From e2e5d6d57f26b79bab83e87d1d3596d077925603 Mon Sep 17 00:00:00 2001
From: Nitromelon <hwc14@qq.com>
Date: Thu, 31 Aug 2023 19:19:58 +0800
Subject: [PATCH] Allow omitting template paremeter in execCommandSync. (#1764)

---
 .../redis/inc/drogon/nosql/RedisClient.h      | 30 ++++++++++++++-----
 nosql_lib/redis/tests/redis_test.cc           |  9 ++++--
 2 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/nosql_lib/redis/inc/drogon/nosql/RedisClient.h b/nosql_lib/redis/inc/drogon/nosql/RedisClient.h
index 97615c0c..498666c5 100644
--- a/nosql_lib/redis/inc/drogon/nosql/RedisClient.h
+++ b/nosql_lib/redis/inc/drogon/nosql/RedisClient.h
@@ -164,26 +164,40 @@ class DROGON_EXPORT RedisClient
                       std::string_view command,
                       Args &&...args)
     {
-        std::shared_ptr<std::promise<T>> pro(new std::promise<T>);
-        std::future<T> f = pro->get_future();
+        return execCommandSync<std::decay_t<decltype(processFunc)>>(
+            std::move(processFunc), command, std::forward<Args>(args)...);
+    }
+
+    /**
+     * @brief Execute a redis command synchronously
+     * Return type can be deduced automatically in this version.
+     */
+    template <typename F, typename... Args>
+    std::invoke_result_t<F, const RedisResult &> execCommandSync(
+        F &&processFunc,
+        std::string_view command,
+        Args &&...args)
+    {
+        using Ret = std::invoke_result_t<F, const RedisResult &>;
+        std::promise<Ret> prom;
         execCommandAsync(
-            [process = std::move(processFunc), pro](const RedisResult &result) {
+            [&processFunc, &prom](const RedisResult &result) {
                 try
                 {
-                    pro->set_value(process(result));
+                    prom.set_value(processFunc(result));
                 }
                 catch (...)
                 {
-                    pro->set_exception(std::current_exception());
+                    prom.set_exception(std::current_exception());
                 }
             },
-            [pro](const RedisException &err) {
-                pro->set_exception(std::make_exception_ptr(err));
+            [&prom](const RedisException &err) {
+                prom.set_exception(std::make_exception_ptr(err));
             },
             command,
             std::forward<Args>(args)...);
 
-        return f.get();
+        return prom.get_future().get();
     }
 
     /**
diff --git a/nosql_lib/redis/tests/redis_test.cc b/nosql_lib/redis/tests/redis_test.cc
index 552b2065..6a1c9825 100644
--- a/nosql_lib/redis/tests/redis_test.cc
+++ b/nosql_lib/redis/tests/redis_test.cc
@@ -168,11 +168,14 @@ DROGON_TEST(RedisTest)
         SUCCESS();
     }
 
+    // 12. Test omit template parameter
     try
     {
-        redisClient->execCommandSync<int>([](const RedisResult &) { return 1; },
-                                          "del %s",
-                                          "sync_key");
+        auto i = redisClient->execCommandSync(
+            [](const RedisResult &r) { return r.asInteger(); },
+            "del %s",
+            "sync_key");
+        MANDATE(i == 1);
     }
     catch (const RedisException &err)
     {