How to use Springboot +redis+Kaptcha to implement the image verification code function

Background

• Registration-Login-Change password generally requires sending a verification code, but it is easy to be attacked and maliciously called

• What is SMS -Mailbox bomber

• Mobile SMS bomber is a method of sending unlimited SMS registration verification codes for various websites to mobile phones in batches and cycles.

• Loss caused by the company

• One text message costs 5 cents. If it is swiped by a thief, everyone will calculate the email notification for free. Big theft, bandwidth, connections, etc. are all occupied, making it impossible to use normally.

• How to prevent your website from becoming a "broiler" or being brushed

• Add graphic verification code (developer)

• Limit the number of single IP requests (developer)

• Restrict number sending (generally provided by SMS Chamber of Commerce)

• There are always offenses and defenses, but it only increases the cost of the attacker. If the ROI is not enough, it is natural to give up

Kaptcha Framework Introduction

A highly configurable and practical verification code generation tool open source by Google

• Verification code font/size/color

• Range of verification code content (numbers, letters, Chinese characters!)

• Verification code picture size, border, border thickness, border color

• The style of the verification code's interference line verification code (fisheye style, 3D, normal blur)

Add dependency

<!--kaptcha依赖包-->
<dependency>
 <groupId>com.baomidou</groupId>
 <artifactId>kaptcha-spring-bootstarter</artifactId>
 <version>1.0.0</version>
 </dependency>

Configuration Class

/**
 * 图像验证码的配置文件
 * @author : look-word
 * @date : 2022-01-28 17:10
 **/
@Configuration
public class CaptchaConfig {
    /**
     * 验证码配置
     * Kaptcha配置类名
     *
     * @return
     */
    @Bean
    @Qualifier("captchaProducer")
    public DefaultKaptcha kaptcha() {
        DefaultKaptcha kaptcha = new DefaultKaptcha();
        Properties properties = new Properties();
        //验证码个数
        properties.setProperty(Constants.KAPTCHA_TEXTPRODUCER_CHAR_LENGTH, "4");
        //字体间隔
        properties.setProperty(Constants.KAPTCHA_TEXTPRODUCER_CHAR_SPACE,"8");
        //⼲扰线颜⾊

        //⼲扰实现类
        properties.setProperty(Constants.KAPTCHA_NOISE_IMPL, "com.google.code.kaptcha.impl.NoNoise");
        //图⽚样式
        properties.setProperty(Constants.KAPTCHA_OBSCURIFICATOR_IMPL,
                "com.google.code.kaptcha.impl.WaterRipple");
        //⽂字来源
        properties.setProperty(Constants.KAPTCHA_TEXTPRODUCER_CHAR_STRING, "0123456789");
        Config config = new Config(properties);
        kaptcha.setConfig(config);
        return kaptcha;
    }
}

Practical

My configuration class

Tool class for getting access to IP and generating MD5

public class CommonUtil {
    /**
     * 获取ip
     * @param request
     * @return
     */
    public static String
    getIpAddr(HttpServletRequest request) {
        String ipAddress = null;
        try {
            ipAddress = request.getHeader("xforwarded-for");
            if (ipAddress == null ||
                    ipAddress.length() == 0 ||
                    "unknown".equalsIgnoreCase(ipAddress)) {
                ipAddress =
                        request.getHeader("Proxy-Client-IP");
            }
                        request.getHeader("WL-Proxy-Client-IP");
                        request.getRemoteAddr();
                if
                (ipAddress.equals("127.0.0.1")) {
                    // 根据⽹卡取本机配置的IP
                    InetAddress inet = null;
                    try {
                        inet =
                                InetAddress.getLocalHost();
                    } catch (UnknownHostException e) {
                        e.printStackTrace();
                    }
                    ipAddress =
                            inet.getHostAddress();
                }
            // 对于通过多个代理的情况，第⼀个IP为客户端真实IP,多个IP按照','分割
            if (ipAddress != null &&
                    ipAddress.length() > 15) {
                // "***.***.***.***".length()
                // = 15
                if (ipAddress.indexOf(",") > 0)
                {
                            ipAddress.substring(0, ipAddress.indexOf(","));
        } catch (Exception e) {
            ipAddress="";
        }
        return ipAddress;
    }
    public static String MD5(String data) {
            java.security.MessageDigest md =
                    MessageDigest.getInstance("MD5");
            byte[] array =
                    md.digest(data.getBytes("UTF-8"));
            StringBuilder sb = new
                    StringBuilder();
            for (byte item : array) {

                sb.append(Integer.toHexString((item & 0xFF) |
                        0x100).substring(1, 3));
            return sb.toString().toUpperCase();
        } catch (Exception exception) {
        return null;
}

Interface development

@RestController
@RequestMapping("/api/v1/captcha")
public class CaptchaController {

    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    
    private Producer producer;
    @RequestMapping("get_captcha")
    public void getCaptcha(HttpServletRequest request, HttpServletResponse response){
        String captchaText = producer.createText();
        String key = getCaptchaKey(request);
        // 十分钟过期
        stringRedisTemplate.opsForValue().set(key,captchaText,10, TimeUnit.MINUTES);
        BufferedImage image = producer.createImage(captchaText);
        ServletOutputStream outputStream=null;
        try {
            outputStream= response.getOutputStream();
            ImageIO.write(image,"jpg",outputStream);
            outputStream.flush();
            outputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    /**
     * 生成redis验证码模块的key
     * @param request
     * @return
     */
    private String getCaptchaKey(HttpServletRequest request){
        String ipAddr = CommonUtil.getIpAddr(request);
        // 请求头
        String userAgent=request.getHeader("user-Agent");
        String key="user_service:captcha:"+CommonUtil.MD5(ipAddr+userAgent);
        return key;
}

Configuration file

server:
  port: 8080
spring:
  redis:
    host: redis锁在的ip
    password: redis的密码
    port: 端口号
    lettuce:
      pool:
        # 连接池最⼤连接数（使⽤负值表示没有限制）
        max-idle: 10
        # 连接池中的最⼤空闲连接
        max-active: 10
        # 连接池中的最⼩空闲连接
        min-idle: 0
        # 连接池最⼤阻塞等待时间（使⽤负值表示没有限制)
        max-wait: -1ms

Result

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