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PHP Training: Module 1

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The document provides an overview of PHP and its capabilities compared to other web technologies. It discusses how PHP allows for dynamic content and user interactivity on websites, unlike static HTML. It also summarizes HTTP and the client-server model, and how PHP integrates as a common gateway interface (CGI) to enable server-side scripting. Key topics covered include the history of HTML/XHTML, HTTP request/response formats, and how PHP addresses limitations of static websites by running on the server-side.

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PHP – Module 1 Hussain Fakhruddin [email_address]
Agenda HTML/XHTML and HTTP Basics Review PHP and the Web Server Architecture Model Overview of PHP Capabilities CGI vs. Shared Object Model
HTML/XHTML and HTTP Basics Review HTML/XHTML – a language that every browser knows. HTTP – a protocol that every machine uses to talk with others.
HTML – Hyper Text Markup Language Basically designed and used as a common language to retrieve documents from web. More features (called as tags) added later. Now is replaced by dynamic languages (like PHP) in some places. Tags are basically used to organize contents of document.
XHTML – eXtended HTML A strict format of HTML Each starting tag must have ending tag. There are strict rules to be followed. e.g. In HTML <br> is allowed, but in XHTML it must be <BR/> Similarly: HTML XHTML <p> <P/> <li>... <LI>......</LI>
Web Server Architecture Model Client server model. Like a query session after a lecture! Clients send request, server sends reply to the requested. Our web browser is typical client, which formats HTTP (or HTTPS etc.) request and sends to a server. A server (e.g. Apache on www.sachinism.com ) formats response and sends back to the browser.
Working of Internet
A representation of client-server talk - 1 Client Server To Server, “Can you please give me index.htm?”
A representation of client-server talk - 2 Client Server To Client, “ Sure, here it is...” Contents of index.htm
A representation of client-server talk - 3 Client Server Wow... I am lucky to get index.htm so fast! Actual webpage, that can be displayed on browser
HTTP – HyperText Transfer Protocol Protocol for talks between Client and server for Websites. Default Port no. 80 Simple, text based protocol Request – Reply model Stateless Two most frequently used methods (operations) – GET and POST
HTTP Format Request Format Request line (e.g. GET /images/logo.gif HTTP/1.1) Headers (e.g. Accept-Language: en) An optional message body
HTTP Request in details Request method – e.g. GET / POST / PUT URL – where to send the request HTTP version – e.g. 1.1 POST /my_dir/my_sub_dir/my_file.htm HTTP/1.1
Request methods -1 HEAD Request only headers for an GET request, not actual resource / data. Used to retrieve meta-data. GET Request actual resource. Used as a method to send data along with request. This data is shown on address bar of a browser! POST Request actual resource. Most common method used to send data to be processed by the resource. This data is not shown in address bar, is inserted in request body.
Request methods -2 PUT Uploads a resource. DELETE Removes / Delets a specified resource. TRACE Redisplays a request, to check if some server in midway to the destination has changed any value. OPTIONS Returns methods supported by the server's specific resource. Used to check server's functionality / support. CONNECT Converts the request connection to a transparent TCP/IP tunnel. Not much secure.
HTTP Format Response form Status line Headers An optional message body
HTTP Response Status Line HTTP Version Status code of 3 digits Status description
HTTP Response – Status details 200 OK Request successful 302 Moved Permanently URL is no longer used by server 404 Page not found Requested document / resource not found 500 Internal server error Some error on server
Request / Response Headers Exchange of information between client and server. Each line : Header name + value Classification of header lines: General header Request header Response header Entity header
General Header Can be present in both – request and response. Header Description Cache-control Information about caching Connection Connection should be either closed or kept open. Date Current date
Request Header Specific to request messages. Header Description Accept Message format that is supported by client Accept-language Language that client accept Host Host and port number of client If-modified-since Send the document if newer than specified date If-unmodified-since Send the document if older than specified date
Response Header Specific to response message Header Description Age Age of document Retry-after Date after which server is available Sever Sever name + port
Entity Header Mostly used in response message Header Description Content-encoding Encoding scheme Content-language Language Content-length Length Last-modified Last modification date and time Content-type Type of media document
HTTP Example Request GET http://www.sachinism.com/index.htm HTTP/1.0 Accept: text/html Accept: image/jpeg Response HTTP/1.0 200 OK Date: Thu, 20-Feb-08 09.00.00 GMT Server: Challenger MIME-version: 1.0 Content-length: 2048 << HTML Body >>
A representation of client-server talk - 1 Request GET http://www.sachinism.com/index.htm HTTP/1.0 Accept: text/html Accept: image/jpeg Client Server To Server, “Can you please give me index.htm?”
A representation of client-server talk - 2 Response HTTP/1.0 200 OK Date: Thu, 20-Feb-08 09.00.00 GMT Server: Challenger MIME-version: 1.0 Content-length: 2048 <<HTML Body >> Client Server To Client, “ Sure, here it is...” Contents of index.htm
A representation of client-server talk - 3 Client Server Wow... I am lucky to get index.htm so fast! Actual webpage, that can be displayed on browser
CGI - The Common Gateway Interface CGI is a standard protocol for interfacing external application software with an information server, commonly a web server. an information server responds to requests(in the case of web servers, requests from client web browsers) Each time a request is received, the server analyzes what the request asks for, and returns the appropriate output.
 
