Example analysis of PHP imitation QQ verification Code

This article introduces a PHP implementation of imitation QQ in the example of verification code, QQ registration or login Verification code, we have seen it, this article gives the code, you can also realize that the verification code oh there is a need for friends, reference under it.


Copy Code code as follows:


<?php


/**


* Imitation QQ Verification Code


*/


//session Save Path


$sessSavePath = dirname (__file__). " /.. /data/sessions/";


if (is_writeable ($sessSavePath) && is_readable ($sessSavePath)) {Session_save_path ($sessSavePath);}


session_start ();


//Get random character


$rndstring = ';


for ($i =0 $i <4; $i + +) $rndstring. = Chr (Mt_rand (65,90));


$img _height=45; First define the long, wide
of the picture

$img _width=10;


//If GD is supported, the drawing


if (function_exists ("Imagecreate"))


{


//firefox Part of the situation will be requested multiple times, refresh the page in 5 seconds will not change session


$ntime = time ();


if (Empty ($_session[' dd_ckstr_last ')) | | | empty ($_session[' dd_ckstr ']) | | ($ntime-$_session[' Dd_ckstr_last '] > 5))


{


$_session[' dd_ckstr ' = Strtolower ($rndstring);


$_session[' dd_ckstr_last ' = $ntime;


}


$rndstring = $_session[' dd_ckstr '];


$rndcodelen = strlen ($rndstring);


//Create picture and set background color


$im = imagecreate (46,20);


imagecolorallocate ($im, 240,243,248);


//Interference line


$lineColor 1 = imagecolorallocate ($im, Mt_rand (174,218), Mt_rand (190,225), Mt_rand (217,237));


for ($j =1 $j <=2; $j = $j +3)


{


imageline ($im, 0, $j +mt_rand (1,15), $j +mt_rand (1,15), $lineColor 1);


}


//Output text


$fontColor = imagecolorallocate ($im, Mt_rand (0,150), Mt_rand (0,150), Mt_rand (0,150));


for ($i =0; $i < $rndcodelen; $i + +)


{


$BC = Mt_rand (0,1);


$rndstring [$i] = Strtoupper ($rndstring [$i]);


imagestring ($im, Mt_rand (3,5), $i * $img _height/4+mt_rand (1,5), Mt_rand (1, $img _WIDTH/2), $rndstring [$i], $ FontColor);


}


header ("Pragma:no-cache" R "N");


header ("Cache-control:no-cache" R "N");


header ("expires:0" R "N");


//output a specific type of picture format, priority for GIF-> jpg->png


if (function_exists ("Imagepng"))


{


header ("Content-type:image/png" R "N");


imagepng ($im);


}


Else


{


header ("Content-type:image/jpeg" R "N");


imagejpeg ($im);


}


Imagedestroy ($im);


exit ();


}


Else


{


//Does not support GD, output only the letter ABCD


$_session[' dd_ckstr ' = "ABCD";


$_session[' dd_ckstr_last '] = ';


Header ("Content-type:image/png" R "N");


header ("Pragma:no-cache" R "N");


header ("Cache-control:no-cache" R "N");


header ("expires:0" R "N");


$fp = fopen ("Data/vdcode.jpg", "R");


Echo fread ($fp, FileSize ("data/vdcode.jpg"));


fclose ($FP);


exit ();


}


?>