Do async-resove in ctor

examples/asio-cl.cc

@@ -62,10 +62,7 @@ int main(int argc, char *argv[]) {
     boost::asio::ssl::context tls_ctx(boost::asio::ssl::context::sslv23);
     configure_tls_context(tls_ctx);
 
-    tcp::resolver resolver(io_service);
-    auto endpoint_it = resolver.resolve({"localhost", "3000"});
-
-    session sess(io_service, tls_ctx, endpoint_it);
+    session sess(io_service, tls_ctx, "localhost", "3000");
     sess.on_connect([&sess]() {
       std::cerr << "connected" << std::endl;
       boost::system::error_code ec;

src/asio_client_session.cc

@@ -37,14 +37,15 @@ namespace client {
 
 using boost::asio::ip::tcp;
 
-session::session(boost::asio::io_service &io_service,
-                 tcp::resolver::iterator endpoint_it)
-    : impl_(make_unique<session_tcp_impl>(io_service, endpoint_it)) {}
+session::session(boost::asio::io_service &io_service, const std::string &host,
+                 const std::string &service)
+    : impl_(make_unique<session_tcp_impl>(io_service, host, service)) {}
 
 session::session(boost::asio::io_service &io_service,
-                 boost::asio::ssl::context &tls_ctx,
-                 tcp::resolver::iterator endpoint_it)
-    : impl_(make_unique<session_tls_impl>(io_service, tls_ctx, endpoint_it)) {}
+                 boost::asio::ssl::context &tls_ctx, const std::string &host,
+                 const std::string &service)
+    : impl_(make_unique<session_tls_impl>(io_service, tls_ctx, host, service)) {
+}
 
 session::~session() {}
 
@@ -54,6 +55,8 @@ void session::on_error(error_cb cb) { impl_->on_error(std::move(cb)); }
 
 void session::shutdown() { impl_->shutdown(); }
 
+boost::asio::io_service &session::io_service() { return impl_->io_service(); }
+
 request *session::submit(boost::system::error_code &ec,
                          const std::string &method, const std::string &uri,
                          header_map h) {

src/asio_client_session_impl.cc

@@ -38,8 +38,9 @@ namespace nghttp2 {
 namespace asio_http2 {
 namespace client {
 
-session_impl::session_impl()
-    : wblen_(0), session_(nullptr), data_pending_(nullptr), data_pendinglen_(0),
+session_impl::session_impl(boost::asio::io_service &io_service)
+    : wblen_(0), io_service_(io_service), resolver_(io_service),
+      session_(nullptr), data_pending_(nullptr), data_pendinglen_(0),
       writing_(false), inside_callback_(false) {}
 
 session_impl::~session_impl() {
@@ -53,6 +54,20 @@ session_impl::~session_impl() {
   nghttp2_session_del(session_);
 }
 
+void session_impl::start_resolve(const std::string &host,
+                                 const std::string &service) {
+  resolver_.async_resolve({host, service},
+                          [this](const boost::system::error_code &ec,
+                                 tcp::resolver::iterator endpoint_it) {
+    if (ec) {
+      not_connected(ec);
+      return;
+    }
+
+    start_connect(endpoint_it);
+  });
+}
+
 void session_impl::connected() {
   if (!setup_session()) {
     return;
@@ -411,6 +426,8 @@ void session_impl::shutdown() {
   signal_write();
 }
 
+boost::asio::io_service &session_impl::io_service() { return io_service_; }
+
 void session_impl::signal_write() {
   if (!inside_callback_) {
     do_write();

src/asio_client_session_impl.h

@@ -45,9 +45,11 @@ using boost::asio::ip::tcp;
 
 class session_impl {
 public:
-  session_impl();
+  session_impl(boost::asio::io_service &io_service);
   virtual ~session_impl();
 
+  void start_resolve(const std::string &host, const std::string &service);
+
   void connected();
   void not_connected(const boost::system::error_code &ec);
 
@@ -67,6 +69,7 @@ public:
   request *submit(boost::system::error_code &ec, const std::string &method,
                   const std::string &uri, read_cb cb, header_map h);
 
+  virtual void start_connect(tcp::resolver::iterator endpoint_it) = 0;
   virtual tcp::socket &socket() = 0;
   virtual void read_socket(std::function<
       void(const boost::system::error_code &ec, std::size_t n)> h) = 0;
@@ -76,6 +79,8 @@ public:
 
   void shutdown();
 
+  boost::asio::io_service &io_service();
+
   void signal_write();
 
   void enter_callback();
@@ -93,6 +98,9 @@ private:
   bool should_stop() const;
   bool setup_session();
 
