Initial QSfera import

Server/services/thumbnails/pkg/thumbnail/thumbnail.go

@@ -0,0 +1,131 @@
+package thumbnail
+
+import (
+	"bytes"
+	"image"
+	"mime"
+
+	"github.com/qsfera/server/pkg/log"
+	"github.com/qsfera/server/services/thumbnails/pkg/errors"
+	"github.com/qsfera/server/services/thumbnails/pkg/thumbnail/storage"
+)
+
+// Request bundles information needed to generate a thumbnail for a file
+type Request struct {
+	Resolution image.Rectangle
+	Encoder    Encoder
+	Generator  Generator
+	Checksum   string
+}
+
+// Manager is responsible for generating thumbnails
+type Manager interface {
+	// Generate creates a thumbnail and stores it.
+	// The function returns a key with which the actual file can be retrieved.
+	Generate(r Request, img any) (string, error)
+	// CheckThumbnail checks if a thumbnail with the requested attributes exists.
+	// The function will return a status if the file exists and the key to the file.
+	CheckThumbnail(r Request) (string, bool)
+	// GetThumbnail will load the thumbnail from the storage and return its content.
+	GetThumbnail(key string) ([]byte, error)
+}
+
+// NewSimpleManager creates a new instance of SimpleManager
+func NewSimpleManager(resolutions Resolutions, storage storage.Storage, logger log.Logger, maxInputWidth, maxInputHeight int) SimpleManager {
+	return SimpleManager{
+		storage:      storage,
+		logger:       logger,
+		resolutions:  resolutions,
+		maxDimension: image.Point{X: maxInputWidth, Y: maxInputHeight},
+	}
+}
+
+// SimpleManager is a simple implementation of Manager
+type SimpleManager struct {
+	storage      storage.Storage
+	logger       log.Logger
+	resolutions  Resolutions
+	maxDimension image.Point
+}
+
+// Generate creates a thumbnail and stores it
+func (s SimpleManager) Generate(r Request, img any) (string, error) {
+	var match image.Rectangle
+
+	inputDimensions, err := r.Generator.Dimensions(img)
+	if err != nil {
+		return "", err
+	}
+	match = s.resolutions.ClosestMatch(r.Resolution, inputDimensions)
+
+	// validate max input image dimensions - 6016x4000
+	if inputDimensions.Size().X > s.maxDimension.X || inputDimensions.Size().Y > s.maxDimension.Y {
+		return "", errors.ErrImageTooLarge
+	}
+
+	thumbnail, err := r.Generator.Generate(match, img)
+	if err != nil {
+		return "", err
+	}
+
+	buf := new(bytes.Buffer)
+	if err := r.Encoder.Encode(buf, thumbnail); err != nil {
+		return "", err
+	}
+
+	k := s.storage.BuildKey(mapToStorageRequest(r))
+	if err := s.storage.Put(k, buf.Bytes()); err != nil {
+		s.logger.Error().Err(err).Msg("could not store thumbnail")
+		return "", err
+	}
+	return k, nil
+}
+
+// CheckThumbnail checks if a thumbnail with the requested attributes exists.
+func (s SimpleManager) CheckThumbnail(r Request) (string, bool) {
+	k := s.storage.BuildKey(mapToStorageRequest(r))
+	return k, s.storage.Stat(k)
+}
+
+// GetThumbnail will load the thumbnail from the storage and return its content.
+func (s SimpleManager) GetThumbnail(key string) ([]byte, error) {
+	return s.storage.Get(key)
+}
+
+func mapToStorageRequest(r Request) storage.Request {
+	return storage.Request{
+		Checksum:       r.Checksum,
+		Resolution:     r.Resolution,
+		Types:          r.Encoder.Types(),
+		Characteristic: r.Generator.ProcessorID(),
+	}
+}
+
+// IsMimeTypeSupported validate if the mime type is supported
+func IsMimeTypeSupported(m string) bool {
+	mimeType, _, err := mime.ParseMediaType(m)
+	if err != nil {
+		return false
+	}
+	_, supported := SupportedMimeTypes[mimeType]
+	return supported
+}
+
+// PrepareRequest prepare the request based on image parameters
+func PrepareRequest(width, height int, tType, checksum, pID string) (Request, error) {
+	generator, err := GeneratorFor(tType, pID)
+	if err != nil {
+		return Request{}, err
+	}
+	encoder, err := EncoderForType(tType)
+	if err != nil {
+		return Request{}, err
+	}
+
+	return Request{
+		Resolution: image.Rect(0, 0, width, height),
+		Generator:  generator,
+		Encoder:    encoder,
+		Checksum:   checksum,
+	}, nil
+}