feat: add useagent option

option.go

@@ -2,14 +2,16 @@ package osm
 
 // Opts holds configuration options for requests.
 type Opts struct {
-	Locale string // Locale specifies the language for the response.
+	Locale    string // Locale specifies the language for the response.
+	UserAgent string // UserAgent specifies the User-Agent header for the request.
 }
 
 type optFunc func(*Opts)
 
 // DefaultOpts provides the default options for requests.
 var DefaultOpts = Opts{
-	Locale: "en", // Default locale is English.
+	Locale:    "en",     // Default locale is English.
+	UserAgent: "Chrome", // Default User-Agent is Chrome.
 }
 
 // WithLocale returns an optFunc that sets the locale option.
@@ -20,6 +22,14 @@ func WithLocale(locale string) optFunc {
 	}
 }
 
+// WithUserAgent returns an optFunc that sets the User-Agent option.
+// userAgent specifies the User-Agent header for the request.
+func WithUserAgent(userAgent string) optFunc {
+	return func(o *Opts) {
+		o.UserAgent = userAgent
+	}
+}
+
 func mergeOpts(optsList []optFunc) *Opts {
 	o := &Opts{}
 	for _, opt := range optsList {
@@ -28,5 +38,8 @@ func mergeOpts(optsList []optFunc) *Opts {
 	if o.Locale == "" {
 		o.Locale = DefaultOpts.Locale
 	}
+	if o.UserAgent == "" {
+		o.UserAgent = DefaultOpts.UserAgent
+	}
 	return o
 }

req.go

@@ -16,6 +16,7 @@ func runRequest[T any](ctx context.Context, url string, opts ...optFunc) (*T, er
 		return nil, err
 	}
 	req.Header.Set("Accept-Language", o.Locale)
+	req.Header.Set("User-Agent", o.UserAgent)
 	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		return nil, err