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Other Web Application Development Technologies. PHP.

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Presentation on theme: "Other Web Application Development Technologies. PHP."— Presentation transcript:

1 Other Web Application Development Technologies


3 Personal Home Pages originally; now –PHP: Hypertext Preprocessor PHP is a server-side scripting language, like ASP –PHP scripts are executed on the server language for creating HTML content –normally runs as a server-side scripting language –command line scripting possible from PHP4.2 –client-side GUI applications using PHP-GTK Also generates other formats –PDF, GIF, JPEG, PNG, Flash

4 PHP free, open source technology –free to download and use extensive libraries of PHP code modules runs on all major operating systems –develop in Windows and serve on a Unix platform runs with all major web servers (Apache, IIS, iPlanet) good database integration –MySQL, Oracle, ODBC databases, PostgreSQL, Sybase combined with MySQL offers a cross-platform, open source, efficient solution

5 What is a PHP File? PHP files can contain –text, –HTML tags –and scripts PHP files are returned to the browser as plain HTML PHP files have a file extension of ".php", ".php3", or ".phtml"

6 PHP example … PHP Hello World Example

7 PHP architecture

8 PHP/Web Server Architecture web server layer –handles http requests –passes data to PHP via SAPI TSRM Thread-Safe Resource Management PHP language core –many of the non-optional core features of PHP PHP API (available to core and PHP extensions) PHP extensions –PHP comes with a skeleton extension framework Zend parsing engine –runtime compiler –executer

9 PHP/Web Server Architecture web sever (Apache, IIS, etc..) Server Abstraction API (SAPI) TSRM Zend Engine PHP Core PHP extensions TSRM PHP API

10 input client HTML page PHP page PHP Zend parsing engine web server data http request output HTML http response PHP and http

11 form processing example Ice Cream Parlour Flavour : vanilla chocolate Scoops :

12 form processing example Ice Cream Response Thank you for your order <?php $flavour = $_POST [flavour]; $scoops = $_POST [scoops]; echo $scoops scoops of $flavour coming right up!; ?>

13 self processing PHP page <?php if(!empty($_POST[name])) { echo Greetings, {$_POST[name]}; } else {?> METHOD=POST> Enter your Name:

14 control of http response PHP sets standard headers by default –response status line –date, document length –other headers added by web server header () function allows other headers to be set –header (content-type: text/plain); header must be used before any html generated (including leading tag)

15 cookies $_COOKIE associative array used for input setcookie () function sets cookie headers in the http response –setcookie(name, value, expiration); –$var_name = $_COOKIE[name']; //retrieves cookie <?php $accesses = $_COOKIE [accesses]; setcookie (accesses, ++$accesses); ?> must be used before html content

16 sessions PHP provides automatic session handling sessions set up using start_session() command –start_session() must appear at the start of the PHP document registers the user's session with the server user data stored in the $_SESSION associative array – set: $_SESSION[name] = value ; –retrieve: $var_name= $_SESSION[name] –free up specific variable: unset($_SESSION['views']); –destroy: session_destroy();

17 simple hit counter <?php session_start(); // start up your PHP session! if(isset($_SESSION['views'])) { $_SESSION['views'] = $_SESSION['views']+ 1; //retrieve session variable }else {$_SESSION['views'] = 1; } //set session variable echo "views = ". $_SESSION['views']; ?>

18 OOP in PHP Limited support in PHP <5 Much better support in PHP >=5 Simpler than Java OOP class SomeClass { function func() { …. } SomeClass s = new someClass(); s->func();

19 PHP and XML

20 PHP has strong text processing functionality –comprehensive string manipulation –strong regular expressions inherited or imported from Perl full set of filehandling functions for file I/O XML data files can be created/manipulated programmatically using text processing approaches

21 PHP and XML DOM –DOM processing from PHP 4.3 –DOM extension part of PHP 5 core XSLT –libxslt extension in PHP 5 –A separate XSLT extension available from Sablotron C library (different API) SAX –based on libxml2 library in PHP 5

