File Handling in PHP
Hi guys, In this article we are going to understand the handling of files
with a practical approach. File handling functions in PHP are extremely useful
and user-friendly. PHP file handling functions are used in different conditions
in any script development. You need to install XAMPP server. These built in functions give flexibility in
developing complex scripts.
Operations on a file
- Opening the file
- Closing the file
- Reading a file line by line
- Checking the end of file
- Reading a file character by a character
Opening the file in PHP
For opening a file we use the fopen() function. We can open a file or a URL to
read by using the fopen() function of PHP. While opening we can give the mode of file
open ( read, write.. etc ). By using fopen we can read any external URL also.
PHP scripting for the Open file
<html>
<body>
<?php
$file=fopen("yourfile.txt","r");
?>
</body>
</html>
Save it as fileopen.php
To run, open the browser and type in the URL
http://localhost/yourfolder/fileopen.php.
Now here I am going to tell you that,the file can be opened in different mode,
you can use any of the mode as per your requirement.
|
Modes |
Description |
| r |
Read only. Starts at the beginning of the file. |
| r+ |
Read/Write. Starts at the beginning of the file. |
| w |
Write only. Opens and clears the contents of file; or creates a new
file if it doesn't exist. |
| w+ |
Read/Write. Opens and clears the contents of file; or creates a new
file if it doesn't exist. |
| a |
Append. Opens and writes to the end of the file or creates a new
file if it doesn't exist. |
| a+ |
Read/Append. Preserves file content by writing to the end of the
file. |
| x |
Write only. Creates a new file. Returns FALSE and an error if file
already exists. |
| x+ |
Read/Write. Creates a new file. Returns FALSE and an error if file
already exists. |
Closing the file in PHP
From the above description we learn how to open a file now we will learn to
close a open file so for this purpose we use the inbuilt function fclose() .You
should close all files after you have finished with them because it's a good
programming practice.
Discuss the importance of closing a file.
PHP scripting for closing the file
<html>
<body>
<?php
$file
= fopen("test.txt","r");
//some code to be executed
fclose($file);
?>
</body>
</html>
Save it as fileclose.php
To run open browser and type in the URL
http://localhost/yourfolder/fileclose.php.
Reading a File Line by Line in PHP
The fgets() function is used to read a
single line from a file.
PHP scripting for reading a file line by line
<html>
<body>
<?php
$doc
= fopen("yourfilename.txt",
"r")
or
exit("Unable
to open file!");
//result : A line of the file until the end is reached
while(!feof($doc))
{
echo
fgets($doc).
"<br />";
}
fclose($doc);
?>
</body>
</html>
Saved it by rdline.php
To run open browser and type in the URL
http://localhost/yourfolder/rdline.php.
Check
End-of-file in PHP
There are two function which can be
used to find the end of file. The
feof() function checks if the "end-of-file" (EOF) has been reached. The feof()
function is useful for looping through data of unknown length. You cannot read
from files opened in w, a, and x mode. The scripting for understand with
practical approach are as follow :
if (feof($file)) echo "End of file";
Reading a file character by a character in PHP
The fgetc() function is used to read a single character from a file. This is
to reads a file character by character, until the end of file is reached:
<html>
<body>
<?php
$file=fopen("yourfilename.txt","r")
or
exit("Unable
to open file!");
while
(!feof($file))
{
echo
fgetc($file);
}
fclose($file);
?>
</body>
</html>
Saved it as readchar.php
To run, open the browser and type in the URL
http://localhost/yourfolder/readchar.php.