Add registry key to simplify launching

examples/send-presence/send-presence.c

@@ -95,8 +95,11 @@ static void gameLoop()
     }
 }
 
-int main()
+int main(int argc, char* argv[])
 {
+    /* This would typically be in an installer and/or wrapped to only run once */
+    Discord_Register(APPLICATION_ID);
+
     DiscordEventHandlers handlers;
     memset(&handlers, 0, sizeof(handlers));
     handlers.ready = handleDiscordReady;

include/discord-rpc.h

@@ -5,6 +5,12 @@
 extern "C" {
 #endif
 
+/* Registration */
+
+void Discord_Register(const char* applicationId);
+
+/* RPC */
+
 typedef struct DiscordRichPresence {
     const char* state;
     const char* details;

src/CMakeLists.txt

@@ -6,7 +6,7 @@ if (${ENABLE_IO_THREAD} EQUAL OFF)
     add_definitions(-DDISCORD_DISABLE_IO_THREAD)
 endif (${ENABLE_IO_THREAD} EQUAL OFF)
 
-set(BASE_RPC_SRC ${PROJECT_SOURCE_DIR}/include/discord-rpc.h discord-rpc.cpp rpc_connection.h rpc_connection.cpp serialization.h serialization.cpp connection.h backoff.h)
+set(BASE_RPC_SRC ${PROJECT_SOURCE_DIR}/include/discord-rpc.h discord-rpc.cpp discord-register.cpp rpc_connection.h rpc_connection.cpp serialization.h serialization.cpp connection.h backoff.h)
 
 if(WIN32)
     add_library(discord-rpc STATIC ${BASE_RPC_SRC} connection_win.cpp)

src/discord-register.cpp

@@ -0,0 +1,76 @@
+#include "discord-rpc.h"
+#include <stdio.h>
+
+#ifdef _WIN32
+#define WIN32_LEAN_AND_MEAN
+#define NOMCX
+#define NOSERVICE
+#define NOIME
+#include <windows.h>
+#include <Psapi.h>
+#include <Strsafe.h>
+#pragma comment(lib, "Psapi.lib")
+#endif
+
+void Discord_Register(const char* applicationId)
+{
+#ifdef _WIN32
+    // https://msdn.microsoft.com/en-us/library/aa767914(v=vs.85).aspx
+    // we want to register games so we can run them as discord-<appid>://
+    // Update the HKEY_CURRENT_USER, because it doesn't seem to require special permissions.
+
+    wchar_t appId[32];
+    MultiByteToWideChar(CP_UTF8, 0, applicationId, -1, appId, 32);
+
+    wchar_t exeFilePath[MAX_PATH];
+    GetModuleFileNameExW(GetCurrentProcess(), nullptr, exeFilePath, MAX_PATH);
+
+    wchar_t protocolName[64];
+    StringCbPrintfW(protocolName, sizeof(protocolName), L"discord-%s", appId);
+    wchar_t protocolDescription[128];
+    StringCbPrintfW(
+      protocolDescription, sizeof(protocolDescription), L"URL:Run game %s protocol", appId);
+    wchar_t urlProtocol = 0;
+    wchar_t openCommand[MAX_PATH + 8];
+    StringCbPrintfW(openCommand, sizeof(openCommand), L"\"%s\" \"%%1\"", exeFilePath);
+
+    wchar_t keyName[256];
+    StringCbPrintfW(keyName, sizeof(keyName), L"Software\\Classes\\%s", protocolName);
+    HKEY key;
+    auto status =
+      RegCreateKeyExW(HKEY_CURRENT_USER, keyName, 0, nullptr, 0, KEY_WRITE, nullptr, &key, nullptr);
+    if (status != ERROR_SUCCESS) {
+        fprintf(stderr, "Error creating key\n");
+        return;
+    }
+    DWORD len;
+    LSTATUS result;
+    len = lstrlenW(protocolDescription) + 1;
+    result =
+      RegSetKeyValueW(key, nullptr, nullptr, REG_SZ, protocolDescription, len * sizeof(wchar_t));
+    if (FAILED(result)) {
+        fprintf(stderr, "Error writing description\n");
+    }
+
+    len = lstrlenW(protocolDescription) + 1;
+    result = RegSetKeyValueW(key, nullptr, L"URL Protocol", REG_SZ, &urlProtocol, sizeof(wchar_t));
+    if (FAILED(result)) {
+        fprintf(stderr, "Error writing description\n");
+    }
+
+    len = lstrlenW(exeFilePath) + 1;
+    result =
+      RegSetKeyValueW(key, L"DefaultIcon", nullptr, REG_SZ, exeFilePath, len * sizeof(wchar_t));
+    if (FAILED(result)) {
+        fprintf(stderr, "Error writing icon\n");
+    }
+
+    len = lstrlenW(openCommand) + 1;
+    result = RegSetKeyValueW(
+      key, L"shell\\open\\command", nullptr, REG_SZ, openCommand, len * sizeof(wchar_t));
+    if (FAILED(result)) {
+        fprintf(stderr, "Error writing command\n");
+    }
+    RegCloseKey(key);
+#endif
+}