Get Steam Game Installation location with C

vrchat_path.c

int main(int argc, char *argv[])
{
  char cmd_buffer[1024];
  char steamInstallPath[1024];
  HKEY hKey;
  if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, "SOFTWARE\\WOW6432Node\\Valve\\Steam", 0, KEY_READ, &hKey) == ERROR_SUCCESS)
  {
    DWORD dwType = REG_SZ;
    DWORD dwSize = sizeof(steamInstallPath);
    RegQueryValueEx(hKey, "InstallPath", NULL, &dwType, (LPBYTE)steamInstallPath, &dwSize);
    RegCloseKey(hKey);
  }
  else
  {
    printf("Error: Steam not found\n");
    system("pause");
    return 1;
  }
  printf("Steam install path: %s\n", steamInstallPath);
  char vrchatSteamId[] = "438100";
  char steamLibraryFoldersPath[1024];
  char vrchatSteamLibraryRootPath[1024];
  char vrchatInstallPath[1024];
  sprintf(steamLibraryFoldersPath, "%s\\steamapps\\libraryfolders.vdf", steamInstallPath);
  FILE *steamLibraryFoldersFile = fopen(steamLibraryFoldersPath, "r");
  if (steamLibraryFoldersFile == NULL)
  {
    printf("Error: Steam library folders not found\n");
    system("pause");
    return 1;
  }
  char line[1024];
  while (fgets(line, sizeof(line), steamLibraryFoldersFile))
  {
    if(strstr(line, "path") != NULL) 
    {
      char *token = strtok(line, "\"");
      token = strtok(NULL, "\"");
      token = strtok(NULL, "\"");
      token = strtok(NULL, "\"");
      sprintf(vrchatSteamLibraryRootPath, "%s", token);
      //replace "\\" to "\"
      for (int i = 0; i < strlen(vrchatSteamLibraryRootPath); i++)
      {
        if (vrchatSteamLibraryRootPath[i] == '\\' && vrchatSteamLibraryRootPath[i + 1] == '\\')
        {
          for (int j = i; j < strlen(vrchatSteamLibraryRootPath); j++)
          {
            vrchatSteamLibraryRootPath[j] = vrchatSteamLibraryRootPath[j + 1];
          }
        }
      }
      break;
    }
  }
  printf("VRChat steam library path: %s\n", vrchatSteamLibraryRootPath);
  char vrchatAppManifestPath[1024]; // appmanifest_438100.acf
  sprintf(vrchatAppManifestPath, "%s\\steamapps\\appmanifest_%s.acf", vrchatSteamLibraryRootPath, vrchatSteamId);
  printf("VRChat app manifest path: %s\n", vrchatAppManifestPath);
  
  FILE *vrchatAppManifestFile = fopen(vrchatAppManifestPath, "r");
  if (vrchatAppManifestFile == NULL)
  {
    printf("Error: VRChat not found\n");
    system("pause");
    return 1;
  }
  char line2[1024];
  while (fgets(line2, sizeof(line2), vrchatAppManifestFile))
  {
    if (strstr(line2, "installdir") != NULL)
    {
      char *token = strtok(line2, "\"");
      token = strtok(NULL, "\"");
      token = strtok(NULL, "\"");
      token = strtok(NULL, "\"");
      sprintf(vrchatInstallPath, "%s\\steamapps\\common\\%s", steamInstallPath, token);
      break;
    }
  }
  printf("VRChat install path: %s\n", vrchatInstallPath);
  return 0;
}

Python

import os
import re
import winreg

def get_steam_install_path():
    try:
        hkey = winreg.OpenKey(winreg.HKEY_LOCAL_MACHINE, r"SOFTWARE\WOW6432Node\Valve\Steam", 0, winreg.KEY_READ)
        steam_install_path, _ = winreg.QueryValueEx(hkey, "InstallPath")
        steam_install_path = os.path.normpath(steam_install_path)
        winreg.CloseKey(hkey)
        return steam_install_path
    except WindowsError:
        print("Error: Steam not found")
        input("Press any key to exit...")
        return None

def get_vrchat_install_path(steam_install_path):
    vrchat_steam_id = "438100"
    steam_library_folders_path = os.path.join(steam_install_path, "steamapps", "libraryfolders.vdf")

    try:
        with open(steam_library_folders_path, "r") as steam_library_folders_file:
            for line in steam_library_folders_file:
                match = re.search(r'"path"\s+"([^"]+)"', line)
                if match:
                    vrchat_steam_library_root_path = os.path.normpath(match.group(1))
                    break
    except IOError:
        print("Error: Steam library folders not found")
        input("Press any key to exit...")
        return None

    vrchat_app_manifest_path = os.path.join(vrchat_steam_library_root_path, "steamapps", f"appmanifest_{vrchat_steam_id}.acf")

    try:
        with open(vrchat_app_manifest_path, "r") as vrchat_app_manifest_file:
            for line in vrchat_app_manifest_file:
                match = re.search(r'"installdir"\s+"([^"]+)"', line)
                if match:
                    vrchat_install_path = os.path.join(steam_install_path, "steamapps", "common", match.group(1))
                    break
    except IOError:
        print("Error: VRChat not found")
        input("Press any key to exit...")
        return None

    return vrchat_install_path

if __name__ == "__main__":
    steam_install_path = get_steam_install_path()
    if steam_install_path:
        vrchat_install_path = get_vrchat_install_path(steam_install_path)
        if vrchat_install_path:
            print(f"VRChat install path: {vrchat_install_path}")