CGI The two simplest ways, for the server, of doing this are the following: 1) If the request identifies a file stored on disk, return the contents of that file; 2) If the request identifies an executable command and possibly arguments, run the command and return its output
 
PHP PHP Hyper Processor or Personal Hypertext Processor A server side programming language Emerged as leading language in server side application development since a decade! HTML can simply display data (static) whereas PHP can be executed on server and the result is displayed on client (Dynamic) - will discuss later in this session
Why use PHP? 1)PHP is a server-side interpreter which is Open Source and free; 2)So is a growing number of PHP web applications; 3)PHP provides familiar syntax to C, Perl and Java developers; 4)PHP has fast connections to popular databases; 5)PHP has fast native connections to the Open Source MySQL database;
Why use PHP? 6)PHP runs reliably on Windows, Linux and Mac servers and clients; 7)PHP web pages run reliably on all the popular browsers; 8)PHP's associative arrays are very useful for UI and database apps; 9)PHP's object oriented classes are easy to understand; 10)PHP has been very promiscuous-linking to PDF, SWF, XML, Java, etc, etc.
Role of PHP - advantage Everything goes personalize I.E. User settings, look and feel, some private data etc. Provides user interactivity Allows to create own web applications that can be executed remotely! Examples : any website provides login and thereafter services, live cricket scores on sachinism.com
HTML/JS VS PHP JavaScript = ClientSide; PHP = ServerSide With php you can have the remote time, with js you can have user time... with php the source is not lookable in the source code with js the source can be see in the source code of the page. Javascript NOT EQUAL TO PHP
Recap
Summary Internet era began with static webpages written in HTML, which required strict rules – created XHTML. Every web based application (essentially webpages / websites) are communicating on HTTP which follow specific format. User requests something to server and server sends back relevant data – implements client server architecture. Later on, server side programming languages like PHP adds user interactivity, personalisation of websites.
Whats next? Starting up with PHP Obtaining, Installing and Configuring PHP Obtaining PHP Source Code Installing PHP from Binary Packages Dynamic Extensions, Checking Install with phpinfo() Function.

