examples/protocols/asio: use common network component

* Original commit: espressif/esp-idf@aa4a7804ec

examples/protocols/asio/udp_echo_server/main/Kconfig.projbuild

@@ -1,21 +1,9 @@
 menu "Example Configuration"
 
-    config ESP_WIFI_SSID
-        string "WiFi SSID"
-        default "myssid"
-        help
-            SSID (network name) for the example to connect to.
-
-    config ESP_WIFI_PASSWORD
-        string "WiFi Password"
-        default "mypassword"
-        help
-            WiFi password (WPA or WPA2) for the example to use.
-
     config EXAMPLE_PORT
-        string "asio example port number"
-        default "80"
+        string "Asio example port number"
+        default "2222"
         help
-            Port number used by ASIO example
+            Port number used by Asio example.
 
 endmenu

examples/protocols/asio/udp_echo_server/main/udp_echo_server.cpp

@@ -13,6 +13,12 @@
 
 #include "asio.hpp"
 
+#include "protocol_examples_common.h"
+#include "esp_event.h"
+#include "tcpip_adapter.h"
+#include "nvs_flash.h"
+
+
 using asio::ip::udp;
 
 class server
@@ -32,6 +38,7 @@ public:
         {
           if (!ec && bytes_recvd > 0)
           {
+            data_[bytes_recvd] = 0;
             std::cout << data_ << std::endl;
             do_send(bytes_recvd);
           }
@@ -59,8 +66,21 @@ private:
   char data_[max_length];
 };
 
-void asio_main()
+extern "C" void app_main()
 {
+    ESP_ERROR_CHECK(nvs_flash_init());
+    tcpip_adapter_init();
+    ESP_ERROR_CHECK(esp_event_loop_create_default());
+
+    /* This helper function configures Wi-Fi or Ethernet, as selected in menuconfig.
+     * Read "Establishing Wi-Fi or Ethernet Connection" section in
+     * examples/protocols/README.md for more information about this function.
+     */
+    ESP_ERROR_CHECK(example_connect());
+
+    /* This helper function configures blocking UART I/O */
+    ESP_ERROR_CHECK(example_configure_stdin_stdout());
+
     asio::io_context io_context;
 
     server s(io_context, std::atoi(CONFIG_EXAMPLE_PORT));