Slide 1

Download Report

Transcript Slide 1 

Website Development with PHP and
MySQL
Saving Data
What you will achieve this week!
•Submitting data to the server
•Saving data on a server using files
Reminder of the general process
: Customer
browser
web server
scripting
language
database
request service
access page
interpret
set data
get data
get data
return html
present html
What can we do with Forms?
• Standard HTML tags which:
– Collect user input
– Specify where to send the input
– Specify how to send the input to be processed
• HTML tags simply provide an interface to allow
user interaction
• Input is handled by a separate script or program:
– On the server
• e.g. via PHP, ASP, CGI etc.
– In the browser
• e.g. JavaScript
More Input Types
• Radio buttons
Choose ONE of the following:
<input type="radio" name="choice" value="A"
checked="checked" />A
<input type="radio" name="choice" value="B" />B
<input type="radio" name="choice" value="C" />C
• Check boxes
Choose ANY, ALL or NONE of the following:
<input type="checkbox" name="A" value="yes"
checked="checked" />A
<input type="checkbox" name="B" value="yes" />B
<input type="checkbox" name="C" value="yes" />C
Even More Input Types
• Drop-down menus
• Text area
Secret Stuff?
• Passwords
<p>
Care to give us a password?
<input type="password" name="my_password" />
</p>
• Hidden fields
<p>
<input type="hidden" name="my_secret"
value="hello" />
</p>
Submit and Reset Buttons
• The submit button sends form data to be
processed
<p>
<input type="submit" value="submit" />
</p>
• The reset button returns fields to original
state
<p>
<input type="reset" value="reset" />
</p>
How to get data from a form to a
program
• Specify how to send the form data
– Specified with the method attribute
– GET or POST
<form method="get"> or <form method="post">
– If not specified – default is GET
• Specify where to send the form data
– Specified by the action attribute
– Usually a script or program – can be local or full URL
<form method="get" action="formscript.php">
<form method="get" action="http://www.hud.ac.uk/
resources/scripts/formscript.php">
The GET Method
• Client makes an HTTP GET request for a script
– Form data is appended to the script URL as name/value
pairs – a querystring
– The script has access to values sent in the querystring
• In addition
– Input data can be hard-coded directly in a URL
• No need for a form
– Results can be bookmarked
The POST Method
• Client makes an HTTP POST request for a
script
– Form data is sent as name/value pairs in the
body of the request
• In addition
– Useful for large amounts of data
• Browser may truncate a long querystring
– Data is not visible in the URL
– Results cannot be bookmarked
Form Processing Scripts
• Scripts are run by the web server via a web server
application
– CGI, PHP, ASP, ColdFusion etc…
• Scripts can be written in almost any language
– PHP, VBScript, Perl, CFML etc…
– Language may depend on web server application(s)
• Scripts receive form input from via GET or POST
– Process input based on instructions in the script
•
•
•
•
Create an e-mail message
Perform database query
Write information to a file
Generate a web page
Form Processing
User submits
form to web
server
Name: Arnold
Comments:
“Nice website!"
Web server passes
form data to
processing script
Send
email?
Return a
web
page?
<html>
...
</html>
Submitting data to server through
forms
Simple examples that echo the
submitted data back
simpleTextBox.htm
: customer
webServer
echoName.php
enter name
submit
submit(echoName.php3)
open($name)
display
<html>
<head></head>
a PHP page to process the form
<body>
<form method="POST" action="echoName.php">
<p>Name<input type="text" name="name" size="20"></p>
<p><input type="submit" value="Submit" name="B1">
<input type="reset" value="Reset" name="B2"></p>
</form>
</body>
</html>
a variable to pass to the PHP page
test
echoName.php
calculator.htm
: customer
webServer
calculatorResult.php
enter numbers
submit
submit(calculatorResult.php3) open($num1,$num2)
display
<html>
<head></head>
<body>
<form method="POST" action="calculatorResult.php">
<p>Number 1<input type="text" name="num1" size="20"></p>
<p>Number 2<input type="text" name="num2" size="20"></p>
<p><input type="submit" value="Submit" name="B1">
<input type="reset" value="Reset" name="B2"></p>
</form>
</body>
</html>
test
calculatorResult.php
Saving data
using files
: customer
nameAddress.htm
webServer
saveAddress.php
nameAddress
enter name
enter address
submit
submit(saveAddress.php)
open($name,$address)
open
write
close
display
int fopen (string filename, string mode)
mode may be any of the following:
'r' - Open for reading only; place the file pointer at the beginning of the file.
'r+' - Open for reading and writing; place the file pointer at the beginning of the
file.
'w' - Open for writing only; place the file pointer at the beginning of the file and
truncate the file to zero length. If the file does not exist, attempt to create it.
'w+' - Open for reading and writing; place the file pointer at the beginning of the
file and truncate the file to zero length. If the file does not exist, attempt to create
it.
'a' - Open for writing only; place the file pointer at the end of the file. If the file
does not exist, attempt to create it.
'a+' - Open for reading and writing; place the file pointer at the end of the file. If
the file does not exist, attempt to create it.
string sprintf (string format [, mixed args...])
The format string is composed of zero or more directives: ordinary characters
(excluding %) that are copied directly to the result, and conversion specifications,
each of which results in fetching its own parameter.
b - the argument is treated as an integer, and presented as a binary number.
c - the argument is treated as an integer, and presented as the character with that
ASCII value.
d - the argument is treated as an integer, and presented as a decimal number.
f - the argument is treated as a double, and presented as a floating-point number.
o - the argument is treated as an integer, and presented as an octal number.
s - the argument is treated as and presented as a string.
e.g. sprintf(“%d is the number of %s in a %y”, 12, “months”, “year”)
results in “12 is the number of months in a year”
<html>
<head></head>
<body>
<form method="POST" action="saveAddress.php">
<p>Name <input type="text" name="name" size="40"></p>
<p>Address <input type="text" name="address" size="60"></p>
<p><input type="submit" value="Submit" name="B1">
<input type="reset" value="Reset" name="B2"></p>
</form>
</body>
</html>
Test
saveAddress.php
Guestbook Application
We need:
• A form
• A file (or database table) to hold the data entered
via the form
• Some means of reading the data from the file so
that we can see it
We will look into this case study further when
we move onto databases.
So, what have we got so far?
A means of collecting data from the user
A means of transmitting it to the server
A means of recording it on the server