From a571bf354692a4f28c678ccb59fcc6b27164bcee Mon Sep 17 00:00:00 2001
From: yangyl12345 <yangyl971227@gmail.com>
Date: Tue, 26 Nov 2024 12:13:49 +0800
Subject: [PATCH] Update default_access_token.go (#805)
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* Update default_access_token.go

微信获取稳定版token，只有不等于空字符串的情况下才会返回access_token信息，未空的情况，继续调去微信服务

* 微信稳定性获取 access_token 接口，添加防止并发性获取 access_token 和多次微信服务获取代码

---------

Co-authored-by: w_yangyili <w_yangyili@xiwang.com>
---
 credential/default_access_token.go | 33 ++++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/credential/default_access_token.go b/credential/default_access_token.go
index 00ad481..ec88a89 100644
--- a/credential/default_access_token.go
+++ b/credential/default_access_token.go
@@ -101,10 +101,11 @@ func (ak *DefaultAccessToken) GetAccessTokenContext(ctx context.Context) (access
 // 不强制更新access_token,可用于不同环境不同服务而不需要分布式锁以及公用缓存，避免access_token争抢
 // https://developers.weixin.qq.com/miniprogram/dev/OpenApiDoc/mp-access-token/getStableAccessToken.html
 type StableAccessToken struct {
-	appID          string
-	appSecret      string
-	cacheKeyPrefix string
-	cache          cache.Cache
+	appID           string
+	appSecret       string
+	cacheKeyPrefix  string
+	cache           cache.Cache
+	accessTokenLock *sync.Mutex
 }
 
 // NewStableAccessToken new StableAccessToken
@@ -113,10 +114,11 @@ func NewStableAccessToken(appID, appSecret, cacheKeyPrefix string, cache cache.C
 		panic("cache is need")
 	}
 	return &StableAccessToken{
-		appID:          appID,
-		appSecret:      appSecret,
-		cache:          cache,
-		cacheKeyPrefix: cacheKeyPrefix,
+		appID:           appID,
+		appSecret:       appSecret,
+		cache:           cache,
+		cacheKeyPrefix:  cacheKeyPrefix,
+		accessTokenLock: new(sync.Mutex),
 	}
 }
 
@@ -130,7 +132,20 @@ func (ak *StableAccessToken) GetAccessTokenContext(ctx context.Context) (accessT
 	// 先从cache中取
 	accessTokenCacheKey := fmt.Sprintf("%s_stable_access_token_%s", ak.cacheKeyPrefix, ak.appID)
 	if val := ak.cache.Get(accessTokenCacheKey); val != nil {
-		return val.(string), nil
+		if accessToken = val.(string); accessToken != "" {
+			return
+		}
+	}
+
+	// 加上lock，是为了防止在并发获取token时，cache刚好失效，导致从微信服务器上获取到不同token
+	ak.accessTokenLock.Lock()
+	defer ak.accessTokenLock.Unlock()
+
+	// 双检，防止重复从微信服务器获取
+	if val := ak.cache.Get(accessTokenCacheKey); val != nil {
+		if accessToken = val.(string); accessToken != "" {
+			return
+		}
 	}
 
 	// cache失效，从微信服务器获取