IT420: Database Management and Organization – Using Files PHP
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IT420: Database Management
and Organization
PHP – Using Files
1 March 2006
Adina Crainiceanu
www.cs.usna.edu/~adina
Storing and Retrieving Data
Write data to file
Open file
Write data to file
Close the file
Read data from file
Open file
Read from file
Close file
Open File
$fp = fopen(filename,mode);
Test for errors and handle them!
name_age.php
Suppress the error!
<html>
<body>
Welcome <?php echo $_POST[‘name’]; ?>.<br />
You are <?php echo $_POST[‘age’]; ?> years old! <br/>
<?php @ $fp = fopen(“names.txt”,’w’);
if (!$fp){
echo ‘Your name could not be added. ’
. ‘Try again later</body></html>’;
exit;
}
else{
echo ‘Your name will be added to a file.’;
}
?>
</body>
</html>
Exit the php script.
Open File
$fp = fopen(“orders.txt”,’w’);
File Modes
Description
r
Read only
r+
Read/Write.
w
Write only. Overwrites. Creates.
w+
Read/Write. Overwrites. Creates.
a
Append. Creates
a+
Read/Append. Creates
x
Create and open for write only. If exists, fail.
x+
Create and open for read/write. If exists, fail.
Write into File
int fwrite(filePointer, string [, stringLength])
int fputs(filePointer, string [, stringLength])
int file_put_contents(fileName, stringOrArray)
Starting in PHP 5 only!
Example:
$outputstring = $name. “\t”. $age. “\n”;
fwrite($fp, $outputstring);
Close File
int fclose(filePointer)
Example: fclose($fd);
Class Exercise
Create PHP script to:
Open/create a file, without overwriting it
Write the numbers 1 to 20 to file, separated by
space
Close the file
Retrieve Data from File
Open file for reading
$fp = fopen(“names.txt”, ‘r’);
Test and handle errors!
Start reading
Stop when end of file reached
feof(filePointer) == true
Read Line from File
string = fgets(filePointer, maxLength)
Read one line, up to maxLength-1 bytes
string = fgetss(filePointer, maxLength
[, allowableTags])
Like fgets, but strip out any PHP or HTML tags found
in the string
array = fgetcsv(filePointer, maxLength [, string
delimiter])
Like fgets, but breaks the string into components
Read Data Example
<?php
@ $fp = fopen(“names.txt”, ‘r’);
if (!$fp){
echo ‘No names in file.’;
}
else{
while( !feof($fd) ){
$name_age = fgets($fp, 500);
echo $name_age.’<br>’;
}
fclose($fp);
}
?>
Read Whole File
int readfile(fileName)
Open file
Read content, echo it to the browser
Close file
fpassthru(filePointer)
Read content, echo it to the browser
Close file
array file(fileName)
string file_get_contents(fileName)
Other Reads
char fgetc(filePointer)
string fread(filePointer, nbBytes)
Useful File Functions
boolean file_exists(fileName)
int filesize(fileName)
unlink(fileName)
//deletes the file
Locking
What if multiple users try to read/write the
file in the same time?
flock(filePointer, lockType)
LOCK_SH
LOCK_EX
LOCK_UN
// read
// write
//release lock
PHP Configuration
Display the errors
Open Sokkit Control Panel
Click on “PHP Config”
Search for “display_errors = Off”
Change to “On” and remove ; at the beginning of line
Search for “error_reporting = E_ALL”
Remove the ; at the beginning of line
Save and return to Main Menu
Restart Web Server
Copy some bad .php file to D:\sokkit\site
Run the file (http://localhost/fileName.php)
Lab Exercise
Save order data from VP-5 Fund Raiser
application into a file. Display appropriate
message in order confirmation screen.
Display all orders from VP-5 Fund Raiser
application.
Display all orders from VP-5 Fund Raiser
application with shipping address in Maryland.
Use strstr(longString,shortString) to check if ‘MD’
is in shipping address.
