kob/backendCloud/backend/src/main/java/com/kob/backend/service/impl/user/account/acwing/WebServiceImpl.java

package com.kob.backend.service.impl.user.account.acwing;

import com.alibaba.fastjson.JSONObject;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.kob.backend.mapper.UserMapper;
import com.kob.backend.pojo.User;
import com.kob.backend.service.impl.user.account.acwing.utils.HttpClientUtil;
import com.kob.backend.service.user.account.acwing.WebService;
import com.kob.backend.utils.JwtUtil;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.time.Duration;
import java.util.LinkedList;
import java.util.List;
import java.util.Random;

@Service
public class WebServiceImpl implements WebService {
    private static final String appId = "3357";
    private static final String appSecret = "f343ff7eeaa649d2a257bffac0a9323a";
    private static final String redirectUri = "https://kob.bnblogs.cc/user/account/acwing/web/receive_code/";
    private static final String applyAccessTokenUrl = "https://www.acwing.com/third_party/api/oauth2/access_token/";
    private static final String getUserInfoUrl = "https://www.acwing.com/third_party/api/meta/identity/getinfo/";
    private static final Random random = new Random();

    @Autowired
    private UserMapper userMapper;

    @Autowired
    private RedisTemplate<String,String> redisTemplate;

    @Override
    public JSONObject applyCode() {
        JSONObject resp = new JSONObject();
        String encodeUrl="";
        try {
            encodeUrl = URLEncoder.encode(redirectUri,"UTF-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
            resp.put("result","failed");
            return resp;
        }

        StringBuilder state = new StringBuilder();
        for (int i = 0; i < 10; i++) {
            state.append((char)(random.nextInt(10) + '0')); // 十位随机数字字符串
        }
        resp.put("result","success");
        redisTemplate.opsForValue().set(state.toString(),"true"); // 将state值存入redis
        redisTemplate.expire(state.toString(), Duration.ofMinutes(10)); // 设置过期时间为10分钟

        String applyCodeUrl = "https://www.acwing.com/third_party/api/oauth2/web/authorize/?appid=" + appId
                + "&redirect_uri=" + encodeUrl
                + "&scope=userinfo"
                + "&state=" + state;
        resp.put("apply_code_url",applyCodeUrl);
        return resp;
    }

    @Override
    public JSONObject receiveCode(String code, String state) {
        JSONObject resp = new JSONObject();
        resp.put("result","failed");
        if (code == null || state == null) return resp; // 传入的code和state为空
        if (Boolean.FALSE.equals(redisTemplate.hasKey(state))) return resp; // redis中没有该state
        redisTemplate.delete(state); // 删除该state，只使用一次

        // 获取accessToken
        List<NameValuePair> nameValuePairs = new LinkedList<>();
        nameValuePairs.add(new BasicNameValuePair("appid",appId));
        nameValuePairs.add(new BasicNameValuePair("secret",appSecret));
        nameValuePairs.add(new BasicNameValuePair("code",code));

        String getString = HttpClientUtil.get(applyAccessTokenUrl,nameValuePairs); // 请求结果存入一个字符串

        if (getString == null) return resp;

        JSONObject getResp = JSONObject.parseObject(getString);
        String accessToken = getResp.getString("access_token");
        String openId = getResp.getString("openid");

        if (accessToken == null || openId == null) return resp;

        QueryWrapper<User> qw = new QueryWrapper<>();
        qw.eq("openid",openId);
        List<User> users = userMapper.selectList(qw); // 查询满足openid的用户是否存在
        if (!users.isEmpty()) {
            User user = users.get(0);
            String jwt = JwtUtil.createJWT(user.getId().toString());
            resp.put("result","success");
            resp.put("jwt_token",jwt);
            return resp;
        }

        // 如果不存在说明该用户没有登录过，需要根据上面的accessToken和openid向Acwing请求用户信息

        nameValuePairs = new LinkedList<>();
        nameValuePairs.add(new BasicNameValuePair("access_token",accessToken));
        nameValuePairs.add(new BasicNameValuePair("openid",openId));

        getString = HttpClientUtil.get(getUserInfoUrl,nameValuePairs); // 将请求结果存入字符串

        if (getString == null) return resp;
        getResp = JSONObject.parseObject(getString);
        // 获得用户的用户名和头像
        String username = getResp.getString("username");
        String photo = getResp.getString("photo");

        if (username == null || photo == null) return resp;

        // 避免新出现的用户重名
        for (int i = 0; i < 100; i++) { // 随机在后面添加以为数字
            QueryWrapper<User> queryWrapper = new QueryWrapper<>();
            queryWrapper.eq("username",username);
            // 没有重名，直接退出
            if (userMapper.selectList(queryWrapper).isEmpty()) break;
            username += (char)(random.nextInt(10) + '0');
            if (i == 99) return resp; // 小概率事件，太逆天，直接返回
        }

        // 根据获得的信息建立一个用户
        User user = new User(null,username,null,photo,null,openId);
        userMapper.insert(user);

        String jwt = JwtUtil.createJWT(user.getId().toString());

        resp.put("result","success");
        resp.put("jwt_token",jwt);

        return resp;
    }
}