How thinkphp implements front-end and back-end separation verification code

1. The role of verification code

In the Internet era, we often use verification codes to enhance security. Implementing the verification code function can help us:

1. Prevent robot attacks: The verification code can detect whether it is a human operation to reduce attacks by malicious robots and hackers.

2. Improve security: Verification codes can strengthen permission control, ensure the authenticity of user identities, and protect servers and websites from unnecessary attacks.

3. Improve user experience: Verification codes can effectively prevent users from losing interest due to continuous illegible characters.

2. Front-end verification code implementation

In the process of front-end implementation of verification code, we need the following main steps:

1. Determine the type of verification code: Verification codes are usually divided into character verification codes and graphic verification codes. Design with user experience and security in mind.

2. Generate verification code on front-end page: Use Canvas or other technology to generate verification code on front-end page. It is possible to use the HTML5 Canvas element to customize the font, size and color of the verification code.

3. Generally, we need to verify whether the user input matches the verification code generated by the server. Through JavaScript and Ajax technology, we are able to obtain user input and send it to the server side.

4. Verification verification code: Verify user input on the server side. If an API interface is provided, the interface will return information such as verification success or failure to the client.

By using these technologies, users can obtain verification codes at the front desk to avoid automated malicious access or attacks.

3. Back-end verification code implementation

When implementing verification code in thinkphp, we usually need to pay attention to the following aspects:

1. Create a verification code controller

To control the generation and verification of verification codes, you can place the verification code controller in the background directory. In the controller, the following methods are usually included:

• generateCode: Generate a verification code and store the verification code in the Session.

• verifyCode: Verify whether the verification code entered by the user is correct.

• getCode: Returns the verification code stored in Session.

2. Generate verification code

When generating the verification code, we can use the GD library to generate the image, and then pass The way to output the image and save the image, send the result of the verification code to the client. The following is a sample code:

public function generateCode($width=80,$height=22,$verifyName=''){
    //生成一个4位的随机字符串
    $code = '';
    $chars = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
    for($i=0;$i<4;$i++){
        $code .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
    }
    //将验证码存储到session中
    if($verifyName){
        session($verifyName, $code);
    }else{
        session(&#39;verify_code&#39;, $code);
    }

    //生成验证码图像
    $img = imagecreate($width,$height);
    //背景色
    imagecolorallocate($img, 102,102,102);
    //字体颜色
    $color = imagecolorallocate($img, 255, 255, 255);
    //生成干扰线
    for($i=0;$i<5;$i++){
        imageline($img,mt_rand(0,$width/2),mt_rand(0,$height/2),mt_rand($width/2,$width),mt_rand($height/2,$height),$color);
    }
    //将验证码绘制到图像上
    imagefttext($img, 18, 0, 10, $height-5, $color, &#39;./arial.ttf&#39;, $code);
    //输出图像
    header(&#39;Pragma:no-cache&#39;);
    header(&#39;Cache-Control:no-cache&#39;);
    header("content-type:image/png");
    imagepng($img);
    imagedestroy($img);
}

3. Verification verification code

We generally get the verification code entered by the user, and then find the corresponding verification code in the session Verification code value to verify. When the verification code value stored in the session is the same as the value entered by the user, the verification code verification is successful.

// 验证码验证
if(empty($verify)) {
    $this->error('验证码不能为空！');
}
if($verify != session('verify_code')){
    $this->error("验证码错误！");
}

4. Advantages of front-end and back-end separation verification code implementation

The front-end and front-end separation method allows back-end developers to focus on data processing and logical business, and the front-end Developers can focus on the development of user experience and interaction methods. Utilizing front-end and back-end separation, the security of websites and web applications can be improved, and verification codes can be applied to effectively block malicious automated access and attacks.

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