kxs-java/kxs-gateway/src/main/java/com/kxs/gateway/api/handler/ImageCodeHandler.java

package com.kxs.gateway.api.handler;

import cn.hutool.captcha.CaptchaUtil;
import cn.hutool.captcha.LineCaptcha;
import cn.hutool.captcha.generator.RandomGenerator;
import com.kxs.common.core.constant.CacheConstants;
import com.kxs.common.core.constant.SecurityConstants;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.core.io.ByteArrayResource;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.util.FastByteArrayOutputStream;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.server.HandlerFunction;
import org.springframework.web.reactive.function.server.ServerRequest;
import org.springframework.web.reactive.function.server.ServerResponse;
import reactor.core.publisher.Mono;

import java.util.Optional;
import java.util.concurrent.TimeUnit;

/**
 * 验证码生成逻辑处理类
 *
 * @author 没秃顶的码农
 * @date 2023/11/03
 */
@Slf4j
@RequiredArgsConstructor
public class ImageCodeHandler implements HandlerFunction<ServerResponse> {

	private static final Integer DEFAULT_IMAGE_WIDTH = 100;

	private static final Integer DEFAULT_IMAGE_HEIGHT = 40;

	private final RedisTemplate<String, Object> redisTemplate;

	@Override
	public Mono<ServerResponse> handle(ServerRequest serverRequest) {

		// 保存验证码信息
		Optional<String> randomStr = serverRequest.queryParam("randomStr");

		// 生成验证码
		RandomGenerator randomGenerator = new RandomGenerator("0123456789", 4);
		LineCaptcha lineCaptcha = CaptchaUtil.createLineCaptcha(DEFAULT_IMAGE_WIDTH, DEFAULT_IMAGE_HEIGHT);
		lineCaptcha.setGenerator(randomGenerator);

		redisTemplate.setKeySerializer(new StringRedisSerializer());
		randomStr.ifPresent(s -> redisTemplate.opsForValue()
			.set(CacheConstants.DEFAULT_CODE_KEY + s, lineCaptcha.getCode(), SecurityConstants.CODE_TIME,
					TimeUnit.SECONDS));

		// 转换流信息写出
		FastByteArrayOutputStream os = new FastByteArrayOutputStream();
		lineCaptcha.write(os);
		return ServerResponse.status(HttpStatus.OK)
			.contentType(MediaType.IMAGE_JPEG)
			.body(BodyInserters.fromResource(new ByteArrayResource(os.toByteArray())));

	}

}