Author: skaarj1989

README.md

@@ -39,7 +39,6 @@ Simple to use implementation of WebSockets for microcontrollers.
   - [Installation](#installation)
     - [Config.h](#configh)
     - [Physical connection](#physical-connection)
-  - [Prerequisite](#prerequisite)
   - [Usage examples](#usage-examples)
     - [Server](#server)
       - [Verify clients](#verify-clients)
@@ -111,20 +110,6 @@ If you have a **WeMos D1** in the size of **Arduino Uno** simply attaching a shi
 |          SCS          |           PIN 10            |        PIN 53         |
 |         SCLK          |           PIN 13            |        PIN 52         |
 
-## Prerequisite
-
-You need to provide your own implementation of `fetchRemoteIp`:
-
-```cpp
-// This is necessary because:
-// 1. Not every implementation of {Etherent/Wifi}Client implements remoteIP() function
-// 2. Arduino does not have <type_traits> which could allow use of SFINAE
-
-IPAddress fetchRemoteIp(const EthernetClient &client) {
-  return client.remoteIP();
-}
-```
-
 ## Usage examples
 
 ```cpp

src/Config.hpp

@@ -18,6 +18,6 @@
 //#define _DUMP_FRAME_DATA
 
 /** Maximum size of data buffer - frame payload (in bytes). */
-constexpr uint16_t kBufferMaxSize{512};
+constexpr uint16_t kBufferMaxSize{256};
 /** Maximum time to wait for endpoint response (in milliseconds). */
 constexpr uint16_t kTimeoutInterval{5000};

src/ExampleBoilerplate.hpp

@@ -35,17 +35,6 @@ using NetClient = EthernetClient;
 using NetServer = EthernetServer;
 #endif
 
-template <typename NetClient> IPAddress fetchRemoteIp(const NetClient &client) {
-#if (PLATFORM_ARCH == PLATFORM_ARCHITECTURE_ESP8266) &&                        \
-    (NETWORK_CONTROLLER == ETHERNET_CONTROLLER_W5X00)
-  // EthernetClient class in ESP8266 doesn't implement remoteIP()
-  return {};
-#else
-  // EthernetClient class is not "const correct"
-  return const_cast<NetClient &>(client).remoteIP();
-#endif
-}
-
 inline void setupNetwork() {
 #if NETWORK_CONTROLLER == NETWORK_CONTROLLER_WIFI
   //_SERIAL.setDebugOutput(true);

src/TypeTraits.hpp

@@ -0,0 +1,51 @@
+#pragma once
+
+#include "Platform.hpp"
+#if PLATFORM_ARCH != PLATFORM_ARCHITECTURE_AVR
+#  include <type_traits>
+#else
+namespace std {
+
+template <class _Ty, _Ty _Val> struct integral_constant {
+  static constexpr _Ty value = _Val;
+
+  using value_type = _Ty;
+  using type = integral_constant;
+
+  constexpr operator value_type() const noexcept { return value; }
+
+  constexpr value_type operator()() const noexcept { return value; }
+};
+
+template <bool _Val> using bool_constant = integral_constant<bool, _Val>;
+
+using true_type = bool_constant<true>;
+using false_type = bool_constant<false>;
+
+template <class, class> inline constexpr bool is_same_v = false;
+template <class _Ty> inline constexpr bool is_same_v<_Ty, _Ty> = true;
+
+template <class _Ty1, class _Ty2>
+struct is_same : bool_constant<is_same_v<_Ty1, _Ty2>> {};
+
+} // namespace std
+#endif
+
+#include <IPAddress.h>
+
+namespace net {
+
+template <typename T> struct has_remoteIP {
+  template <typename U> static constexpr std::false_type test(...) {
+    return {};
+  }
+  template <typename U>
+  static constexpr auto test(U *u) ->
+      typename std::is_same<IPAddress, decltype(u->remoteIP())>::type {
+    return {};
+  }
+
+  static constexpr bool value{test<T>(nullptr)};
+};
+
+} // namespace net

src/WebSocket.hpp

@@ -2,10 +2,10 @@
 
 /** @file */
 
+#include <Arduino.h>
 #include "Config.hpp"
 #include "Utility.hpp"
-#include <Arduino.h>
-#include <IPAddress.h>
+#include "TypeTraits.hpp"
 
 namespace net {
 
@@ -292,6 +292,14 @@ void encodeSecKey(const char *key, char output[]);
 /** @param[out] output Array of 4 elements (without NULL). */
 void generateMask(char output[]);
 
+template <typename NetClient>
+inline IPAddress fetchRemoteIp(const NetClient &client) {
+  if constexpr (has_remoteIP<NetClient>::value)
+    return client.remoteIP();
+  else
+    return {};
+}
+
 } // namespace net
 
 #include "WebSocket.inl"