77 lines
1.8 KiB
Go
77 lines
1.8 KiB
Go
package thumbnails
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import (
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"bytes"
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"image"
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"time"
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"github.com/nfnt/resize"
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"github.com/owncloud/ocis-thumbnails/pkg/thumbnails/storage"
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)
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// ThumbnailContext bundles information needed to generate a thumbnail for afile
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type ThumbnailContext struct {
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Width int
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Height int
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ImagePath string
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Encoder Encoder
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ETag string
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}
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// Manager is responsible for generating thumbnails
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type Manager interface {
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// Get will return a thumbnail for a file
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Get(ThumbnailContext, image.Image) ([]byte, error)
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GetStored(ThumbnailContext) []byte
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}
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// SimpleManager is a simple implementation of Manager
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type SimpleManager struct {
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Storage storage.Storage
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}
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// Get implements the Get Method of Manager
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func (s SimpleManager) Get(ctx ThumbnailContext, img image.Image) ([]byte, error) {
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thumbnail := s.generate(ctx, img)
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key := s.Storage.BuildKey(mapToStorageContext(ctx))
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buf := new(bytes.Buffer)
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err := ctx.Encoder.Encode(buf, thumbnail)
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if err != nil {
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return nil, err
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}
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bytes := buf.Bytes()
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s.Storage.Set(key, bytes)
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return bytes, nil
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}
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// GetStored tries to get the stored thumbnail and return it.
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// If there is no cached thumbnail it will return nil
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func (s SimpleManager) GetStored(ctx ThumbnailContext) []byte {
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key := s.Storage.BuildKey(mapToStorageContext(ctx))
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stored := s.Storage.Get(key)
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if stored == nil {
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return nil
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}
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return stored
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}
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func (s SimpleManager) generate(ctx ThumbnailContext, img image.Image) image.Image {
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// TODO: remove, just for demo purposes
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time.Sleep(time.Second * 2)
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thumbnail := resize.Thumbnail(uint(ctx.Width), uint(ctx.Height), img, resize.Lanczos2)
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return thumbnail
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}
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func mapToStorageContext(ctx ThumbnailContext) storage.StorageContext {
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sCtx := storage.StorageContext{
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ETag: ctx.ETag,
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Width: ctx.Width,
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Height: ctx.Height,
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Types: ctx.Encoder.Types(),
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}
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return sCtx
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}
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