feat: speedtest 网速测试服务（Go+Gin+SQLite，延迟/下载/上传 + 排行榜）

config/config.go

@@ -0,0 +1,156 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+
+	"github.com/BurntSushi/toml"
+)
+
+// DatabaseConfig holds database connection settings.
+type DatabaseConfig struct {
+	Driver string `toml:"driver"`
+	DSN    string `toml:"dsn"`
+}
+
+// WebConfig holds web server settings.
+type WebConfig struct {
+	// Addr 监听地址：以 / 开头视为 unix socket，否则视为 TCP 端口
+	Addr string `toml:"addr"`
+}
+
+// SpeedtestConfig holds speed test limits.
+type SpeedtestConfig struct {
+	MaxDownloadBytes int64 `toml:"max_download_bytes"` // 单次下载请求最大字节数
+	MaxUploadBytes   int64 `toml:"max_upload_bytes"`   // 单次上传请求最大字节数
+}
+
+// Config is the top-level configuration structure.
+type Config struct {
+	Database  DatabaseConfig  `toml:"database"`
+	Web       WebConfig       `toml:"web"`
+	Speedtest SpeedtestConfig `toml:"speedtest"`
+}
+
+func isWindows() bool { return runtime.GOOS == "windows" }
+
+func etcDir() string {
+	if isWindows() {
+		return WinEtcDir
+	}
+	return LinuxEtcDir
+}
+
+func baseDir() string {
+	if isWindows() {
+		return WinBaseDir
+	}
+	return LinuxBaseDir
+}
+
+func defaultDSN() string {
+	if isWindows() {
+		return DefaultDSNWin
+	}
+	return DefaultDSNLinux
+}
+
+// defaultConfig returns a fully populated Config with default values.
+func defaultConfig() *Config {
+	return &Config{
+		Database: DatabaseConfig{
+			Driver: DefaultDBDriver,
+			DSN:    defaultDSN(),
+		},
+		Web: WebConfig{
+			Addr: DefaultWebAddr,
+		},
+		Speedtest: SpeedtestConfig{
+			MaxDownloadBytes: DefaultMaxDownloadBytes,
+			MaxUploadBytes:   DefaultMaxUploadBytes,
+		},
+	}
+}
+
+// configFilePath returns the full path to the configuration file.
+// 支持通过环境变量 SPEEDTEST_CONFIG 覆盖（本地调试用）。
+func configFilePath() string {
+	if p := os.Getenv("SPEEDTEST_CONFIG"); p != "" {
+		return p
+	}
+	return filepath.Join(etcDir(), ConfigFileName)
+}
+
+// mergeDefaults overlays default values onto the loaded config for any zero/empty fields.
+func mergeDefaults(cfg *Config, defaults *Config) *Config {
+	if cfg.Database.Driver == "" {
+		cfg.Database.Driver = defaults.Database.Driver
+	}
+	if cfg.Database.DSN == "" {
+		cfg.Database.DSN = defaults.Database.DSN
+	}
+	if cfg.Web.Addr == "" {
+		cfg.Web.Addr = defaults.Web.Addr
+	}
+	if cfg.Speedtest.MaxDownloadBytes == 0 {
+		cfg.Speedtest.MaxDownloadBytes = defaults.Speedtest.MaxDownloadBytes
+	}
+	if cfg.Speedtest.MaxUploadBytes == 0 {
+		cfg.Speedtest.MaxUploadBytes = defaults.Speedtest.MaxUploadBytes
+	}
+	return cfg
+}
+
+// writeConfig writes the configuration to the given file path.
+func writeConfig(path string, cfg *Config) error {
+	dir := filepath.Dir(path)
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return fmt.Errorf("创建配置目录失败 %s: %w", dir, err)
+	}
+
+	f, err := os.Create(path)
+	if err != nil {
+		return fmt.Errorf("创建配置文件失败 %s: %w", path, err)
+	}
+	defer f.Close()
+
+	enc := toml.NewEncoder(f)
+	if err := enc.Encode(cfg); err != nil {
+		return fmt.Errorf("写入配置文件失败: %w", err)
+	}
+	return nil
+}
+
+// LoadConfig loads the configuration from disk.
+// If the configuration file does not exist, it creates one with default values.
+// If the file exists but has missing fields, they are filled with defaults and the file is updated.
+func LoadConfig() (*Config, error) {
+	path := configFilePath()
+	defaults := defaultConfig()
+
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		if mkErr := writeConfig(path, defaults); mkErr != nil {
+			return nil, mkErr
+		}
+		return defaults, nil
+	}
+
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("读取配置文件失败 %s: %w", path, err)
+	}
+
+	cfg := &Config{}
+	if err := toml.Unmarshal(data, cfg); err != nil {
+		return nil, fmt.Errorf("解析配置文件失败: %w", err)
+	}
+
+	merged := mergeDefaults(cfg, defaults)
+	if writeErr := writeConfig(path, merged); writeErr != nil {
+		return nil, writeErr
+	}
+
+	return merged, nil
+}