feat(wechat): 重写 code2Session 实现 5 步防御性处理

解决问题： - 微信API返回 text/plain 时 JSONObject.parseObject 抛异常导致用户500 - 网络异常时 RestClientException 未被捕获 - 业务错误码（errcode != 0）未处理实现 5 步防御： 1. 网络层：捕获 ResourceAccessException / RestClientException -> 502 2. HTTP 状态：手动检查 is2xxSuccessful（因 WechatResponseErrorHandler 让 4xx/5xx 不抛）-> 502 3. Content-Type：检查 isCompatibleWith(APPLICATION_JSON) -> 502 4. JSON 解析：try/catch 包裹 parseObject -> 500 5. 业务码：检查 errcode == 0 -> 400 TDD：先写 10 测试场景覆盖所有分支，再实现 - 正常 JSON 成功 - HTTP 4xx / 5xx - Content-Type: text/plain / text/html - JSON 解析失败 - 业务错误码 40029 / 40163 - 网络异常（ResourceAccessException） - 响应缺少 session_key
2026-06-03 23:03:44 +08:00
parent 012fa46d3a
commit 76d4d7465c
2 changed files with 334 additions and 0 deletions
@@ -0,0 +1,110 @@
+package com.emotion.service.impl;
+
+import com.alibaba.fastjson2.JSONObject;
+import com.emotion.config.WechatMiniProgramProperties;
+import com.emotion.dto.wechat.WechatCodeSessionResponse;
+import com.emotion.exception.BusinessException;
+import com.emotion.exception.WechatApiException;
+import com.emotion.service.WechatMiniProgramService;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Service;
+import org.springframework.util.StringUtils;
+import org.springframework.web.client.ResourceAccessException;
+import org.springframework.web.client.RestClientException;
+import org.springframework.web.client.RestTemplate;
+import org.springframework.web.util.UriComponentsBuilder;
+
+import java.util.HashMap;
+import java.util.Map;
+
+@Slf4j
+@Service
+@RequiredArgsConstructor
+public class WechatMiniProgramServiceImpl implements WechatMiniProgramService {
+
+    private final RestTemplate restTemplate;
+    private final WechatMiniProgramProperties properties;
+
+    @Override
+    public WechatCodeSessionResponse code2Session(String code) {
+        validateConfigured();
+
+        String url = UriComponentsBuilder.fromHttpUrl(properties.getBaseUrl() + "/sns/jscode2session")
+                .queryParam("appid", properties.getAppId())
+                .queryParam("secret", properties.getAppSecret())
+                .queryParam("js_code", code)
+                .queryParam("grant_type", "authorization_code")
+                .toUriString();
+
+        ResponseEntity<String> responseEntity;
+        try {
+            responseEntity = restTemplate.getForEntity(url, String.class);
+        } catch (ResourceAccessException e) {
+            // 网络层异常（连接超时、连接拒绝、DNS 失败）
+            log.error("[WeChatAPI] 网络异常，jsCode={}", code, e);
+            throw new WechatApiException(502, "微信API网络异常: " + e.getMessage(), null);
+        } catch (RestClientException e) {
+            // 其他 RestTemplate 异常（如 SSL、URI 解析）
+            log.error("[WeChatAPI] 客户端异常，jsCode={}", code, e);
+            throw new WechatApiException(502, "微信API客户端异常: " + e.getMessage(), null);
+        }
+
+        // Step 2: HTTP 状态码检查（4xx/5xx 不会抛异常，因为 WechatResponseErrorHandler 处理了）
+        if (!responseEntity.getStatusCode().is2xxSuccessful()) {
+            log.error("[WeChatAPI] HTTP 非 2xx 响应，status={}", responseEntity.getStatusCode());
+            throw new WechatApiException(502,
+                "微信API返回非2xx状态: " + responseEntity.getStatusCode(), responseEntity.getBody());
+        }
+
+        // Step 3: Content-Type 检查（防御 WAF 返回 text/plain 拦截页）
+        MediaType contentType = responseEntity.getHeaders().getContentType();
+        if (contentType == null || !MediaType.APPLICATION_JSON.isCompatibleWith(contentType)) {
+            log.error("[WeChatAPI] Content-Type 不是 JSON，contentType={}, body={}",
+                contentType, responseEntity.getBody());
+            throw new WechatApiException(502,
+                "微信API返回非JSON Content-Type: " + contentType, responseEntity.getBody());
+        }
+
+        // Step 4: JSON 解析
+        JSONObject result;
+        try {
+            result = JSONObject.parseObject(responseEntity.getBody());
+        } catch (Exception e) {
+            log.error("[WeChatAPI] JSON 解析失败，body={}", responseEntity.getBody(), e);
+            throw new WechatApiException(500, "微信API响应JSON解析失败: " + e.getMessage(), responseEntity.getBody());
+        }
+
+        // Step 5: 业务错误码检查
+        int errcode = result.getIntValue("errcode");
+        if (errcode != 0) {
+            String errmsg = result.getString("errmsg");
+            log.error("[WeChatAPI] 业务错误，errcode={}, errmsg={}", errcode, errmsg);
+            throw new WechatApiException(400,
+                "微信API业务错误，errcode=" + errcode + ", errmsg=" + errmsg, responseEntity.getBody());
+        }
+
+        // 成功：提取 openid 和 session_key
+        String openid = result.getString("openid");
+        String sessionKey = result.getString("session_key");
+        if (openid == null || sessionKey == null) {
+            log.error("[WeChatAPI] 响应缺少必要字段 (openid 或 session_key)");
+            throw new WechatApiException(502,
+                "微信API响应缺少 openid 或 session_key", responseEntity.getBody());
+        }
+
+        WechatCodeSessionResponse response = new WechatCodeSessionResponse();
+        response.setOpenid(openid);
+        response.setSessionKey(sessionKey);
+        response.setUnionid(result.getString("unionid"));
+        return response;
+    }
+
+    private void validateConfigured() {
+        if (!StringUtils.hasText(properties.getAppId()) || !StringUtils.hasText(properties.getAppSecret())) {
+            throw new BusinessException("微信小程序登录未配置");
+        }
+    }
+}