+  boost::asio::io_service &io_service_;
+  tcp::resolver resolver_;
+
   std::map<int32_t, std::unique_ptr<stream>> streams_;
 
   void_cb connect_cb_;

src/asio_client_session_tcp_impl.cc

@@ -29,22 +29,27 @@ namespace asio_http2 {
 namespace client {
 
 session_tcp_impl::session_tcp_impl(boost::asio::io_service &io_service,
-                                   tcp::resolver::iterator endpoint_it)
-    : socket_(io_service) {
-
-  boost::asio::async_connect(socket_, endpoint_it,
-                             [this](boost::system::error_code ec,
-                                    tcp::resolver::iterator endpoint_it) {
-    if (!ec) {
-      connected();
-      return;
-    }
-    not_connected(ec);
-  });
+                                   const std::string &host,
+                                   const std::string &service)
+    : session_impl(io_service), socket_(io_service) {
+  start_resolve(host, service);
 }
 
 session_tcp_impl::~session_tcp_impl() {}
 
+void session_tcp_impl::start_connect(tcp::resolver::iterator endpoint_it) {
+  boost::asio::async_connect(socket_, endpoint_it,
+                             [this](const boost::system::error_code &ec,
+                                    tcp::resolver::iterator endpoint_it) {
+    if (ec) {
+      not_connected(ec);
+      return;
+    }
+
+    connected();
+  });
+}
+
 tcp::socket &session_tcp_impl::socket() { return socket_; }
 
 void session_tcp_impl::read_socket(

src/asio_client_session_tcp_impl.h

@@ -39,10 +39,11 @@ using boost::asio::ip::tcp;
 
 class session_tcp_impl : public session_impl {
 public:
-  session_tcp_impl(boost::asio::io_service &io_service,
-                   tcp::resolver::iterator endpoint_it);
+  session_tcp_impl(boost::asio::io_service &io_service, const std::string &host,
+                   const std::string &service);
   virtual ~session_tcp_impl();
 
+  virtual void start_connect(tcp::resolver::iterator endpoint_it);
   virtual tcp::socket &socket();
   virtual void read_socket(std::function<
       void(const boost::system::error_code &ec, std::size_t n)> h);

src/asio_client_session_tls_impl.cc

@@ -30,11 +30,17 @@ namespace client {
 
 session_tls_impl::session_tls_impl(boost::asio::io_service &io_service,
                                    boost::asio::ssl::context &tls_ctx,
-                                   tcp::resolver::iterator endpoint_it)
-    : socket_(io_service, tls_ctx) {
+                                   const std::string &host,
+                                   const std::string &service)
+    : session_impl(io_service), socket_(io_service, tls_ctx) {
+  start_resolve(host, service);
+}
 
+session_tls_impl::~session_tls_impl() {}
+
+void session_tls_impl::start_connect(tcp::resolver::iterator endpoint_it) {
   boost::asio::async_connect(socket(), endpoint_it,
-                             [this](boost::system::error_code ec,
+                             [this](const boost::system::error_code &ec,
                                     tcp::resolver::iterator endpoint_it) {
     if (ec) {
       not_connected(ec);
@@ -52,8 +58,6 @@ session_tls_impl::session_tls_impl(boost::asio::io_service &io_service,
   });
 }
 
-session_tls_impl::~session_tls_impl() {}
-
 tcp::socket &session_tls_impl::socket() { return socket_.next_layer(); }
 
 void session_tls_impl::read_socket(

src/asio_client_session_tls_impl.h

@@ -42,10 +42,11 @@ using ssl_socket = boost::asio::ssl::stream<tcp::socket>;
 class session_tls_impl : public session_impl {
 public:
   session_tls_impl(boost::asio::io_service &io_service,
-                   boost::asio::ssl::context &tls_ctx,
-                   tcp::resolver::iterator endpoint_it);
+                   boost::asio::ssl::context &tls_ctx, const std::string &host,
+                   const std::string &service);
   virtual ~session_tls_impl();
 
+  virtual void start_connect(tcp::resolver::iterator endpoint_it);
   virtual tcp::socket &socket();
   virtual void read_socket(std::function<
       void(const boost::system::error_code &ec, std::size_t n)> h);

src/includes/nghttp2/asio_http2.h

@@ -337,11 +337,11 @@ class session_impl;
 
 class session {
 public:
+  session(boost::asio::io_service &io_service, const std::string &host,
+          const std::string &service);
   session(boost::asio::io_service &io_service,
-          boost::asio::ip::tcp::resolver::iterator endpoint_it);
-  session(boost::asio::io_service &io_service,
-          boost::asio::ssl::context &tls_context,
-          boost::asio::ip::tcp::resolver::iterator endpoint_it);
+          boost::asio::ssl::context &tls_context, const std::string &host,
+          const std::string &service);
   ~session();
 
   void on_connect(void_cb cb);
@@ -349,6 +349,8 @@ public:
 
   void shutdown();
 
+  boost::asio::io_service &io_service();
+
   request *submit(boost::system::error_code &ec, const std::string &method,
                   const std::string &uri, header_map h = {});
   request *submit(boost::system::error_code &ec, const std::string &method,