PHP: Requires a file called counter1.dat in the same folder as the script

Requires a file called counter1.dat in the same folder as the script
CHMOD the counter file to 755
<?php
//simple counter example v1.0
//open the counter file in read only mode
$counterfile = "counter1.dat";
if(!($fp = fopen($counterfile,"r"))) die ("cannot open counter file");
//read the value stored in the file
$thecount = (int) fread($fp, 20);
//close the file
fclose($fp);
//increment the count
$thecount++;
//display the count
echo "visitor no : $thecount";
//open the file again in write mode and store
// the new count
$fp = fopen($counterfile, "w");
fwrite($fp , $thecount);
//close the file
fclose($fp);
?>

PHP: Atomic time

<?php
$fp = fsockopen("time-a.nist.gov", 37);
if ($fp) {
fputs($fp, "\n");
$timevalue = fread($fp, 49);
fclose($fp);
}

$atomic_time = (abs(hexdec('7fffffff') - hexdec(bin2hex($timevalue)) - hexdec('7fffffff')) - 2208988800);
echo $atomic_time;
?>

This returns the time in the form of a timestamp

PHP: Image to base64 string

<title>Image to Base64 String</title>
<fieldset>
    <legend>Image to Base64 String</legend>
        <center>
        <form name="select_all">
                 <?php 
                /** 
 *   This code will help you to learn how we can convert an image into a base64 string!! 
 */ 
                    echo"<h3><p>Image</p></h3>"; 
                    //$file = File Image yang ingin di encode  
                    //Filetype: JPEG,PNG,GIF 
                    $file = "encode.jpg"; 
                    if($fp = fopen($file,"rb", 0)) 
                    { 
                    $gambar = fread($fp,filesize($file)); 
                    fclose($fp); 

                     
                    $base64 = chunk_split(base64_encode($gambar)); 
                    //Result 
                    $encode = '<img src="data:image/jpg/png/gif;base64,' . $base64 .'" >'; 
                    echo $encode; 
                    }     
                ?> 
                <br><textarea name="text_area" rows="20" cols="70"> <? echo $encode; ?> </textarea>
                <p><input type="button" value="Select All Code" onClick="javascript:this.form.text_area.focus();this.form.text_area.select();"></p>
        </form>
        </center>
    </fieldset>

PHP: Generate CSV file from a PHP array

Here is a simple but efficient function to generate a .csv file from a PHP array. The function accept 3 parameters: the data, the csv delimeter (default is a comma) and the csv enclosure (default is a double quote).

<?php
function generateCsv($data, $delimiter = ',', $enclosure = '"') { 

$handle = fopen('php://temp', 'r+'); 

foreach ($data as $line) { 

fputcsv($handle, $line, $delimiter, $enclosure);

 } 

rewind($handle); 

while (!feof($handle)) { 

$contents .= fread($handle, 8192); 

}

 fclose($handle); 

return $contents; 

}
?>

popen in PHP

popen — Opens process file pointer
Syntax:

resource popen ( string $command , string $mode )
Opens a pipe to a process executed by forking the command given by command.

Parameters:

command
The command

mode
The mode

Return values: Returns a file pointer identical to that returned by fopen(), except that it is unidirectional (may only be used for reading or writing) and must be closed with pclose(). This pointer may be used with fgets(), fgetss(), and fwrite(). When the mode is 'r', the returned file pointer equals to the STDOUT of the command, when the mode is 'w', the returned file pointer equals to the STDIN of the command.

If an error occurs, returns FALSE.



Example #1 popen() example

<?php
$handle = popen("/bin/ls", "r");
?>
If the command to be executed could not be found, a valid resource is returned. This may seem odd, but makes sense; it allows you to access any error message returned by the shell:

Example #2 popen() example

<?php
error_reporting(E_ALL);

/* Add redirection so we can get stderr. */
$handle = popen('/path/to/executable 2>&1', 'r');
echo "'$handle'; " . gettype($handle) . "\n";
$read = fread($handle, 2096);
echo $read;
pclose($handle);
?>


Note:
If you're looking for bi-directional support (two-way), use proc_open().
Note: When safe mode is enabled, you can only execute files within the safe_mode_exec_dir. For practical reasons, it is currently not allowed to have .. components in the path to the executable.
Warning
With safe mode enabled, the command string is escaped with escapeshellcmd(). Thus, echo y | echo x becomes echo y \| echo x.

PHP: File functions In PHP

This chapter will explain following functions related to files:

• Opening a file
• Reading a file
• Writing a file
• Closing a file

Opening and Closing Files

The PHP fopen() function is used to open a file. It requires two arguments stating first the file name and then mode in which to operate.
Files modes can be specified as one of the six options in this table.

Mode	Purpose
r	Opens the file for reading only. Places the file pointer at the beginning of the file.
r+	Opens the file for reading and writing. Places the file pointer at the beginning of the file.
w	Opens the file for writing only. Places the file pointer at the beginning of the file. and truncates the file to zero length. If files does not exist then it attemts to create a file.
w+	Opens the file for reading and writing only. Places the file pointer at the beginning of the file. and truncates the file to zero length. If files does not exist then it attemts to create a file.
a	Opens the file for writing only. Places the file pointer at the end of the file. If files does not exist then it attemts to create a file.
a+	Opens the file for reading and writing only. Places the file pointer at the end of the file. If files does not exist then it attemts to create a file.

If an attempt to open a file fails then fopen returns a value of false otherwise it returns a file pointer which is used for further reading or writing to that file.
After making a changes to the opened file it is important to close it with the fclose() function. The fclose() function requires a file pointer as its argument and then returns true when the closure succeeds or false if it fails.

Reading a file

Once a file is opened using fopen() function it can be read with a function called fread(). This function requires two arguments. These must be the file pointer and the length of the file expressed in bytes.
The files's length can be found using the filesize() function which takes the file name as its argument and returns the size of the file expressed in bytes.
So here are the steps required to read a file with PHP.

• Open a file using fopen() function.
• Get the file's length using filesize() function.
• Read the file's content using fread() function.
• Close the file with fclose() function.

The following example assigns the content of a text file to a variable then displays those contents on the web page.

<html> <head> <title>Reading a file using PHP</title> </head> <body> <?php $filename = "/home/user/guest/tmp.txt"; $file = fopen( $filename, "r" ); if( $file == false ) { echo ( "Error in opening file" ); exit(); } $filesize = filesize( $filename ); $filetext = fread( $file, $filesize ); fclose( $file ); echo ( "File size : $filesize bytes" ); echo ( "<pre>$filetext</pre>" ); ?> </body> </html>

Writing a file

A new file can be written or text can be appended to an existing file using the PHP fwrite() function. This function requires two arguments specifying a file pointer and the string of data that is to be written. Optionally a third integer argument can be included to specify the length of the data to write. If the third argument is included, writing would will stop after the specified length has been reached.
The following example creates a new text file then writes a short text heading insite it. After closing this file its existence is confirmed using file_exist() function which takes file name as an argument

<?php $filename = "/home/user/guest/newfile.txt"; $file = fopen( $filename, "w" ); if( $file == false ) { echo ( "Error in opening new file" ); exit(); } fwrite( $file, "This is a simple test\n" ); fclose( $file ); ?> <html> <head> <title>Writing a file using PHP</title> </head> <body> <?php if( file_exist( $filename ) ) { $filesize = filesize( $filename ); $msg = "File created with name $filename "; $msg .= "containing $filesize bytes"; echo ($msg ); } else { echo ("File $filename does not exit" ); } ?> </body> </html>

We have covered all the function related to file input and out in PHP File System Function chapter.