On the fly image conversion

internal/api/media.go

@@ -1,10 +1,17 @@
 package api
 
 import (
+	"bytes"
+	"errors"
+	"io/ioutil"
 	"net/http"
 	"os"
 	"path"
+	"strconv"
+	"time"
 
+	"github.com/davidbyttow/govips/v2/vips"
+	log "github.com/sirupsen/logrus"
 	"reichard.io/imagini/graph/model"
 )
 
@@ -23,21 +30,14 @@ func (api *API) mediaHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Acquire Width & Height Parameters
-	query := r.URL.Query()
-	width := query["width"]
-	height := query["height"]
-	_ = width
-	_ = height
-
-	// TODO: Caching & Resizing
-	//  - If both, force resize with new scale
-	//  - If one, scale resize proportionally
+	width, _ := strconv.Atoi(r.URL.Query().Get("width"))
 
 	// Pull out userID
 	authContext := r.Context().Value("auth").(*model.AuthContext)
 	rawUserID, _ := (*authContext.AccessToken).Get("sub")
 	userID := rawUserID.(string)
 
+	// TODO: Derive Cache & Width Location
 	// Derive Path
 	fileName := path.Base(r.URL.Path)
 	folderPath := path.Join("/" + api.Config.DataPath + "/media/" + userID)
@@ -46,10 +46,54 @@ func (api *API) mediaHandler(w http.ResponseWriter, r *http.Request) {
 	// Check if File Exists
 	_, err := os.Stat(mediaPath)
 	if os.IsNotExist(err) {
-		// TODO: Different HTTP Response Code?
-		w.WriteHeader(http.StatusMethodNotAllowed)
+		log.Warn("[media] Image does not exist on disk")
+		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}
 
-	http.ServeFile(w, r, mediaPath)
+	mediaFile, err := resizeAndConvertImage(mediaPath, width)
+	if err != nil {
+		log.Warn("[media] Image conversion failed:", err)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	// TODO: Cache mediaFile
+
+	http.ServeContent(w, r, fileName, time.Time{}, bytes.NewReader(mediaFile))
+}
+
+func resizeAndConvertImage(path string, desiredWidth int) ([]byte, error) {
+	inputImage, err := vips.NewImageFromFile(path)
+	if err != nil {
+		return nil, errors.New("[media] Unable to read image")
+	}
+
+	// If we're viewing full image, we want full quality
+	desiredQuality := 100
+
+	// Do we need to scale?
+	if desiredWidth != 0 && inputImage.Width() > desiredWidth {
+		desiredQuality = 50
+		desiredScale := float64(desiredWidth) / float64(inputImage.Width())
+		err := inputImage.Resize(desiredScale, vips.KernelLanczos3)
+		if err != nil {
+			return nil, errors.New("[media] Unable to resize")
+		}
+	} else if inputImage.Format() == vips.ImageTypeJPEG {
+		// Return raw file
+		return ioutil.ReadFile(path)
+	}
+
+	// Return non-converted but scaled image
+	if inputImage.Format() == vips.ImageTypeJPEG {
+		imageBytes, _, err := inputImage.ExportNative()
+		return imageBytes, err
+	}
+
+	// Convert
+	ep := vips.NewJpegExportParams()
+	ep.Quality = desiredQuality
+	imageBytes, _, err := inputImage.ExportJpeg(ep)
+	return imageBytes, err
 }

internal/api/media_item.go

@@ -1 +0,0 @@
-package api