Uses class specialization instead of function overload. [skip-ci]

Author: mzimbres

example/cpp20_containers.cpp

@@ -1,4 +1,4 @@
-/* Copyright (c) 2018-2022 Marcelo Zimbres Silva ([email protected])
+/* Copyright (c) 2018-2025 Marcelo Zimbres Silva ([email protected])
  *
  * Distributed under the Boost Software License, Version 1.0. (See
  * accompanying file LICENSE.txt)
@@ -24,13 +24,25 @@ using boost::asio::awaitable;
 using boost::asio::detached;
 using boost::asio::consign;
 
+template<class T>
+std::ostream& operator<<(std::ostream& os, std::optional<T> const& opt)
+{
+    if (opt.has_value())
+        std::cout << opt.value();
+    else
+        std::cout << "null";
+
+    return os;
+}
+
 void print(std::map<std::string, std::string> const& cont)
 {
    for (auto const& e: cont)
       std::cout << e.first << ": " << e.second << "\n";
 }
 
-void print(std::vector<int> const& cont)
+template <class T>
+void print(std::vector<T> const& cont)
 {
    for (auto const& e: cont) std::cout << e << " ";
    std::cout << "\n";
@@ -48,6 +60,7 @@ auto store(std::shared_ptr<connection> conn) -> awaitable<void>
    request req;
    req.push_range("RPUSH", "rpush-key", vec);
    req.push_range("HSET", "hset-key", map);
+   req.push("SET", "key", "value");
 
    co_await conn->async_exec(req, ignore);
 }
@@ -67,6 +80,21 @@ auto hgetall(std::shared_ptr<connection> conn) -> awaitable<void>
    print(std::get<0>(resp).value());
 }
 
+auto mget(std::shared_ptr<connection> conn) -> awaitable<void>
+{
+   // A request contains multiple commands.
+   request req;
+   req.push("MGET", "key", "non-existing");
+
+   // Responses as tuple elements.
+   response<std::vector<std::optional<std::string>>> resp;
+
+   // Executes the request and reads the response.
+   co_await conn->async_exec(req, resp);
+
+   print(std::get<0>(resp).value());
+}
+
 // Retrieves in a transaction.
 auto transaction(std::shared_ptr<connection> conn) -> awaitable<void>
 {
@@ -76,11 +104,15 @@ auto transaction(std::shared_ptr<connection> conn) -> awaitable<void>
    req.push("HGETALL", "hset-key"); // Retrieves
    req.push("EXEC");
 
+   // TODO: Retrieve with MGET
    response<
       ignore_t, // multi
       ignore_t, // lrange
       ignore_t, // hgetall
-      response<std::optional<std::vector<int>>, std::optional<std::map<std::string, std::string>>> // exec
+      response<
+         std::optional<std::vector<int>>,
+         std::optional<std::map<std::string, std::string>>
+      > // exec
    > resp;
 
    co_await conn->async_exec(req, resp);
@@ -98,6 +130,7 @@ awaitable<void> co_main(config cfg)
    co_await store(conn);
    co_await transaction(conn);
    co_await hgetall(conn);
+   co_await mget(conn);
    conn->cancel();
 }
 

example/cpp20_json.cpp

@@ -21,12 +21,14 @@
 #include <boost/redis/resp3/serialization.hpp>
 
 namespace asio = boost::asio;
+namespace resp3 = boost::redis::resp3;
 using namespace boost::describe;
 using boost::redis::request;
 using boost::redis::response;
 using boost::redis::ignore_t;
 using boost::redis::config;
 using boost::redis::connection;
+using boost::redis::resp3::node_view;
 
 // Struct that will be stored in Redis using json serialization. 
 struct user {
@@ -40,10 +42,18 @@ BOOST_DESCRIBE_STRUCT(user, (), (name, age, country))
 
 // Boost.Redis customization points (example/json.hpp)
 void boost_redis_to_bulk(std::string& to, user const& u)
-   { boost::redis::resp3::boost_redis_to_bulk(to, boost::json::serialize(boost::json::value_from(u))); }
+{
+   resp3::boost_redis_to_bulk(to, boost::json::serialize(boost::json::value_from(u)));
+}
 
-void boost_redis_from_bulk(user& u, std::string_view sv, boost::system::error_code&)
-   { u = boost::json::value_to<user>(boost::json::parse(sv)); }
+void
+boost_redis_from_bulk(
+   user& u,
+   node_view const& node,
+   boost::system::error_code&)
+{
+   u = boost::json::value_to<user>(boost::json::parse(node.value));
+}
 
 auto co_main(config cfg) -> asio::awaitable<void>
 {

example/cpp20_protobuf.cpp

@@ -19,12 +19,14 @@
 #if defined(BOOST_ASIO_HAS_CO_AWAIT)
 
 namespace asio = boost::asio;
+namespace resp3 = boost::redis::resp3;
 using boost::redis::request;
 using boost::redis::response;
 using boost::redis::operation;
 using boost::redis::ignore_t;
 using boost::redis::config;
 using boost::redis::connection;
+using boost::redis::resp3::node_view;
 
 // The protobuf type described in example/person.proto
 using tutorial::person;
@@ -42,12 +44,16 @@ void boost_redis_to_bulk(std::string& to, person const& u)
    if (!u.SerializeToString(&tmp))
       throw boost::system::system_error(boost::redis::error::invalid_data_type);
 
-   boost::redis::resp3::boost_redis_to_bulk(to, tmp);
+   resp3::boost_redis_to_bulk(to, tmp);
 }
 
-void boost_redis_from_bulk(person& u, std::string_view sv, boost::system::error_code& ec)
+void
+boost_redis_from_bulk(
+   person& u,
+   node_view const& node,
+   boost::system::error_code& ec)
 {
-   std::string const tmp {sv};
+   std::string const tmp {node.value};
    if (!u.ParseFromString(tmp))
       ec = boost::redis::error::invalid_data_type;
 }