PHP/File Directory/fopen

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Acceptable fopen() Modes

 
r        Open the file for reading.
 
r+       Open the file for reading and writing.
 
w        Open the file for writing, overwriting existing files, and creating the file if it does not exist.
 
w+       Open the file for reading and writing, overwriting existing files, and creating the file if it does not exist.
 
a        Open the file for writing, creating the file if it does not exist, and appending to the file if it does.
 
a+       Open the file for reading and writing, creating the file if it does not exist, and appending to the file if it does.
 
b        Open the file in binary reading/writing mode (applicable only on Windows systems; however, recommended in all scripts).



Calling fopen() with a Context Resource

 
<?php
$url = "http://www.wbex.ru/index.htm";
$options = array ("http" => array ("user_agent" => "php24-test-script", "header" => "referer: http://www.example.ru/index.html\r\n" ) );
$context = stream_context_create ( $options );
$res = fopen ( $url, "r", 0, $context ) or die ( "could not open page" );
while ( ! feof ( $res ) ) {
  print fgets ( $res, 1024 );
}
?>



File open with exception checking

 
<?php
try {
    $fh = fopen("data.txt", "r");
    if (! $fh) {
        throw new Exception("Could not open the file!");
    }
}
catch (Exception $e) {
    echo "Error (File: ".$e->getFile().", line ".
          $e->getLine()."): ".$e->getMessage();
}
?>



fopen() function opens a file, returns an integer, as a file handle.

 
Its syntax is: int fopen (string file, string mode [, int use_include_path])
The mode specifies the read/write readiness of the file. 
MODE         MEANING
r            Read only. 
r+           Reading and writing.
w            Write only.
w+           Reading and writing.
a            Write only.
a+           Reading and writing.

If use_include_path is set to 1, file path is compared to the include path contained in the php.ini file. 
<?
    $file = "data.txt";                                             // some file
    $fh = fopen($file, "a+") or die("File ($file) does not exist!");
?>



fopen() requires the file path and the mode in which the file is to be opened.

 
The most common modes are read ("r"), write ("w"), and append ("a"). 
fopen() returns a file resource you will later use to work with the open file. 
To open a file for reading, you would use the following:
$fp = fopen( "test.txt", "r" );

You would use the following to open a file for writing:

$fp = fopen( "test.txt", "w" );

To open a file for appending, you would use this:

$fp = fopen( "test.txt", "a" );



fopen() returns false if the file cannot be opened for any reason.

 
if ( $fp = fopen( "test.txt", "w" ) ) {
  // do something with $fp
}
Or you can use a logical operator to end execution if an essential file can"t be opened:

( $fp = fopen( "test.txt", "w" ) ) or die ("Couldn"t open file, sorry");



Getting and Printing a Web Page with fopen()

 
<html>
<head>
<title>Getting a Web Page with fopen()</title>
</head>
<body>
<div>
<?php
$webpage = "http://www.wbex.ru/index.htm";
$fp = fopen( $webpage, "r" ) or die("couldn"t open $webpage");
while ( ! feof( $fp )) {
  print fgets( $fp, 1024 );
}
?>
</div>
</body>
</html>



Getting and Putting Files with FTP

 
<?php
$file_name = "somefile.ext"; 
$fp = fopen($file_name, "rb");
if ($fp) {
  $data = fread($fp, filesize($file_name));
  fclose($fp);
}
?>



If you are writing a binary file on a Windows system, you should add a "b" flag.

 
$fp = fopen( "binary_file", "wb" );
and read them like this:
$fp = fopen( "binary_file", "rb" );



Load remote file

 
<?php
$file_name = "http://php.net/index.php";
$fp = fopen ( $file_name, "r" );
if ($fp) {
  
  $data = "";
  
  while ( ! feof ( $fp ) ) {
    
    $data .= fread ( $fp, 4096 );
  
  }
  
  fclose ( $fp );
}
echo $data;
?>



Open a connection with the PHP site (http://www.php.net):

 
<?
    $site = "http://www.php.net";      // some server that can communicate via HTTP
    $sh = fopen($site, "r");           // assigns PHP.net index page to a filehandle.
?>



Opening a file

 
<?php
$fh = fopen("file.txt","r") or die("can"t open file.txt: $php_errormsg");
?>



Opening a file on Windows

 
$fh = fopen("c:/settings.txt","rb");



Opening a remote file

 
<?php
$fh = fopen("http://www.example.ru/robots.txt","r") or die($php_errormsg);
?>



Opening Files

 
<?php 
$file = "data.txt"; 
if (file_exists ($file)){ 
    try { 
        if ($readfile = fopen ($file, "r")){ 
            echo "File opened successfully."; 
        } else { 
            throw new exception ("Sorry, the file could not be opened."); 
        } 
    } catch (exception $e) { 
        echo $e->getmessage(); 
    } 
} else { 
    echo "File does not exist."; 
} 
?>



Opening files in the include_path

 
<?php
$fh = fopen("file.inc","r",true) or die("can"t open file.inc: $php_errormsg");
?>



PHP 5 Arguments for Opening a File

 
Argument        Description 
r               Opens a file for reading 
r+              Opens a file for both reading and writing 
w               Opens a file for writing only 
w+              Opens a file for reading and writing 
a               Opens a file for appending (write-only) 
a+              Opens a file for appending (read/write) 
X               Creates a file and opens it for writing only 
x+              Creates a file and opens it for reading and writing 

<?php 
$file = "data.txt"; 
if (file_exists ($file)){ 
    try { 
        if ($readfile = fopen ($file, "r")){ 
            $curvalue = fread ($readfile,100); 
            echo $curvalue; 
        } else { 
            throw new exception ("the file could not be opened."); 
        } 
    } catch (exception $e) { 
        echo $e->getmessage(); 
    } 
} else { 
    echo "File does not exist."; 
} 
?>



Reading a File with fread()

 
<html>
<head>
<title>Reading a File with fread()</title>
</head>
<body>
<div>
<?php
$filename = "data.txt";
$fp = fopen( $filename, "r" ) or die("Couldn"t open $filename");
while ( ! feof( $fp ) ) {
  $chunk = fread( $fp,16 );
  print "$chunk<br/>";
}
?>
</div>
</body>
</html>



Reading from standard input

 
<?php
$fh = fopen("php://stdin","r") or die($php_errormsg);
while($s = fgets($fh)) {
    print "You typed: $s";
}
?>



Safely reading a binary file

 
<?php
$fh = fopen("c:/images/logo.gif","rb");
?>



Using fopen( )

 
<?
    $fp = fsockopen ("data.org", 80);
    if ($fp) {
            fwrite($fp, "GET / HTTP/1.1\r\nHOST: data.org\r\n
                    ACCEPT-ENCODING: gzip\r\n\r\n");
            while (!feof($fp)) {
                    print fread($fp,256);
            }
            fclose ($fp);
    } else {
            print "Fatal error\n";
    }
?>



Using the fopen() Function

 
<?php
     $fr = fopen("myfile.txt", "r");
     $fr = fopen("myfile.dat", "ba+");
     $fr = fopen("code.php", "w+", true);
     $fr = fopen("http://www.php.net/index.php", "r");
     $fr = fopen("ftp://ftp.php.net/index.php", "r");
     $url = "http://www.php.net/this is my invalid URL.php";
     $url = urlencode($url);
     $fr = fopen($url, "r");
?>
Источник — «http://wbex.ru/index.php?title=PHP/File_Directory/fopen&oldid=561»