Lecture 25 - University of Massachusetts Amherst · 2010. 12. 7. · 4 HTML and script are returned to browser 5 Web browser processes script to create HTML Tom Horton Alfred C. Weaver

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UNIVERSITY OF MASSACHUSETTS AMHERST •• CMPSCI 120 Fall 2010

Lecture 25

Server Side


AnnouncementsProject 3 (final project) now due 12/17HW#10: two surveys and will be due 12/17post tonight?

Any questions on Yariv’s lecture on privacy,security?Yes, it will be covered on the exam!

Extended office hours this week & nextToday 11:00 AM-noon and 1:30-2:45 PMThursday 3-5:00 PMMonday 10:30 AM-noon

Final will cover JSBE 1-12, 15; review ThursdayDecember 14th 8-10:00am, Goessmann 64Open book + handouts + 3x5 file card

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Web services vs. web programming

web services = remote procedure callSOAPstructured data (XML)methods and responsesregistration & discoverygenerally, for machine consumption

web programming generate HTML pagesfor humansoften, database-drivenreplacement for IBM 3270 terminals ...

adapted from Henning Schulzrinne Advanced Programming Columbia U.


Client vs. server programmingexecute code on client : JavaScript, JavaJavaScript (aka ECMAscript):

modify and get values from HTML ("document objectmodel" – DOM)

download Java applet self-contained programmingenvironment

Execute code on server generate documentstate maintenance (HTTP stateless)

login, shopping cart, preferences

HTML-centric vs. program-centricHTML-centric: PHP, ASPcgi, fast-cgi(Java) servlet

adapted from Henning Schulzrinne Advanced Programming Columbia U.

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Taxonomy

JavaScript

SSI, ASP,PHP, JSP,

CFM

embedded inHTML separate

Java applets,plug-inclient

server API(NSAPI), cgi,

servletsserver

adapted from Henning Schulzrinne AdvancedProgramming Columbia U.


Static Web Page Delivery

Web Server

Client

1Author writesHTML

2Client requests page

3 Web server locates .htm file

HTML stream returned to browser4

5Browserprocessespage

Tom HortonAlfred C. WeaverCS453 Electronic Commerce

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UNIVERSITY OF MASSACHUSETTS AMHERST •• CMPSCI 120 Fall 2010 7

Dynamic Web Page Delivery

Web Server

Client

1Author writesinstructions


3 Web server locates instructions file

6 Browser displays HTML

HTML and script are returned to browser4

5Web browser processes scriptto create HTML



HTML Forms

Provide GUI-like components in your page Inputs: buttons, textboxes, radio

buttons, selections Output fields: text boxes etc.

Can send information to the server Can be accessed by JavaScript code on

the client-side I found this

http://www-edlab.cs.umass.edu/cs120/ClassDemos/JSExamples/forms.html

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JavaScript – DOMJavaScript and HTML FormsWindow.document.formA form is a property of the document butis also an objectForm elements are properties of a formand are also objectsAccess to form’s properties is donethrough the name attribute of the formtagAccess to the properties of the formelements is done through the nameattributes of the particular form element


InteractiveProgrammingon the Internet -- Knuckles

function plus(){ var n1;

var n2;n1=document.addmult.num1.value;n2=document.addmult.num2.value;

n1=parseFloat(n1);n2=parseFloat(n2);

document.addmult.result.value=n1+n2;}function times(){

var n1;var n2;n1=document.addmult.num1.value;n2=document.addmult.num2.value;

n1=parseFloat(n1);n2=parseFloat(n2);

document.addmult.result.value=n1*n2;}

<body bgcolor="#ffffcc"><p><form name=addmult> <p>enter a number in each field: <input type=text name=num1 value="" size=5> <input type=text name=num2 value="" size=5><br> <input type=button value="+" onclick="plus()"> <input type=button value="*" onclick="times()"><br> <input type=reset value="reset form"><br> <textarea name=result rows=3 cols=27 wrap=virtual></textarea></form>

exampleJavaScript and HTML Forms

http://www-edlab.cs.umass.edu/cs120/ClassDemos/JSExamples/FormExample1.html

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• Form for submitting info for server side processing exampleJavaScript and HTML Forms

