PHP Tutorial - PHP fopen() Function

Definition

The fopen() function opens a file or URL.

fopen() is lifted straight from C,

Syntax

PHP fopen() Function has the following syntax.

fopen(filename,mode,include_path,context)

Parameter

Parameter	Is required	Description
filename	Required.	File or URL to open
mode	Required.	Type of access you require to the file/stream.
include_path	Optional.	Set to '1' to search for the file in the include_path in php.ini
context	Optional.	Context of the file handle.

Possible values for mode:

Mode	Meaning	Note
"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"	Write only.	Opens and writes to the end of the file or creates a new file if it doesn't exist
"a+"	Read/Write.	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

Return

Returns a file pointer resource on success, or FALSE on error.

We can hide the error output by adding an '@' in front of the function name.

Example 1

Take a look at the following usages:

$file1 = fopen("file.txt", "r") OR die ("Can't open file!\n");
$file2= fopen("$logFileName", "w") OR die ("Log file not writeable!\n");

The fopen() function returns a file handle resource. You should store the return value of fopen() in a variable for later use:


<?PHP
      $filename = "c:/abc/test.txt";
      $handle = fopen($filename, "a");
      if (!$handle) {
             print "Failed to open $filename for appending.\n";
      }
?>

Example - Open Remote Files

The fopen() can specify remote files. PHP automatically opens a HTTP/FTP connection for you, returning the file handle.

This example displays the google web site through your browser:


<?PHP
$google = fopen("http://www.google.org", "r");
$site = fread($google, 200000);
fclose($google);
print $site;
?>

The r mode is specified because web servers do not allow writing through HTTP,

$file = fopen("http://www.example.com/","r");
$file = fopen("ftp://user:password@example.com/test.txt","w");

The code above generates the following result.

Example 2

The following code shows how to open a file or URL.


/*from w ww  . j av a2s  .  co  m*/


<?php
    $file = fopen("test.txt","r");
    $file = fopen("test.txt","r");
    $file = fopen("test.txt","wb");
    $file = fopen("http://www.example.com/","r");
    $file = fopen("ftp://user:password@example.com/test.txt","w");

/*
      "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" (Write only. Opens and writes to the end of the file or creates a new file if it doesn't exist)
      "a+" (Read/Write. 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)

*/
?>

Example 3

The following code shows how to open existing file "test.txt", and write some new data into it.



<?php
   $myfile = fopen("test.txt", "w") or die("Unable to open file!");
   $txt = "data\n";
   fwrite($myfile, $txt);
   $txt = "data\n";
   fwrite($myfile, $txt);
   fclose($myfile);
?>