Using Captcha technology in ThinkPHP6

With the popularity of the Internet, verification code technology has become a routine protection method for websites and applications. CAPTCHAs can prevent malicious robots and crawlers from attacking websites and applications, ensuring the security of user information and privacy. In ThinkPHP6, Captcha technology is built-in, and the verification code function can be easily implemented through simple configuration and call.

1. Basic introduction to Captcha

Captcha is an image verification code technology. Its principle is to display a randomly generated image to the user when the user logs in or submits a form. The requirements The user enters the verification code in the image to proceed. This technology can largely prevent malicious attacks and automated bots from harming a website or application. Common Captcha technologies include numbers, letters or combinations of letters and numbers, voice verification codes, sliding verification codes, etc.

2. Use the Captcha technology built into ThinkPHP6

ThinkPHP6 has a built-in Captcha class, which can easily implement the verification code function. Captcha technology is implemented based on the GD library and session mechanism, and can generate random images of numbers and letters. Before use, you need to ensure that the GD library has been installed and enabled on the server.

1. Configuration file settings

First of all, we need to set the relevant configuration of Captcha in the configuration file config/app.php, including the number of digits of the verification code, the number of verification codes Width and height etc. The configuration is as follows:

'captcha'    => [
        // 验证码位数
        'length'   => 4,
        // 验证码图片宽度
        'width'    => 150,
        // 验证码图片高度
        'height'   => 50,
        // 验证码过期时间（秒）
        'expire'   => 1800,
        // 是否使用中文验证码
        'useZh'    => false,
        // 是否使用算术验证码
        'math'     => false,
        // 是否使用背景图
        'useImgBg' => false,
    ],

In the above configuration, what needs to be noted is:

length: the number of verification code digits, which can be set according to needs;

width and height: verification The width and height of the code image can be set according to needs;

expire: the expiration time of the verification code, in seconds. The verification code will become invalid after the set time;

useZh: whether Use Chinese verification code;

math: Whether to use arithmetic verification code, that is, simple addition and subtraction operations.

useImgBg: Whether to use a background image, you can add a picture as the background of the verification code.

2. Writing of the controller

We need to call the Captcha class in the controller to generate the verification code and display it on the page, and at the same time save the verification code to the session , used to verify whether the entered verification code is correct. The controller code is as follows:

use thinkcaptchaacadeCaptcha;

class Index extends BaseController
{
    public function captcha()
    {
        return Captcha::create();
    }
}

In the above code, we use the static calling method of ThinkPHP6 to generate the verification code directly through the Captcha::create() method. The generated verification code will return a binary image stream, which we can display directly using the tag in the template.

3. Display of the page

Finally, we need to use the tag on the page to display the generated verification code, and submit the verification code when the form is submitted. passed to the server together. The code is as follows:

<form action="submit" method="POST">
    <!-- 显示验证码 -->
    <img src="<?php echo url('/index/captcha'); ?>" onclick="this.src=this.src+'?'+Math.random();" />
    <!-- 输入验证码 -->
    <label for="verifyCode">验证码：</label>
    <input type="text" name="verifyCode" />
    <button type="submit">提交</button>
</form>

In the above code, we use the url() function to generate the Captcha URL address and trigger the regeneration of the verification code through the onclick event. The name of the verification code input box needs to be consistent with the name of the verification code processed by the server, so that the server can correctly obtain the verification code value entered by the user.

3. Summary

Captcha technology has become a conventional protection method for websites and applications. By using the built-in Captcha class in ThinkPHP6, we can easily implement the verification code function. Before use, you need to ensure that the GD library has been installed and opened on the server, and make relevant settings for the Captcha configuration file. Finally, we need to display the verification code on the page and pass the verification code value entered by the user to the server for verification when the form is submitted.

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