InteractiveProgrammingon the Internet -- Knuckles

http://www-edlab.cs.umass.edu/cs120/ClassDemos/JSExamples/FormExample2.html


Example: JavaScript – cookiesvar expires = new Date()var today = new Date()function setCookie(name, value, hours) { var expire = new Date(); expire.setTime (expire.getTime() + (1000 * 60 * 60 * hours)); document.cookie = name + "=" + escape(value) + ((expire == null) ? "" : ("; expires=" + expire.toGMTString()))}function unsetCookie(name) { var exp = new Date(); exp.setTime(today.getTime() - 10); document.cookie = name + "=" + "; expires=" + exp.toGMTString()}expires.setTime(today.getTime() + 86400*365)

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UNIVERSITY OF MASSACHUSETTS AMHERST •• CMPSCI 120 Fall 2010 13

Server-side Dynamic Page Delivery

Client

Web Server1Author writesinstructions


3 Web server locates instructions file

HTML stream returned to browser5

6Browser processespage

4 Web server processes instructions to create HTML

Lots of processing can happen on the server before returning a webpage to the clientRun programs in a scripting language (e.g. ASP)Manage sessionsCookiesSessions, shopping baskets, log-ins, etc.

Database processing



Server Side Includes (SSI).shtml documents (or configured by default for all.html documents)include in HMTL/XML commentsThis is done when the page is requested and the userwill see nothing different to if the text (or code) wasalready there

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Server Side Includes (SSI)configsets the error-message format, time, or size

echoinserts the variable values of an ssi into your webpage

flastmodinserts a date/time stamp of when a file was lastupdated

fsizewill insert the size of a file into your web page

includeinsert the content of an HTML file into your webpage


SSI Example

<body><h1>SSI Test</h1>The document was last modified on and has This would be the same even if it was on the pagewww.mysite.com/index.htm orwww.mysite.com/html/files/myfile.htm

update all the pages by just changing this one page.use SSI to execute a CGI script on your server

text counters, advanced advert rotations, randomtext and images and several other extras on yourweb pages

one of the best uses of SSI

Security issues: exec


Client Server Strategies

CGI (Common Gateway Interface)Active Server PagesPersonal Home Pages (PHP)MS Active Server Pages (ASP)Cold Fusion

Java Servlets and JSPEnterprise Java Beans

CS-422Enterprise ComputingDick Steflik

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Common gateway interface (cgi)

Earliest attempt at dynamic web contentpre- HTTP, rooted in gopherreliableresource hog

Program run by web server in response toclient requestlanguage-independentperl, C, C++, VB, Java, python, tcl

passes HTTP request information viacommand line (ISINDEX) – rarely usedenvironment variables: system info + querystring (GET)request body (POST) standard input

return HTML or XML via standard outputCS-422Enterprise ComputingDick Steflik


CGI (more)

Very useful used in conjunction withJava based clients for things like:Report Generation (WebFocus)Data retrieval (files and RDBMS)Persistent object storage (files)

Could almost be replaced by server sideJavaHard to maintain program statemust rely on programming tricks

cookies, hidden variablesCS-422Enterprise ComputingDick Steflik

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Browser

Web

Server

DBCGI

Program

Static Web page with forms tags<form action=/CGI-BIN/AAA.PL>

CGI

Example:<form action=scripturi method=GET|POST>form fields:<input type="text" name="text1" size=10

maxlength=15 value="Initial text"><input type="hidden" name="state" value="secret"><input type=radio name=radio value=WNYC checked><input type=radio name=radio value=KQED><input type=submit value="Submit">



CGI (more) If another user requests a CGI while the CGI is alreadyrunning; the web server spawns a child process andruns another instance of the CGI there.

