Add external label service support to label maker (#913)

* Add external label service support to label maker

* Make external label service fetch to include user agent, limit response size and allow any image type

* Fix linting errors

* Fix "response body closed" closing the Body to soon

backend/app/api/handlers/v1/v1_ctrl_labelmaker.go

@@ -29,7 +29,7 @@ func generateOrPrint(ctrl *V1Controller, w http.ResponseWriter, r *http.Request,
 		_, err = w.Write([]byte("Printed!"))
 		return err
 	} else {
-		return labelmaker.GenerateLabel(w, &params)
+		return labelmaker.GenerateLabel(w, &params, ctrl.config)
 	}
 }
 

backend/internal/sys/config/conf.go

@@ -69,6 +69,8 @@ type LabelMakerConf struct {
 	PrintCommand          *string        `yaml:"string"`
 	AdditionalInformation *string        `yaml:"string"`
 	DynamicLength         bool           `yaml:"bool"      conf:"default:true"`
+	LabelServiceUrl       *string        `yaml:"label_service_url"`
+	LabelServiceTimeout   *time.Duration `yaml:"label_service_timeout"`
 }
 
 type BarcodeAPIConf struct {

backend/pkgs/labelmaker/labelmaker.go

@@ -9,6 +9,8 @@ import (
 	"image/png"
 	"io"
 	"log"
+	"net/http"
+	"net/url"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -138,11 +140,18 @@ func wrapText(text string, face font.Face, maxWidth int, maxHeight int, lineHeig
 	return wrappedLines, ""
 }
 
-func GenerateLabel(w io.Writer, params *GenerateParameters) error {
+func GenerateLabel(w io.Writer, params *GenerateParameters, cfg *config.Config) error {
 	if err := params.Validate(); err != nil {
 		return err
 	}
 
+	// If LabelServiceUrl is configured, fetch the label from the URL instead of generating it
+	if cfg != nil && cfg.LabelMaker.LabelServiceUrl != nil && *cfg.LabelMaker.LabelServiceUrl != "" {
+		log.Printf("LabelServiceUrl configured: %s", *cfg.LabelMaker.LabelServiceUrl)
+
+		return fetchLabelFromURL(w, *cfg.LabelMaker.LabelServiceUrl, params, cfg)
+	}
+
 	bodyText := params.DescriptionText
 	if params.AdditionalInformation != nil {
 		bodyText = bodyText + "\n" + *params.AdditionalInformation
@@ -218,7 +227,7 @@ func GenerateLabel(w io.Writer, params *GenerateParameters) error {
 	// Create the actual image with calculated height
 	bounds := image.Rect(0, 0, params.Width, requiredHeight)
 	img := image.NewRGBA(bounds)
-	draw.Draw(img, bounds, &image.Uniform{color.White}, image.Point{}, draw.Src)
+	draw.Draw(img, bounds, &image.Uniform{C: color.White}, image.Point{}, draw.Src)
 
 	// Draw QR code onto the image
 	draw.Draw(img,
@@ -279,6 +288,98 @@ func createContext(font *truetype.Font, size float64, img *image.RGBA, dpi float
 	return c
 }
 
+// fetchLabelFromURL fetches an image from the specified URL and writes it to the writer
+func fetchLabelFromURL(w io.Writer, serviceURL string, params *GenerateParameters, cfg *config.Config) error {
+	// Parse the base URL
+	baseURL, err := url.Parse(serviceURL)
+	if err != nil {
+		return fmt.Errorf("failed to parse service URL %s: %w", serviceURL, err)
+	}
+
+	// Build query parameters with the same attributes passed to print command
+	query := url.Values{}
+	query.Set("Width", fmt.Sprintf("%d", params.Width))
+	query.Set("Height", fmt.Sprintf("%d", params.Height))
+	query.Set("QrSize", fmt.Sprintf("%d", params.QrSize))
+	query.Set("Margin", fmt.Sprintf("%d", params.Margin))
+	query.Set("ComponentPadding", fmt.Sprintf("%d", params.ComponentPadding))
+	query.Set("TitleText", params.TitleText)
+	query.Set("TitleFontSize", fmt.Sprintf("%f", params.TitleFontSize))
+	query.Set("DescriptionText", params.DescriptionText)
+	query.Set("DescriptionFontSize", fmt.Sprintf("%f", params.DescriptionFontSize))
+	query.Set("Dpi", fmt.Sprintf("%f", params.Dpi))
+	query.Set("URL", params.URL)
+	query.Set("DynamicLength", fmt.Sprintf("%t", params.DynamicLength))
+
+	// Add AdditionalInformation if it exists
+	if params.AdditionalInformation != nil {
+		query.Set("AdditionalInformation", *params.AdditionalInformation)
+	}
+
+	// Set the query parameters
+	baseURL.RawQuery = query.Encode()
+	finalServiceURL := baseURL.String()
+
+	log.Printf("Fetching label from URL: %s", finalServiceURL)
+
+	// Use configured timeout or default to 30 seconds
+	timeout := 30 * time.Second
+	if cfg != nil && cfg.LabelMaker.LabelServiceTimeout != nil {
+		timeout = *cfg.LabelMaker.LabelServiceTimeout
+	}
+
+	// Create HTTP client with configurable timeout
+	client := &http.Client{
+		Timeout: timeout,
+	}
+
+	// Create HTTP request with custom headers
+	req, err := http.NewRequest("GET", finalServiceURL, nil)
+	if err != nil {
+		return fmt.Errorf("failed to create request for URL %s: %w", finalServiceURL, err)
+	}
+
+	// Set custom headers
+	req.Header.Set("User-Agent", "Homebox-LabelMaker/1.0")
+	req.Header.Set("Accept", "image/*")
+
+	// Make HTTP request to the label service
+	resp, err := client.Do(req)
+	if err != nil {
+		return fmt.Errorf("failed to fetch label from URL %s: %w", finalServiceURL, err)
+	}
+
+	// Check if the response status is OK
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("label service returned status %d for URL %s", resp.StatusCode, finalServiceURL)
+	}
+
+	// Check if the response is an image
+	contentType := resp.Header.Get("Content-Type")
+	if !strings.HasPrefix(contentType, "image/") {
+		return fmt.Errorf("label service returned invalid content type %s, expected image/*", contentType)
+	}
+
+	// Set default max response size (10MB)
+	maxResponseSize := int64(10 << 20)
+	if cfg != nil {
+		maxResponseSize = cfg.Web.MaxUploadSize << 20
+	}
+	limitedReader := io.LimitReader(resp.Body, maxResponseSize)
+
+	// Copy the response body to the writer
+	_, err = io.Copy(w, limitedReader)
+	if err != nil {
+		return fmt.Errorf("failed to write fetched label data: %w", err)
+	}
+
+	if err := resp.Body.Close(); err != nil {
+		log.Printf("failed to close response body: %v", err)
+	}
+
+	return nil
+}
+
 func PrintLabel(cfg *config.Config, params *GenerateParameters) error {
 	tmpFile := filepath.Join(os.TempDir(), fmt.Sprintf("label-%d.png", time.Now().UnixNano()))
 	f, err := os.OpenFile(tmpFile, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0600)
@@ -292,7 +393,7 @@ func PrintLabel(cfg *config.Config, params *GenerateParameters) error {
 		}
 	}()
 
-	err = GenerateLabel(f, params)
+	err = GenerateLabel(f, params, cfg)
 	if err != nil {
 		return err
 	}