feat: allow custom QR login output

README.md

@@ -41,6 +41,25 @@ func main() {
 
 `auth.json` 包含 `serviceToken`、`passToken`、`ssecurity` 等敏感认证数据。库写入该文件时使用 `0600` 权限；请保持此权限，并且不要将该文件提交到版本库。
 
+Web/GUI 应用可通过 `WithQRWriter` 接收登录输出，再将其展示给用户：
+
+```go
+var loginOutput bytes.Buffer
+client, err := mijia.NewClient("", mijia.WithQRWriter(&loginOutput))
+if err != nil {
+	return err
+}
+
+if _, err := client.Login(ctx); err != nil {
+	return err
+}
+
+// loginOutput 包含二维码 URL 和终端二维码文本，可交给 Web/GUI 展示层。
+renderLoginOutput(loginOutput.String())
+```
+
+Writer 接收的内容包含登录二维码 URL，属于敏感登录信息；调用方不得将其写入日志、监控事件或其他持久化记录。
+
 ## 底层 API
 
 以下示例展示设备、属性和 action 的直接调用。`GetDevices` 的 `homeID` 传空字符串时查询所有家庭。

client.go

@@ -36,6 +36,17 @@ func WithHTTPClient(httpClient *http.Client) Option {
 	}
 }
 
+// WithQRWriter configures where QR login output is written.
+func WithQRWriter(writer io.Writer) Option {
+	return func(client *Client) error {
+		if writer == nil {
+			return fmt.Errorf("QR writer must not be nil")
+		}
+		client.qrWriter = writer
+		return nil
+	}
+}
+
 type Client struct {
 	authPath        string
 	authMu          sync.RWMutex

client_test.go

@@ -12,12 +12,41 @@ import (
 	"net/http/cookiejar"
 	"net/http/httptest"
 	"net/url"
+	"os"
 	"strings"
 	"sync"
 	"testing"
 	"time"
 )
 
+func TestWithQRWriter(t *testing.T) {
+	var output bytes.Buffer
+	client, err := NewClient(t.TempDir(), WithQRWriter(&output))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if client.qrWriter != &output {
+		t.Fatalf("qrWriter = %v, want custom writer", client.qrWriter)
+	}
+}
+
+func TestWithQRWriterRejectsNil(t *testing.T) {
+	_, err := NewClient(t.TempDir(), WithQRWriter(nil))
+	if err == nil || err.Error() != "QR writer must not be nil" {
+		t.Fatalf("error = %v, want QR writer must not be nil", err)
+	}
+}
+
+func TestDefaultQRWriterIsStdout(t *testing.T) {
+	client, err := NewClient(t.TempDir())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if client.qrWriter != os.Stdout {
+		t.Fatalf("qrWriter = %v, want os.Stdout", client.qrWriter)
+	}
+}
+
 func TestRequestEncryptedPostAndPlainResponse(t *testing.T) {
 	var received url.Values
 	handlerErrors := make(chan error, 1)