For frequently run CGIs there may be many copies inthe machine at the same time

…resource hog (web servers that run a lot of CGIs willuse all of the memory you can afford)

Browser

Web

Server

DBCGI

Program

CGI

Program

CGI

Program

Browser Browser


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Active Server Page Technologies

HTML pages that appear to be database awareHTML with an embedded scripting languageand either CGI or proprietary server supportare used to make forms objects appear to bedatabase awareMain contenders:PHP (Open Source)Microsoft Active Server Pages (OEM Product)Cold Fusion (OEM Product)Java Server Pages (Open licensing from Sun)



PHP (Personal Home Pages)Core TechnologiesHTMLPHP ScriptJavaScript

PlatformsPrimarily LINUX, ApacheWindowsUNIX

DatabasesPrimarily used with MySQL (Open Source)Oracle, DB2 (MyODBC Open SourceDatabase Driver))


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PHP How it worksPHP processor usually installs as a CGI that isinvoked in response to a request for a .php file(on Windows NT can run as a service)

the CGI retrieves the requested file, parses itlooking for PHP tags

PHP tags are resolved and the tag is replaces bythat resolution

Apache Web Server

MySQL DB

HTML

JavaScript

PHP CGI CS-422Enterprise ComputingDick Steflik


Creating PHP Code BlocksCode declaration blocks are separatesections within a Web page that areinterpreted by the scripting engineThere are four types of code declarationblocks:Standard PHP script delimitersThe standard method of writing PHP codedeclaration blocks is to use the <?php and?> script delimiters

The <script> elementShort PHP script delimitersASP-style script delimiters

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PHP Programming

Displaying Script ResultsThe echo() and print() statements arelanguage constructs of the PHPprogramming languageA programming language constructrefers to a built-in feature of aprogramming languageThe echo() and print() statements arevirtually identical except:The print() statement returns a value of 1if it is successfulIt returns a value of 0 if it is notsuccessful


PHP Programming

Multiple Code Declaration BlocksFor multiple script sections in a document, include aseparate code declaration block for each section

...</head><body><h1>Multiple Script Sections</h1><h2>First Script Section</h2><?php echo “<p>Output from the first script section.</p>”;?><h2>Second Script Section</h2><?php echo “<p>Output from the second script section.</p>”;?></body></html>

PHP code declaration blocks execute on a Web serverbefore a Web page is sent to a client

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Example<?php

// Load the PHP-GTK extension

$extension = "php_gtk" . (strpos(PHP_OS, "WIN") >= 0 ? ".dll" : ".so");

dl($extension);

// Create a new window

$window = &new GtkWindow();

$window->set_title("Test App");

$window->set_usize(300, 50);

$window->set_position(GTK_WIN_POS_CENTER);

$window->set_policy(false, false, false);

// Set a callback function for the destroy signal

$window->connect("destroy", "killwin");

function killwin()

{

echo("Window Destroyed!\n");

gtk::main_quit();

}

// Add a GtkVBox class to our window

$box = &new GtkVBox();

$window->add($box);

// Add a GtkEntry class to our window

$entry = &new GtkEntry();

$entry->set_text("Hello World");

$box->pack_start($entry);

// Add a GtkButton class to our window

$button = &new GtkButton("Reverse Text");

$button->connect("clicked", "reverseText", $entry);

$box->pack_start($button);

function reverseText($theButton, $theEntry)

{

$text = strrev($theEntry->get_text());

$theEntry->set_text($text);

}

// Show the window

$window->show_all();

// Start the main PHP-GTK listener loop

gtk::main();

?>


Advantages of PHP

Light-weightCross-platform compatibleProcedural / Object OrientedprogrammingSupports wide range of DatabasesSupports wide variety of outputsSupports wide variety of protocolsExtremely useful text processingfeatures

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PHP

BenefitsCheap, Open SourceEasy to learnspecial HTML-like tagsvery reminiscent of C

many Open Source, domain specificadd ons available

ProblemsSupport is typical of Open Source(but quality is high)



Microsoft Active Server Pages

Core technologiesMS Internet Information ServerMS Internet Explorer (IE4.0)VBScriptJavaActiveXSQL Server & AccessDCOM

