This article mainly introduces PHP instances that generate random strings and verification codes. For more information, see
This article mainly introduces PHP instances that generate random strings and verification codes. For more information, see
There are a lot of php random numbers and Verification Code and articles on the Internet. Few of them are actually applicable.
Simply do it yourself.
Let's start the php tutorial in this section. The following code is implemented to distinguish one get_code () and the other create_check_image (). The output image is directly called after session () when the verification code is obtained, get_code () is OK. When using session, session_star () must be placed at the beginning.
The Code is as follows:
The Code is as follows:
Class RandCheckCode
{
/* Function name: get_code ()
* Function: obtain a random string.
* Parameters:
1. (int) $ length = 32 # random character length
2. (int) $ mode = 0 # random character type,
0 is a combination of uppercase and lowercase English letters and numbers, 1 is a number, 2 is a lowercase letter, 3 is a capital letter,
4: uppercase letters, 5: uppercase letters and numbers, 6: lowercase letters and numbers
* Return: The obtained string.
*/
Function get_code ($ length = 32, $ mode = 0) // obtain the Random verification code function
{
Switch ($ mode)
{
Case '1 ':
$ Str = '000000 ';
Break;
Case '2 ':
$ Str = 'abcdefghijklmnopqrstuvwxy ';
Break;
Case '3 ':
$ Str = 'abcdefghijklmnopqrstuvwxy ';
Break;
Case '4 ':
$ Str = 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxy ';
Break;
Case '5 ':
$ Str = 'abcdefghijklmnopqrstuvwxyz1234567890 ';
Break;
Case '6 ':
$ Str = 'abcdefghijklmnopqrstuvwxyz1234567890 ';
Break;
Default:
$ Str = 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz1234567890 ';
Break;
}
$ Checkstr = '';
$ Len = strlen ($ str)-1;
For ($ I = 0; $ I <$ length; $ I ++)
{
// $ Num = rand (0, $ len); // generates a random number between 0 and $ len.
$ Num = mt_rand (0, $ len); // generates a random number between 0 and $ len.
$ Checkstr. = $ str [$ num];
}
Return $ checkstr;
}
/** Function name: create_check_image ()
Function function: generates an image of the verification code.
Parameter: $ checkcode: verification code string
Return Value: returns the image.
*/
Function create_check_image ($ checkcode) // generate
{
$ Im = imagecreate (); // generate an image
$ Black = imagecolorallocate ($ im, 0, 0); // background color
$ White = imagecolorallocate ($ im, 255,255,255); // foreground color
$ Gray = imagecolorallocate ($ im, 200,200,200 );
Imagefill ($ im, 30, 30, $ gray); // The coordinates of the $ im image are 30, 30 (the upper left corner of the image is 0, 0) fill the area with the $ gray color (that is, the adjacent points will be filled with the same color as the 30, 30 points)
Imagestring ($ im, 5, 8, 3, $ checkcode, $ white ); // use the $ white color to draw the string $ checkcode to the 8, 3 coordinates of the image represented by $ im (this is the coordinate of the upper left corner of the string, the upper left corner of the entire image is 0, 0), and 5 is the font size, the font can only be 1, 2, 3, 4, or 5. the built-in font is used.
For ($ I = 0; I I <120; $ I ++)
{
$ Randcolor = imagecolorallocate ($ im, rand (0,255), rand (0,255), rand (0,255 ));
Imagesetpixel ($ im, rand () % 70, rand () % 30, $ randcolor); // use $ randcolor on $ im images at (rand () % 70, rand () % 30) Coordinate (the upper left corner of the image is 0, 0 ).
}
Header ("Content-type: image/png ");
Imagepng ($ im); // output the image to a browser or file in PNG format
Imagedestroy ($ im); // destroy the image $ im
}
}
/*
$ Randcode = new RandCheckCode ();
$ Checkstring = $ randcode-> get_code (5, 7 );
$ Image = $ randcode-> create_check_image ($ checkstring );
Echo $ image;
*/
?>