php: Summarize some practical custom functions

Although the function library that comes with PHP is very powerful, in many daily situations, we still have to write our own custom functions to achieve certain functions and requirements. Below is a collection of some more practical custom functions that solve some common needs, such as converting URL strings into hyperlinks, listing directory contents, verifying email addresses, etc.

1. PHP readable random string

This code will create a readable string that is closer to the word in the dictionary, practical and has password verification capabilities.

function readable_random_string($length = 6){
   $conso=array("b","c","d","f","g","h","j","k","l",
   "m","n","p","r","s","t","v","w","x","y","z");
   $vocal=array("a","e","i","o","u");
   $password="";
   srand ((double)microtime()*1000000);
   $max = $length/2;
   for($i=1; $i<=$max; $i++)
   {
   $password.=$conso[rand(0,19)];
   $password.=$vocal[rand(0,4)];
   }
   return $password;
}

2. PHP generates a random string

If you do not need a readable string, use this function instead to create a random string as the user's random password, etc.

function generate_rand($l){
 $c= "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
 srand((double)microtime()*1000000);
 for($i=0; $i < $l; $i++) {
     $rand.= $c[rand()%strlen($c)];
 }
 return $rand;
}

3. PHP encoded email address

Using this code, any email address can be encoded into html Character entities to prevent it from being collected by spam programs.

function encode_email($email='info@domain.com', $linkText='Contact Us', $attrs ='class="emailencoder"' )
 {
     // remplazar aroba y puntos
     $email = str_replace('@', '@', $email);
     $email = str_replace('.', '.', $email);
     $email = str_split($email, 5); 
  
     $linkText = str_replace('@', '@', $linkText);
     $linkText = str_replace('.', '.', $linkText);
     $linkText = str_split($linkText, 5); 
  
     $part1 = &#39;<、a href="ma&#39;;
     $part2 = &#39;ilto:&#39;;
     $part3 = &#39;" &#39;. $attrs .&#39; >&#39;;
     $part4 = &#39;<、/a>&#39;; 
  
     $encoded = &#39;<、script type="text/javascript">&#39;;
     $encoded .= "document.write(&#39;$part1&#39;);";
     $encoded .= "document.write(&#39;$part2&#39;);";
     foreach($email as $e)
     {
             $encoded .= "document.write(&#39;$e&#39;);";
     }
     $encoded .= "document.write(&#39;$part3&#39;);";
     foreach($linkText as $l)
     {
             $encoded .= "document.write(&#39;$l&#39;);";
     }
     $encoded .= "document.write(&#39;$part4&#39;);";
     $encoded .= &#39;<、/script>&#39;; 
  
     return $encoded;
 }

4. PHP verification email address

Email verification is perhaps the most commonly used web pageForm verification. In addition to verifying the email address, this code can also choose to check The MX record in the DNS to which the email domain belongs makes the email verification function more powerful.

function is_valid_email($email, $test_mx = false)
{
   if(eregi("^([_a-z0-9-]+)(\.[_a-z0-9-]+)*@([a-z0-9-]+)(\.[a-z0-9-]+)*(\.[a-z]{2,4})$", $email))
       if($test_mx)
       {
           list($username, $domain) = split("@", $email);
           return getmxrr($domain, $mxrecords);
       }
       else
           return true;
   else
       return false;
}

5. PHP lists directory contents

function list_files($dir)
{
   if(is_dir($dir))
   {
       if($handle = opendir($dir))
       {
           while(($file = readdir($handle)) !== false)
           {
               if($file != "." && $file != ".." && $file != "Thumbs.db"){                     
               echo &#39;<、a target="_blank" href="&#39;.$dir.$file.&#39;">&#39;.$file.&#39;<、/a><、br>&#39;."\n";                 }
           }
           closedir($handle);
       }
   }
}

6. PHP destroys directory

Deletes a directory, including its contents.

function destroyDir($dir, $virtual = false)
{
   $ds = DIRECTORY_SEPARATOR;
   $dir = $virtual ? realpath($dir) : $dir;
   $dir = substr($dir, -1) == $ds ? substr($dir, 0, -1) : $dir;
   if (is_dir($dir) && $handle = opendir($dir))
   {
       while ($file = readdir($handle))
       {
           if ($file == '.' || $file == '..')
           {
               continue;
           }
           elseif (is_dir($dir.$ds.$file))
           {
               destroyDir($dir.$ds.$file);
           }
           else
           {
               unlink($dir.$ds.$file);
           }
       }
       closedir($handle);
       rmdir($dir);
       return true;
   }
   else
   {
       return false;
   }
}

7. PHP parses JSON data

Like most popular web services such as twitter that provide data through open APIs, it always knows how to parse the various transmission formats of API data. , including JSON, XML, etc.

$json_string='{"id":1,"name":"foo","email":"foo@foobar.com","interest":["wordpress","php"]} ';
$obj=json_decode($json_string);
echo $obj->name; //prints foo
echo $obj->interest[1]; //prints php

8. PHP parses XML data

//xml string
 $xml_string="
 <、users>
 <、user id=&#39;398&#39;>
 <、name>Foo<、/name>
 <、email>foo@bar.com<、/name>
 <、/user>
 <、user id=&#39;867&#39;>
 <、name>Foobar<、/name>
 <、email>foobar@foo.com<、/name>
 <、/user>
 <、/users>";
  
 //load the xml string using simplexml
 $xml = simplexml_load_string($xml_string);
  
 //loop through the each node of user
 foreach ($xml->user as $user)
 {
     //access attribute
     echo $user[&#39;id&#39;], &#39; &#39;;
     //subnodes are accessed by -> operator
     echo $user->name, &#39; &#39;;
     echo $user->email, &#39;<、br />&#39;;
 }

9. PHP creates log abbreviation

Create user-friendly log abbreviation.

function create_slug($string){
   $slug=preg_replace('/[^A-Za-z0-9-]+/', '-', $string);
   return $slug;
}

10. PHP gets the client’s real IP address

This function will get the user’s real IP address, even if he uses a proxy server.

function getRealIpAddr()
{
   if (!emptyempty($_SERVER['HTTP_CLIENT_IP']))
   {
       $ip=$_SERVER['HTTP_CLIENT_IP'];
   }
   elseif (!emptyempty($_SERVER['HTTP_X_FORWARDED_FOR']))
   //to check ip is pass from proxy
   {
       $ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
   }
   else
   {
       $ip=$_SERVER['REMOTE_ADDR'];
   }
   return $ip;
}

11. PHP mandatoryFile download

Provides users with mandatory file download function.

function force_download($file)
{
   if ((isset($file))&&(file_exists($file))) {
       header("Content-length: ".filesize($file));
       header('Content-Type: application/octet-stream');
       header('Content-Disposition: attachment; filename="' . $file . '"');
       readfile("$file");
   }
   else {
       echo "No file selected";
   }
}

The above is the detailed content of php: Summarize some practical custom functions. For more information, please follow other related articles on the PHP Chinese website!