More Related Content

PHP Training: Module 1

  • 1. PHP – Module 1 Hussain Fakhruddin [email_address]
  • 2. Agenda HTML/XHTML and HTTP Basics Review PHP and the Web Server Architecture Model Overview of PHP Capabilities CGI vs. Shared Object Model
  • 3. HTML/XHTML and HTTP Basics Review HTML/XHTML – a language that every browser knows. HTTP – a protocol that every machine uses to talk with others.
  • 4. HTML – Hyper Text Markup Language Basically designed and used as a common language to retrieve documents from web. More features (called as tags) added later. Now is replaced by dynamic languages (like PHP) in some places. Tags are basically used to organize contents of document.
  • 5. XHTML – eXtended HTML A strict format of HTML Each starting tag must have ending tag. There are strict rules to be followed. e.g. In HTML <br> is allowed, but in XHTML it must be <BR/> Similarly: HTML XHTML <p> <P/> <li>... <LI>......</LI>
  • 6. Web Server Architecture Model Client server model. Like a query session after a lecture! Clients send request, server sends reply to the requested. Our web browser is typical client, which formats HTTP (or HTTPS etc.) request and sends to a server. A server (e.g. Apache on www.sachinism.com ) formats response and sends back to the browser.
  • 8. A representation of client-server talk - 1 Client Server To Server, “Can you please give me index.htm?”
  • 9. A representation of client-server talk - 2 Client Server To Client, “ Sure, here it is...” Contents of index.htm
  • 10. A representation of client-server talk - 3 Client Server Wow... I am lucky to get index.htm so fast! Actual webpage, that can be displayed on browser
  • 11. HTTP – HyperText Transfer Protocol Protocol for talks between Client and server for Websites. Default Port no. 80 Simple, text based protocol Request – Reply model Stateless Two most frequently used methods (operations) – GET and POST
  • 12. HTTP Format Request Format Request line (e.g. GET /images/logo.gif HTTP/1.1) Headers (e.g. Accept-Language: en) An optional message body
  • 13. HTTP Request in details Request method – e.g. GET / POST / PUT URL – where to send the request HTTP version – e.g. 1.1 POST /my_dir/my_sub_dir/my_file.htm HTTP/1.1
  • 14. Request methods -1 HEAD Request only headers for an GET request, not actual resource / data. Used to retrieve meta-data. GET Request actual resource. Used as a method to send data along with request. This data is shown on address bar of a browser! POST Request actual resource. Most common method used to send data to be processed by the resource. This data is not shown in address bar, is inserted in request body.
  • 15. Request methods -2 PUT Uploads a resource. DELETE Removes / Delets a specified resource. TRACE Redisplays a request, to check if some server in midway to the destination has changed any value. OPTIONS Returns methods supported by the server's specific resource. Used to check server's functionality / support. CONNECT Converts the request connection to a transparent TCP/IP tunnel. Not much secure.
  • 16. HTTP Format Response form Status line Headers An optional message body
  • 17. HTTP Response Status Line HTTP Version Status code of 3 digits Status description
  • 18. HTTP Response – Status details 200 OK Request successful 302 Moved Permanently URL is no longer used by server 404 Page not found Requested document / resource not found 500 Internal server error Some error on server
  • 19. Request / Response Headers Exchange of information between client and server. Each line : Header name + value Classification of header lines: General header Request header Response header Entity header
  • 20. General Header Can be present in both – request and response. Header Description Cache-control Information about caching Connection Connection should be either closed or kept open. Date Current date
  • 21. Request Header Specific to request messages. Header Description Accept Message format that is supported by client Accept-language Language that client accept Host Host and port number of client If-modified-since Send the document if newer than specified date If-unmodified-since Send the document if older than specified date
  • 22. Response Header Specific to response message Header Description Age Age of document Retry-after Date after which server is available Sever Sever name + port
  • 23. Entity Header Mostly used in response message Header Description Content-encoding Encoding scheme Content-language Language Content-length Length Last-modified Last modification date and time Content-type Type of media document
  • 24. HTTP Example Request GET http://www.sachinism.com/index.htm HTTP/1.0 Accept: text/html Accept: image/jpeg Response HTTP/1.0 200 OK Date: Thu, 20-Feb-08 09.00.00 GMT Server: Challenger MIME-version: 1.0 Content-length: 2048 << HTML Body >>
  • 25. A representation of client-server talk - 1 Request GET http://www.sachinism.com/index.htm HTTP/1.0 Accept: text/html Accept: image/jpeg Client Server To Server, “Can you please give me index.htm?”
  • 26. A representation of client-server talk - 2 Response HTTP/1.0 200 OK Date: Thu, 20-Feb-08 09.00.00 GMT Server: Challenger MIME-version: 1.0 Content-length: 2048 <<HTML Body >> Client Server To Client, “ Sure, here it is...” Contents of index.htm
  • 27. A representation of client-server talk - 3 Client Server Wow... I am lucky to get index.htm so fast! Actual webpage, that can be displayed on browser
  • 28. CGI - The Common Gateway Interface CGI is a standard protocol for interfacing external application software with an information server, commonly a web server. an information server responds to requests(in the case of web servers, requests from client web browsers) Each time a request is received, the server analyzes what the request asks for, and returns the appropriate output.
  • 29.  
  • 30. CGI The two simplest ways, for the server, of doing this are the following: 1) If the request identifies a file stored on disk, return the contents of that file; 2) If the request identifies an executable command and possibly arguments, run the command and return its output
  • 31.  
  • 32. PHP PHP Hyper Processor or Personal Hypertext Processor A server side programming language Emerged as leading language in server side application development since a decade! HTML can simply display data (static) whereas PHP can be executed on server and the result is displayed on client (Dynamic) - will discuss later in this session
  • 33. Why use PHP? 1)PHP is a server-side interpreter which is Open Source and free; 2)So is a growing number of PHP web applications; 3)PHP provides familiar syntax to C, Perl and Java developers; 4)PHP has fast connections to popular databases; 5)PHP has fast native connections to the Open Source MySQL database;
  • 34. Why use PHP? 6)PHP runs reliably on Windows, Linux and Mac servers and clients; 7)PHP web pages run reliably on all the popular browsers; 8)PHP's associative arrays are very useful for UI and database apps; 9)PHP's object oriented classes are easy to understand; 10)PHP has been very promiscuous-linking to PDF, SWF, XML, Java, etc, etc.
  • 35. Role of PHP - advantage Everything goes personalize I.E. User settings, look and feel, some private data etc. Provides user interactivity Allows to create own web applications that can be executed remotely! Examples : any website provides login and thereafter services, live cricket scores on sachinism.com
  • 36. HTML/JS VS PHP JavaScript = ClientSide; PHP = ServerSide With php you can have the remote time, with js you can have user time... with php the source is not lookable in the source code with js the source can be see in the source code of the page. Javascript NOT EQUAL TO PHP
  • 37. Recap
  • 38. Summary Internet era began with static webpages written in HTML, which required strict rules – created XHTML. Every web based application (essentially webpages / websites) are communicating on HTTP which follow specific format. User requests something to server and server sends back relevant data – implements client server architecture. Later on, server side programming languages like PHP adds user interactivity, personalisation of websites.
  • 39. Whats next? Starting up with PHP Obtaining, Installing and Configuring PHP Obtaining PHP Source Code Installing PHP from Binary Packages Dynamic Extensions, Checking Install with phpinfo() Function.