Works only on Windows (NT Server andW2000 Server)

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Data Base,(Access

SQLServer)

VBScript

HTML

JavaScriptVBScript

IIS

Java

ActiveX

IE 4.0


Microsoft ASP Architecture



Microsoft ASPHow it works

IIS retrieves the requested file, parses it looking forJscript/VBScript and resolves the script by replacing it withthe resolution (values/text)

BenefitsA 100% MS solution, important for many corporate ISshops

Easy to learnbased on VBskills are readily available from the large number of VBprogrammers

easy accessibility to Windows API and DLLsProblems

Security has always been a problem due to MS frequent OSand product release cycle

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PHP vs. ASP

PHP is fasterSuperior Memory ManagementCloser to C Style of ProgrammingCross Platform Migration StrategyDynamic generation of UI is moreflexible



Java Servlets

Core TechnologiesJavaHTML, Javascript

PlatformsNT, LINUX, SolarisApache/Tomcat, Netscape/iPlanet,JRun

Databasesall JDBC enabled (DB2, Oracle,Sybase, Informix)

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HTML

JavaScript Web Serverwith servlet

engine & JRE

Database

Servlet

Cache


Java Servlet Architecture



Java ServletsHow it works

Web server receives request for servlet (name is mapped toa class file by Java web server) . Servlet is loaded into cacheand run in the JRE. HTML produced by servlet is returned tobrowser

BenefitsCross platform as long as compliant servlet engine isavailabe

Easy to learn for Java/C++ programmersmuch support available via the webfaster than interpretive technologies (like PHP, ASP, CF)

Problemsstill hard to find skillsstill considered to be “bleeding edge” by many IS shops

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Java Server Pages

Core TechnologiesJavaHTML, Javascript

PlatformsNT, LINUX, SolarisApache/Tomcat, Netscape/iPlanet,JRun

Databases all JDBC enabled (DB2, Oracle,Sybase, Informix)


JSP Architecture

HTML

JavaScript Web Server with

JSP engine &JRE

Database

Servlet

Cache


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What is a JSP

Combination of HTML, Javascript,and a set of Java tags (5)Java tags allow java code and callsto Javabeans to be embedded inlineJava tags also allow control of theJava runtime environment



Java Server PagesHow it worksWeb server receives request for .jsp. JSP engineconverts the page to source code for a Java Servlet,source is compiled by javac and class is moved tocache for deployment

BenefitsCross platform as long as compliant engine is availabeAllows Integrated Product Team developmentfaster than interpretive technologies (like PHP, ASP,CF)

Problemsstill hard to find skillsstill considered to be “very bleeding edge” by many ISshops

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PHP vs. JSPPHP is faster in execution timeA recent survey in ZDnet's eWeekonline publication found that PHP is asmuch as 3.5 times faster than JSPFaster in development time – flatterlearning curvePHP supports any 32-bit or betterplatform, whereas JSP supports onlyplatforms that have a Java virtualmachine available



Cold FusionCore TechnologiesProprietary, tag based, embeddedscripting languageJavascript, Java

PlatformsNT, LINUX, SolarisApache, Netscape/iPlanet, IIS

DatabasesAccess, MS SQL Server (NT W/2000Only)Sybase, Oracle, DB2MySQL (requires MYODBC driver)

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Cold Fusion Architecture

Database

HTML

JavaScript Web Server

ColdFusion

Server

ODBC

JDBC

Native

Java




Cold FusionHow it worksWeb server receives request for .cfm file and passesthe request to the CF server. CF Server parses the filereturning all non- CF tags to the requesting browserand resolving the CF tags into their resolvedtext/values

BenefitsMulti-platformEasy to learn

tag based (looks like HTML, gives web community comfortthat its just some additional tags)

much support available via the web, wide following inthe web community

ProblemsOEM pricing (current price of $5K/server)

Lecture 25 - University of Massachusetts Amherst · 2010. 12. 7. · 4 HTML and script are returned to browser 5 Web browser processes script to create HTML Tom Horton Alfred C. Weaver

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