PHP image manipulation class (1/3)_PHP tutorial
php image manipulation class This program can obtain image size, format and other information, and can also perform thumbnail processing and add watermarks to images.
php tutorial image manipulation class
This program can obtain image size, format and other information, and can also perform thumbnail processing on images and add watermarks to images.
1 2 3class image{
public $filename;
private $info;
private $im;
//Construction
public function __construct($filename){
$this->filename = $filename;
$this->info = @getimagesize($filename);
If($this->info[2]>3){echo "Only supports gif, jpeg, png formats.";exit;}
}
//Load
public function imgload(){
switch($this->info[2]){
case 1:
$this->im=@imagecreatefromgif($this->filename);
Break;
Case 2:
$this->im=@imagecreatefromjpeg($this->filename);
Break;
case 3:
$this->im=@imagecreatefrompng($this->filename);
Break;
}
}// Save
public function imagesave($img,$savename,$inf){
switch($inf){
case 1:
Imagegif($img,$savename);;
Break;
Case 2:
Imagejpeg($img,$savename);;
Break;
case 3:
Imagepng($img,$savename);;
Break;
}
//Filter
public function filter($arg=1,$savename=''){
$this->imgload();
if($savename=='')$savename='f_'.$this->filename;
$ok=false;
Switch($arg){
case 1:
Imagefilter($this->im,img_filter_negate);//Invert color
$ok=true;
Break;
case 2:
Imagefilter($this->im,img_filter_grayscale); //Black and white
$ok=true;
Break;
case 3:
Imagefilter($this->im,img_filter_emboss);//Emboss
$ok=true;
Break;
case 4:
Imagefilter($this->im,img_filter_gaussian_blur); //Gaussian blur
$ok=true;
Break;
case 5:
Imagefilter($this->im,img_filter_brightness,50); //Brightness 50
$ok=true;
Break;
case 6:
Imagefilter($this->im,img_filter_contrast,-50); //Contrast-50
$ok=true;
break;
}
if($ok){
$this->imagesave($this->im,$savename,$this->info[2]); //Write file
Imagedestroy($this->im);
Return 1;
}else{
Imagedestroy($this->im);
Return 0;}
}

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The server session failure can be solved through the following steps: 1. Check the server configuration to ensure that the session is set correctly. 2. Verify client cookies, confirm that the browser supports it and send it correctly. 3. Check session storage services, such as Redis, to ensure that they are running normally. 4. Review the application code to ensure the correct session logic. Through these steps, conversation problems can be effectively diagnosed and repaired and user experience can be improved.

session_start()iscrucialinPHPformanagingusersessions.1)Itinitiatesanewsessionifnoneexists,2)resumesanexistingsession,and3)setsasessioncookieforcontinuityacrossrequests,enablingapplicationslikeuserauthenticationandpersonalizedcontent.

Setting the httponly flag is crucial for session cookies because it can effectively prevent XSS attacks and protect user session information. Specifically, 1) the httponly flag prevents JavaScript from accessing cookies, 2) the flag can be set through setcookies and make_response in PHP and Flask, 3) Although it cannot be prevented from all attacks, it should be part of the overall security policy.

PHPsessionssolvetheproblemofmaintainingstateacrossmultipleHTTPrequestsbystoringdataontheserverandassociatingitwithauniquesessionID.1)Theystoredataserver-side,typicallyinfilesordatabases,anduseasessionIDstoredinacookietoretrievedata.2)Sessionsenhances

PHPsessionscanstorestrings,numbers,arrays,andobjects.1.Strings:textdatalikeusernames.2.Numbers:integersorfloatsforcounters.3.Arrays:listslikeshoppingcarts.4.Objects:complexstructuresthatareserialized.

TostartaPHPsession,usesession_start()atthescript'sbeginning.1)Placeitbeforeanyoutputtosetthesessioncookie.2)Usesessionsforuserdatalikeloginstatusorshoppingcarts.3)RegeneratesessionIDstopreventfixationattacks.4)Considerusingadatabaseforsessionstoragei

Session regeneration refers to generating a new session ID and invalidating the old ID when the user performs sensitive operations in case of session fixed attacks. The implementation steps include: 1. Detect sensitive operations, 2. Generate new session ID, 3. Destroy old session ID, 4. Update user-side session information.


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