Simple PHP application A simple application We are

Simple PHP application

A simple application • We are going to develop a simple PHP application with a Web interface. • The user enters two numbers and the application returns the two multiplied to together • Start

UML Interaction Diagram • Interaction diagrams describe the communication between objects, but we will use them to describe interation between programs even if they are not objects

• Simple interaction diagram • Simple example and explanation • Ref to UML

User-script interaction Click link Browser page Web server multiply. php PHP processor get form. htm Locate file Enter data Display form. htm Calculate button get multiply. php? x=5&y=6 Locate file and run as PHP x=5 y=6 5 * 6 = 30 HTML MIME Read output Display generated HTML run script “ 5 * 6 = 30”

User-browser interaction Browser Click link page Enter data Display form. htm Calculate button Read output Display generated HTML

User – Browser interaction • User locates desired link <a href=form. htm> Multiply numbers</a> • • • Browser retrieves the form from the server Form is displayed User fills in the fields on the form User clicks submit button Magic stuff happens • User reads the result and goes back to the form to change the values in the form

form. htm <!-this is not XHTML standard because it lacks headers but it does have all attribute values in quotes and all tags are terminated --> <form method="get" action="multiply. php"> x = <input type=text name="x" size="5"/> y = <input type=text name="y" size="5"/> <input type="submit" value="Calculate"/> </form>

Browser-Server interaction Browser Click button Web server get multiply. php? x=5&y=6 Locate file and run as PHP 5 * 6 = 30

Browser-Server interaction • Parameters passed as data couplets (name/value pairs) either – Attached to URL (and visible to user in the address line) • Values must be URL-Encoded – space to + – punctuation to %hex e. g. ? to %3 f • METHOD=GET in an HTML Form – appended to the ACTION URL • Explicitly added to the base URL e. g. – <a href=“multiply. php? x=5&y=6”>5 * 6</a> – A separate document (invisible to user) • METHOD=POST in an HTML Form • Result passed back in a MIME wrapper – MIME tells browser what kind of file it is (HTML, JPEG, XML, Flash. . ) • Content-type: image/jpeg

Server-script interaction Web server multiply. php get multiply. php? x=5&y=6 Locate file and run as PHP x=5 y=6 run script “ 5 * 6 = 30”

User-script interaction Click link Browser page Web server multiply. php PHP processor get form. htm Locate file Enter data Display form. htm Calculate button get multiply. php? x=5&y=6 Locate file and run as PHP x=5 y=6 5 * 6 = 30 HTML MIME Read output Display generated HTML run script “ 5 * 6 = 30”

form. htm <!-this is not XHTML standard because it lacks headers but it does have all attribute values in quotes and all tags are terminated --> <form method="get" action="multiply. php"> x = <input type=text name="x" size="5"/> y = <input type=text name="y" size="5"/> <input type="submit" value="Calculate"/> </form>

Browser-Server interaction Browser Web server Click button get multiply. php? x=5&y=6 Locate file and run as PHP 5 * 6 = 30 HTML MIME

URL • Relative URL – multiply. php? x=5&y=6 • Absolute URL – http: //localhost/UFIE 8 V/l 3 php/multiply. php? x=5&y=6 (my Home machine running IIS) – http: //stocks. uwe. ac. uk/~cjwallac/UFIE 8 V/l 3 php/multiply. php? x=5&y=6 (the development server) – http: //www. uwe. ac. uk/~cjwallac/UFIE 8 V/l 3 php/multiply. p hp? x=5&y=6 (the public production server)

Server-script interaction Web server multiply. php PHP processor get multiply. php? x=5&y=6 Locate file and run as PHP x=5 y=6 run script “ 5 * 6 = 30”

