/
gcsimage.go
153 lines (129 loc) · 2.92 KB
/
gcsimage.go
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package gcsimage
import (
"bytes"
"cloud.google.com/go/storage"
c "context"
"errors"
"fmt"
"github.com/disintegration/imaging"
"github.com/google/uuid"
"image"
"io/ioutil"
)
type Anchor int
const (
Center Anchor = iota
TopLeft
Top
TopRight
Left
Right
BottomLeft
Bottom
BottomRight
)
type Bucket struct {
handle *storage.BucketHandle
}
func InitBucket(ctx c.Context, bucketName string) (*Bucket, error) {
if len(bucketName) == 0 {
return nil, errors.New("bucket name is empty")
}
client, err := storage.NewClient(ctx)
if err != nil {
return nil, err
}
return &Bucket{
handle: client.Bucket(bucketName),
}, nil
}
func (b *Bucket) getByKey(ctx c.Context, key string) ([]byte, error, bool) {
reader, err := b.handle.Object(key).NewReader(ctx)
if err != nil {
return nil, err, false
}
defer reader.Close()
data, err := ioutil.ReadAll(reader)
if err != nil {
return nil, err, true
}
return data, nil, true
}
func (b *Bucket) Get(ctx c.Context, id string, anchor Anchor, width, height int) (data []byte, contentType string, err error) {
objHand := b.handle.Object(id)
attr, attrErr := objHand.Attrs(ctx)
if attrErr != nil {
err = attrErr
return
}
contentType = attr.ContentType
if contentType == "image/webp" || (width <= 0 && height <= 0) {
data, err, _ = b.getByKey(ctx, id)
return
}
key := fmt.Sprintf("%s-%d-%d", id, width, height)
isExist := false
data, err, isExist = b.getByKey(ctx, key)
if isExist {
return
}
reader, readErr := objHand.NewReader(ctx)
if readErr != nil {
err = readErr
return
}
defer reader.Close()
original, imgErr := imaging.Decode(reader, imaging.AutoOrientation(true))
if imgErr != nil {
err = imgErr
return
}
var modified *image.NRGBA
if width > 0 && height > 0 {
modified = imaging.Fill(original, width, height, imaging.Anchor(anchor), imaging.Lanczos)
} else {
modified = imaging.Resize(original, width, height, imaging.Lanczos)
}
buf := new(bytes.Buffer)
switch attr.ContentType {
case "image/png":
err = imaging.Encode(buf, modified, imaging.PNG)
case "image/jpeg":
err = imaging.Encode(buf, modified, imaging.JPEG)
case "image/gif":
err = imaging.Encode(buf, modified, imaging.GIF)
default:
msg := fmt.Sprintf("%s is not supported. Only image/png, image/jpeg, image/gif", attr.ContentType)
err = errors.New(msg)
}
if err != nil {
return
}
data = buf.Bytes()
saveErr := b.Save(ctx, key, data)
if saveErr != nil {
err = saveErr
return
}
return
}
func (b *Bucket) Add(ctx c.Context, data []byte) (string, error) {
id := uuid.New().String()
err := b.Save(ctx, id, data)
if err != nil {
return "", err
}
return id, nil
}
func (b *Bucket) Save(ctx c.Context, key string, data []byte) error {
if len(data) == 0 {
return errors.New("data is empty")
}
writer := b.handle.Object(key).NewWriter(ctx)
defer writer.Close()
_, errWrite := writer.Write(data)
if errWrite != nil {
return errWrite
}
return nil
}