Support keeping alive with interval (#470)

CMakeLists.txt

@@ -151,6 +151,28 @@ else()
     endif()
 endif()
 
+# Check hiredis features
+message(STATUS "redis-plus-plus check hiredis features")
+if(hiredis_FOUND)
+    set(HIREDIS_FEATURE_TEST_INCLUDE ${hiredis_INCLUDE_DIRS})
+    set(HIREDIS_FEATURE_TEST_LIB ${REDIS_PLUS_PLUS_HIREDIS_LIBS})
+else()
+    set(HIREDIS_FEATURE_TEST_INCLUDE ${HIREDIS_HEADER})
+    set(HIREDIS_FEATURE_TEST_LIB ${HIREDIS_LIB})
+endif()
+set(HIREDIS_FEATURE_TEST_HEADER "${HIREDIS_FEATURE_TEST_INCLUDE}/hiredis/hiredis.h")
+
+include(CheckSymbolExists)
+set(CMAKE_REQUIRED_LIBRARIES_BACK ${CMAKE_REQUIRED_LIBRARIES})
+set(CMAKE_REQUIRED_LIBRARIES ${HIREDIS_FEATURE_TEST_LIB})
+
+CHECK_SYMBOL_EXISTS(redisEnableKeepAliveWithInterval ${HIREDIS_FEATURE_TEST_HEADER} REDIS_PLUS_PLUS_HAS_redisEnableKeepAliveWithInterval)
+
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/hiredis_features.h.in ${CMAKE_CURRENT_SOURCE_DIR}/${REDIS_PLUS_PLUS_SOURCE_DIR}/hiredis_features.h)
+
+# Restore CMAKE_REQUIRED_LIBRARIES
+set(CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES_BACK})
+
 # Build static library
 option(REDIS_PLUS_PLUS_BUILD_STATIC "Build static library" ON)
 message(STATUS "redis-plus-plus build static library: ${REDIS_PLUS_PLUS_BUILD_STATIC}")

hiredis_features.h.in

@@ -0,0 +1 @@
+#cmakedefine REDIS_PLUS_PLUS_HAS_redisEnableKeepAliveWithInterval

src/sw/redis++/connection.cpp

@@ -126,6 +126,16 @@ void Connection::Connector::_set_socket_timeout(redisContext &ctx) const {
 }
 
 void Connection::Connector::_enable_keep_alive(redisContext &ctx) const {
+#ifdef REDIS_PLUS_PLUS_HAS_redisEnableKeepAliveWithInterval
+    if (_opts.keep_alive_s > std::chrono::seconds{0}) {
+        if (redisEnableKeepAliveWithInterval(&ctx, _opts.keep_alive_s.count()) != REDIS_OK) {
+            throw_error(ctx, "Failed to enable keep alive option");
+        }
+
+        return;
+    }
+#endif // end REDIS_PLUS_PLUS_HAS_redisEnableKeepAliveWithInterval
+
     if (!_opts.keep_alive) {
         return;
     }

src/sw/redis++/connection.h

@@ -30,6 +30,7 @@
 #include "sw/redis++/reply.h"
 #include "sw/redis++/utils.h"
 #include "sw/redis++/tls.h"
+#include "sw/redis++/hiredis_features.h"
 
 namespace sw {
 
@@ -67,6 +68,12 @@ struct ConnectionOptions {
 
     bool keep_alive = false;
 
+#ifdef REDIS_PLUS_PLUS_HAS_redisEnableKeepAliveWithInterval
+
+    std::chrono::seconds keep_alive_s = std::chrono::seconds{0};
+
+#endif // end REDIS_PLUS_PLUS_HAS_redisEnableKeepAliveWithInterval
+
     std::chrono::milliseconds connect_timeout{0};
 
     std::chrono::milliseconds socket_timeout{0};