func ImageData(storage store.ImageStore, gc groupcache.Context) ([]byte, error) {
c, ok := gc.(*CacheContext)
if !ok {
return nil, errors.New("invalid context")
}
var reader io.ReadCloser
var err error
defer func() {
if reader != nil {
reader.Close()
}
}()
resp, err := storage.Head(c.Bucket, c.ImageId)
if err != nil {
// Don't break on an error
log.Println(err)
}
reader, err = c.ReadModified(storage)
if err != nil {
reader, err = c.ReadOriginal(storage)
if err != nil {
return nil, err
}
} else {
log.Println("Retrieved resized image from S3")
return readImage(reader)
}
var buf io.Reader
if c.Width != 0 {
if resp != nil && resp.Header.Get("Content-Type") == "image/gif" {
buf, err = ResizeGif(reader, c)
} else {
buf, err = Resize(reader, c)
}
if err != nil {
return nil, err
}
}
result, err := readImage(buf)
if err != nil {
return nil, err
}
go func() {
err = c.WriteModified(result, storage)
if err != nil {
log.Printf("s3 upload: %s", err.Error())
}
}()
log.Println("Retrieved original and stored resized image in S3")
return result, err
}
func (c *CacheContext) ReadModified(s store.ImageStore) (io.ReadCloser, error) {
data, err := s.GetReader(c.Bucket, c.CacheKey())
if err != nil {
log.Printf("s3 download: %s", err.Error())
return nil, err
}
return data, err
}
func (c *CacheContext) ReadOriginal(s store.ImageStore) (io.ReadCloser, error) {
r, err := s.GetReader(c.Bucket, c.ImageId)
if err != nil {
log.Printf("s3 download: %s", err.Error())
return nil, err
}
return r, err
}
func (c *CacheContext) WriteModified(buf []byte, s store.ImageStore) error {
return s.Put(c.Bucket, c.CacheKey(), buf, http.DetectContentType(buf))
}