Server-PHP interaction • Parameters – GET and POST Parameters available as • variables of the same name $x, $y (deprecated but used in my code ) • in an array $_GET[‘x’] • depends on the setup – Parameter values are URL-Decoded • Implicit Parameters – In addition to the user-defined parameters, other data is available about the client and about the server – $PHP_SELF is the program name – $HTTP_USER_AGENT is the browser • Reply – HTML goes through to output – <? php … ? > script is executed as PHP • Print or echo statements add to output – All output returned to Server – Other kinds of output (JPEG, GIF. . ) require different headers to be output

Multiply. php script <? php /* function: to multiply the two input numbers and display the result input: x, y : numbers author: Chris Wallace 9 Oct 204 */ // calculate the result // no typing or declaring new variable // also implicit conversion of string to number $prod = $x * $y; // values of variables interpolated into the string print "$x * $y = $prod"; ? >

The generated HTML • 5 * 6 = 30 • This simple text is not XHTML compliant of course. • HTML to provide a readable page can be added around the PHP • <a href=multiply 2. php? x=5&y=6>5 * 6</a> • Note that we have added the name/value pairs to the URL – not very useful here obviously. • some pairs can be in the action URL of a form, some in input fields • The script multiply 2. php includes the original PHP script within an HTML page

Multiply 2. php Program composition with ‘require’ <html> <title>PHP introduction - multiply script</title> </head> <body> <img src="cems-banner. gif"> <h 1>PHP introduction</h 1> <table><tr><td><img src="multiply. jpg"></td><td width="5%"</td><font color="red" size="+4"> <? php include "multiply. php“; ? > </font></td><tr></table> </body> </html>

‘Sticky Forms’ • Poor interface -user must to go back to original form to change the data and recalculate. • Key idea: – Combine form and calculator into one script – Do calculation (if required) first – Put inputs as defaults in form • Simple combination of form and script – <a href=multiply 3. php> Calculate Product </a>

multiply 3. php Combined form and calculator <? php // first compute the output, but only if data has been input if( isset($calc)) { // data was submitted $prod = $x * $y; } else { // set defaults $x=0; $y=0; $prod=0; } ? > <form method="get" action="<? php print $PHP_SELF; ? >"> x = <input type=text name="x" size="5" value="<? php print $x? >"/> y= <input type=text name="y" size="5" value="<? php print $y? >"/> x * y = <? php print $prod ? > <br/><input type="submit" name="calc" value="Calculate"/> </form>

Initial Form <form method="get" action=“scripts/multiply 3. php"> x = <input type=text name="x" size="5" value="0"/> y= <input type=text name="y" size="5" value="0"/> x * y = 0<br/><input type="submit" name="calc" value="Calculate"/> </form>

Form with Entered Values <form method="get" action=“scripts/multiply 3. php"> x = <input type=text name="x" size="5" value="654321"/> y= <input type=text name="y" size="5" value="9"/> x * y = 5888889<br/><input type="submit" name="calc" value="Calculate"/> </form>

Forms processing • Interface and presentation can be easily improved – <a href=multiply 4. php> Calculate Product </a> • Script can do validation and add error messages to the form where fields are missing or invalid. • Where to do the processing? : – on Client in Javascript – on Server in PHP or Java • What factors do you need to consider to decide?

SMS version • Now nearly the same application with an SMS presentation layer. • For variety, I’ve generalised to allow any number of numbers to be multiplied together • Text – MUL num 1 num 2 num 3 … – To: 076 24 80 37 59 • Eg. – MUL 34 56 78 • Reply – 34 x 56 x 78 = 148512

SMS to script interface • Script ‘plugs’ into SMS server • Must obey the protocol: – Parameters • Text • From • Code – Reply text: • Reply: <message to send back> • Entry required in routing file: – MUL http: //www. cems. uwe. ac. uk/~cjwallac/ISD 3/sms mult. php

smsmult. php <? php $text=trim($text); // to remove trailing whitespace $nums = split(" +", $text); // split the string apart on spaces // + means 1 or more occurances $prod=1; foreach ($nums as $number){ $prod=$prod*$number; // accumulate the product } $numlist = join(" x ", $nums); // join the numbers with ' x ' print "Reply: $numlist = $prod"; ? >