22 PHP and XSLT libxslt extension in PHP 5 <?php // Load XML $xml = new DomDocument; $xml->load(cdcatalog.xml); // Load the XSL $xsl = new DomDocument; $xsl->load (cdcatalog.xsl ); // configure xslt processor $xslt = new Xsltprocessor; $xslt->importStylesheet($xsl); // Transform echo $xslt->transformToXML($xml); ?>

23 PHP and XSLT <?php $processor = xslt_create (); $result = xslt_process($processor,source.xml,transform.xml); if(!$result) echo xslt_error ($processor); xslt_free ($processor); echo $result ; ?>

24 events-based XML programming PHP has an event-based XML parser based on libxml2 library –SAX parser –replaces old non-SAX Expat library parser calls handler functions as events occur you write the event handler functions

25 PHP strengths and weaknesses

26 PHP strengths free, open-source product –flexible –extensible easy to implement –builds onto most browsers on most platforms –familiar, flexible and powerful syntax with occasional weirdness thrown in good database connectivity –technology of choice for low-end web-DB system

27 PHP weaknesses XML support –some non-standard features still in PHP5 slow because of runtime compilation then execution –derives from CGI script origins –PHP accelerator reduces this limited separation of coding from HTML –no equivalent of JSP custom tags –some open source versions emerging see extensibility limited by cumbersome C-based architecture –this is improving with later versions

28 PHP web application frameworks Frameworks are now emerging for PHP Cake –Started in 2005 - Latest release 22 October2007 –Modelled on ruby for rails. Implements MVC –growing developer community, growing functionality – Symfony –Very recent but stems from older projects. Implements MVC –Symfony 1.4 planned for Nov. 09 –established development community. – Zend Framework (June 2006, currently v.1.0.3) –growing community of developers –provide components for the MVC –

29 PHP web application frameworks software framework that support the development of dynamic websites Typical functionality –CRUD (database interaction) make database interfacing easier for the user –M-V-C architecture Implement the MVC design pattern –Access control lists come with authentication and authorization frameworks –View helpers - AJAX, JavaScript, etc… –Session & cookie management –Standard application components/templates Promote code reuse Provide object-oriented design environment

30 Active Server Pages (ASP)

31 Microsoft-based server-side processing technology ASP provides a server-side scripting environment. This includes: Read information from an HTTP request. Customize an HTTP response. Interact with Databases. Support complex middleware.

32 Active Server Pages (ASP) are processed in response to a client request ------ server-side scripting are processed by an ActiveX component ------ a scripting engine.asphave the file extension.asp contain HTML tags and scripting code VBScript is the most widely used language (although you can use JavaScript, other.NET languages)

33 The ASP Architecture ASP.DLL

34 A user makes an http request for an ASP page. The.asp extension tells the Web server that the page contains server script (executable code) that it should process before returning the page to the browser. The server passes the ASP to the scripting engine The scripting engine executes ASP commands as it encounters them After execution of the server scripts, all code is stripped out of the page. The pure HTML page is sent in the http reponse.

35 A Simple ASP Example A Simple ASP Example

36 A Simple ASP Example Simple ASP Example


38 ASP Built-in Objects Request Response Session Application Server ObjectContext

39 ASP Built-in Objects Request –Retrieves the values that the browser passes to the server during an HTTP request. Response –Controls what information is sent to a browser in the HTTP response message.

40 ASP Built-in Objects Session –Used to manage and store information about a particular user session. Application –Used to manage and store information about the Web application.

41 ASP Built-in Objects Server –Provides access to resources that reside on a server. ObjectContext –Used to commit or abort a transaction managed by Microsoft Transaction Server (MTS) for ASP pages that run in a transaction.

42 ASP Built-in Objects Retrieve information passed from the browser to the server using the Request object. Send output to the browser using the Response object. Store information for a specific user using the Session object. Share information among all users of your application using the Application object. Work with the properties and methods of components on the server using the Server object.

43 Request Object Collections ClientCertificate Cookies Form QueryString ServerVariables

44 Form Collection The Form collection contains the values of each standard HTML control that has a NAME attribute. When a user submits a form with the POST method, you can read the values of the controls by using the Form collection. The Form collection of the Request object can be used to extract information from the body of an HTTP request message.

