Refactors add_hello and adds unit tests.

README.md

@@ -698,6 +698,10 @@ https://lists.boost.org/Archives/boost/2023/01/253944.php.
   [this](https://github.com/boostorg/redis/issues/181#issuecomment-1913346983)
   comment.
 
+* ([Issue 182](https://github.com/boostorg/redis/issues/182)).
+  Sets `"default"` as the default value of `config::username`. This
+  makes it simpler to use the `requirepass` configuration in Redis.
+
 ### Boost 1.84 (First release in Boost)
 
 * Deprecates the `async_receive` overload that takes a response. Users

include/boost/redis/config.hpp

@@ -38,7 +38,7 @@ struct config {
     * [HELLO](https://redis.io/commands/hello/) command.  If left
     * empty `HELLO` will be sent without authentication parameters.
     */
-   std::string username;
+   std::string username = "default";
 
    /** @brief Password passed to the
     * [HELLO](https://redis.io/commands/hello/) command.  If left

include/boost/redis/detail/runner.hpp

@@ -30,6 +30,8 @@
 namespace boost::redis::detail
 {
 
+void push_hello(config const& cfg, request& req);
+
 template <class Runner, class Connection, class Logger>
 struct hello_op {
    Runner* runner_ = nullptr;
@@ -42,9 +44,6 @@ struct hello_op {
    {
       BOOST_ASIO_CORO_REENTER (coro_)
       {
-         runner_->hello_req_.clear();
-         if (runner_->hello_resp_.has_value())
-            runner_->hello_resp_.value().clear();
          runner_->add_hello();
 
          BOOST_ASIO_CORO_YIELD
@@ -232,17 +231,10 @@ class runner {
 
    void add_hello()
    {
-      if (!cfg_.username.empty() && !cfg_.password.empty() && !cfg_.clientname.empty())
-         hello_req_.push("HELLO", "3", "AUTH", cfg_.username, cfg_.password, "SETNAME", cfg_.clientname);
-      else if (cfg_.username.empty() && cfg_.password.empty() && cfg_.clientname.empty())
-         hello_req_.push("HELLO", "3");
-      else if (cfg_.clientname.empty())
-         hello_req_.push("HELLO", "3", "AUTH", cfg_.username, cfg_.password);
-      else
-         hello_req_.push("HELLO", "3", "SETNAME", cfg_.clientname);
-
-      if (cfg_.database_index && cfg_.database_index.value() != 0)
-         hello_req_.push("SELECT", cfg_.database_index.value());
+      hello_req_.clear();
+      if (hello_resp_.has_value())
+         hello_resp_.value().clear();
+      push_hello(cfg_, hello_req_);
    }
 
    bool has_error_in_response() const noexcept

include/boost/redis/impl/runner.ipp

@@ -0,0 +1,27 @@
+/* Copyright (c) 2018-2024 Marcelo Zimbres Silva ([email protected])
+ *
+ * Distributed under the Boost Software License, Version 1.0. (See
+ * accompanying file LICENSE.txt)
+ */
+
+#include <boost/redis/detail/runner.hpp>
+
+namespace boost::redis::detail
+{
+
+void push_hello(config const& cfg, request& req)
+{
+   if (!cfg.username.empty() && !cfg.password.empty() && !cfg.clientname.empty())
+      req.push("HELLO", "3", "AUTH", cfg.username, cfg.password, "SETNAME", cfg.clientname);
+   else if (cfg.password.empty() && cfg.clientname.empty())
+      req.push("HELLO", "3");
+   else if (cfg.clientname.empty())
+      req.push("HELLO", "3", "AUTH", cfg.username, cfg.password);
+   else
+      req.push("HELLO", "3", "SETNAME", cfg.clientname);
+
+   if (cfg.database_index && cfg.database_index.value() != 0)
+      req.push("SELECT", cfg.database_index.value());
+}
+
+} // boost::redis::detail

include/boost/redis/src.hpp

@@ -10,6 +10,7 @@
 #include <boost/redis/impl/ignore.ipp>
 #include <boost/redis/impl/connection.ipp>
 #include <boost/redis/impl/response.ipp>
+#include <boost/redis/impl/runner.ipp>
 #include <boost/redis/resp3/impl/type.ipp>
 #include <boost/redis/resp3/impl/parser.ipp>
 #include <boost/redis/resp3/impl/serialization.ipp>

test/test_low_level_sync_sans_io.cpp

@@ -4,13 +4,17 @@
  * accompanying file LICENSE.txt)
  */
 
+#include <boost/redis/detail/runner.hpp>
 #include <boost/redis/resp3/serialization.hpp>
 #include <boost/redis/adapter/adapt.hpp>
 #define BOOST_TEST_MODULE conn-quit
 #include <boost/test/included/unit_test.hpp>
 #include <string>
 #include <iostream>
 
+using boost::redis::request;
+using boost::redis::config;
+using boost::redis::detail::push_hello;
 using boost::redis::adapter::adapt2;
 using boost::redis::adapter::result;
 using boost::redis::resp3::detail::deserialize;
@@ -31,3 +35,56 @@ BOOST_AUTO_TEST_CASE(low_level_sync_sans_io)
       exit(EXIT_FAILURE);
    }
 }
+
+BOOST_AUTO_TEST_CASE(config_to_hello)
+{
+   config cfg;
+   cfg.clientname = "";
+   request req;
+
+   push_hello(cfg, req);
+
+   std::string_view const expected = "*2\r\n$5\r\nHELLO\r\n$1\r\n3\r\n";
+   BOOST_CHECK_EQUAL(req.payload(), expected);
+}
+
+BOOST_AUTO_TEST_CASE(config_to_hello_with_select)
+{
+   config cfg;
+   cfg.clientname = "";
+   cfg.database_index = 10;
+   request req;
+
+   push_hello(cfg, req);
+
+   std::string_view const expected =
+      "*2\r\n$5\r\nHELLO\r\n$1\r\n3\r\n"
+      "*2\r\n$6\r\nSELECT\r\n$2\r\n10\r\n";
+
+   BOOST_CHECK_EQUAL(req.payload(), expected);
+}
+
+BOOST_AUTO_TEST_CASE(config_to_hello_cmd_clientname)
+{
+   config cfg;
+   request req;
+
+   push_hello(cfg, req);
+
+   std::string_view const expected = "*4\r\n$5\r\nHELLO\r\n$1\r\n3\r\n$7\r\nSETNAME\r\n$11\r\nBoost.Redis\r\n";
+   BOOST_CHECK_EQUAL(req.payload(), expected);
+}
+
+BOOST_AUTO_TEST_CASE(config_to_hello_cmd_auth)
+{
+   config cfg;
+   cfg.clientname = "";
+   cfg.username = "foo";
+   cfg.password = "bar";
+   request req;
+
+   push_hello(cfg, req);
+
+   std::string_view const expected = "*5\r\n$5\r\nHELLO\r\n$1\r\n3\r\n$4\r\nAUTH\r\n$3\r\nfoo\r\n$3\r\nbar\r\n";
+   BOOST_CHECK_EQUAL(req.payload(), expected);
+}