsoft.com/msdn

World Wide WebWorld Wide Web

http://. zip developing browser based applications [sysreader programmers festival ‘97]...

Documents

activex controls

bunch of activex documents

java applet

java program

java way

javacompatible browser

microsoft visual c

microsoft way