45 Form Collection Name: Favourite Flavour: Mint Vanilla Coffee

46 Form Collection icecream.asp Request.Form("name") Request.Form(flavour") or <% For Each Item in Request.Form 'code to display Item here Next %>

47 ASP on Alternative Platforms Chili!ASP by Chili!Soft (Expensive to buy!) Windows –IIS, Apache, Netscape Enterprise & FastTrack, OReilly WebSite Pro Solaris –Apache, Netscape Enterprise & FastTrack Linux: Apache IBM AIX: Apache, Netscape Enterprise & FastTrack, IBM HTTP Server, Lotus Domino Go HP UX –Apache, Netscape Enterprise

48 ASP on Alternative Platforms Instant ASP (iASP) by Halcyon Software cheaper written in Java as a Servelet, so runs with Apache/Tomcat and many other servers allows mix of ASP and JSP –better range of functionality –may run slow for high volume applications

49 ASP Strengths implements M-V-C code embedded in the HTML –separation of concerns no compiling - stays resident in memory no complex interfacing - method calls suitable for high-end web applications standard components –re-use –eases programming effort

50 ASP weaknesses difficult to port between platforms steep learning curve for full functionality –less suitable for low-end web apps multiplicity of.NET languages –diffuse coding options –can leave legacy problems

51 ColdFusion

52 Technology for building dynamic web applications provides powerful markup reducing need for programming skills designed for RAD: abstracts many low- level tasks e.g. connection to a database

53 ColdFusion runs on all major platforms compatible with all major browsers runs in CGI mode or as an embedded process runs on Apache, IIS, iPlanet ColdFusion applications are portable across platforms with very minor differences

54 History of ColdFusion developed by Allaire software –first version 1995 - only 30 language elements –strongly tag-based, supplemented by functions Allaire merged with Macromedia in 2001 –MacroMedia ColdFusion –ColdFusion MX ColdFusion MX 6.1 (2004) –80 tags, 255 functions

55 use and availability Widely used for medium to large scale web apps Large developer community Not free, not open source –ColdFusion MX Standard £929 Windows, Linux –ColdFusion MX Enterprise £4289 Windows, Linux, Solaris, HP-UX, AIX –30-day free trial version (limited functionality)

56 ColdFusion Basics

57 ColdFusion Markup Language tag-based language (CFML) mixed with HTML, JavaScript/VBScript in a template CFML used to dynamically construct content CFML processed by ColdFusion Application Server on the server side

58 client HTML page CFML template ColdFusion Application Server web server entity data http request input output HTML http response

59 ColdFusion templates CFML tags embedded in HTML –Can produce pure CFML pages Tag Syntax – content –or trailing / optional –Attributes are literals or expressions –Tags controlled by attributes and/or content

60 Example 1 Writing output x = #x# y = #y# x * y = #xy#

61 Example 2 Todays date is #DateFormat (Now (),dd/mm/yy)# CFML tag closing CFML tag

62 Example 3 <CFMAIL FROM = "" TO = "" SUBJECT = "Assessed Lab" SERVER = "" > Have a Merry Christmas.

63 ColdFusion Web Application Framework

64 web application a group of templates forming a cohesive application –maintain state –utilise constants –multi-threading –error and exception handling –security controlled through application template

65 Application.cfm template reserved template name template placed in root directory of the web application –executed before every request may be supplemented by OnRequestEnd.cfm template –executed after every web request

66 processing Application templates ColdFusion template requested ColdFusion searches template directory for an Application.cfm template –ColdFusion processes Application.cfm template then requested template –OnRequestEnd.cfm template processed if it exists

67 template request process client Server myTemplate application template onREquestEnd request response

68 function of Application.cfm maintains state –create Application, Client and Session variables set application constants –data-source names, source directories, style elements handle errors provide security services –user authentication –entitlements

69 ColdFusion strengths and weaknesses

70 strengths tag-oriented programming for web developers –good support for custom tags and extensions full functionality to support medium to high end web systems supports MVC strong support for thread-safe transactions excellent database connectivity implemented on all major platforms

71 weaknesses expensive compared with other technologies not open source highly redundant syntax –leads to inconsistent development idiosyncratic language structure –limited code re-use on or from other platforms non-standard and limited XML support

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