initial thumbnailing support

Server.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"log"
 	"net/http"
+	"regexp"
 	"strings"
 	"time"
 
@@ -92,6 +93,8 @@ const (
 	metadataUrlPrefix = `/info/`
 )
 
+var rxThumbUrl = regexp.MustCompile(`^/thumb/(.)/(.*)$`)
+
 func (this *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set(`Server`, SERVER_HEADER)
 	w.Header().Set(`Access-Control-Allow-Origin`, `*`) // Blanket allow CORS
@@ -110,6 +113,10 @@ func (this *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	} else if r.Method == "GET" && strings.HasPrefix(r.URL.Path, metadataUrlPrefix) {
 		this.handleInformation(w, r.URL.Path[len(metadataUrlPrefix):])
 
+	} else if r.Method == "GET" && rxThumbUrl.MatchString(r.URL.Path) {
+		parts := rxThumbUrl.FindStringSubmatch(r.URL.Path)
+		this.handleThumb(w, r, parts[1][0], parts[2])
+
 	} else if r.Method == "GET" && r.URL.Path == `/about` {
 		this.handleAbout(w)
 

thumb.go

@@ -0,0 +1,73 @@
+package contented
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"net/http"
+	"path/filepath"
+
+	"code.ivysaur.me/thumbnail"
+)
+
+func thumbnailer(t byte) (*thumbnail.Thumbnailer, error) {
+	// Modelled on what imgur.com offers
+	// @ref https://api.imgur.com/models/image#thumbs
+
+	const (
+		cacheSize = 1
+		outputFmt = thumbnail.OUTPUT_JPG
+		scaleFmt  = thumbnail.SCALEFMT_BILINEAR
+	)
+
+	switch t {
+	case 's':
+		return thumbnail.NewThumbnailerEx(90, 90, cacheSize, outputFmt, thumbnail.ASPECT_CROP_TO_DIMENSIONS, scaleFmt), nil
+	case 'b':
+		return thumbnail.NewThumbnailerEx(160, 160, cacheSize, outputFmt, thumbnail.ASPECT_CROP_TO_DIMENSIONS, scaleFmt), nil
+	case 't':
+		return thumbnail.NewThumbnailerEx(160, 160, cacheSize, outputFmt, thumbnail.ASPECT_RESPECT_MAX_DIMENSION_ONLY, scaleFmt), nil
+	case 'm':
+		return thumbnail.NewThumbnailerEx(340, 340, cacheSize, outputFmt, thumbnail.ASPECT_RESPECT_MAX_DIMENSION_ONLY, scaleFmt), nil
+	case 'l':
+		return thumbnail.NewThumbnailerEx(640, 640, cacheSize, outputFmt, thumbnail.ASPECT_RESPECT_MAX_DIMENSION_ONLY, scaleFmt), nil
+	case 'h':
+		return thumbnail.NewThumbnailerEx(1024, 1024, cacheSize, outputFmt, thumbnail.ASPECT_RESPECT_MAX_DIMENSION_ONLY, scaleFmt), nil
+	default:
+		return nil, errors.New("Unsupported thumbnail type (should be s/b/t/m/l/h)")
+	}
+}
+
+func (this *Server) handleThumb(w http.ResponseWriter, r *http.Request, thumbnailType byte, fileId string) {
+	err := this.handleThumbInternal(w, thumbnailType, fileId)
+	if err != nil {
+		log.Printf("%s Thumbnail failed: %s\n", this.remoteIP(r), err.Error())
+		http.Error(w, "Couldn't provide content", 500)
+	}
+}
+
+func (this *Server) handleThumbInternal(w http.ResponseWriter, thumbnailType byte, fileId string) error {
+	t, err := thumbnailer(thumbnailType)
+	if err != nil {
+		return err
+	}
+
+	// Load metadata
+	m, err := this.Metadata(fileId)
+	if err != nil {
+		return err
+	}
+
+	filePath := filepath.Join(this.opts.DataDirectory, m.FileHash)
+	thumb, err := t.RenderFile_NoCache_MimeType(filePath, m.MimeType)
+	if err != nil {
+		return err
+	}
+
+	w.Header().Set(`Content-Length`, fmt.Sprintf("%d", len(thumb)))
+	w.Header().Set(`Content-Type`, `image/jpeg`)
+	w.WriteHeader(200)
+	w.Write(thumb)
+
+	return nil
+}