Jigsaw1601 已修改 . 還原成這個修訂版本
1 file changed, 117 insertions
image_optimizer.go(檔案已創建)
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| 1 | + | // Package optimizer provides an interface for optimizing images. It provides both an in-process | |
| 2 | + | // optimizer that supports JPEG outputs, and an imaginary optimizer that supports WEBP outputs. | |
| 3 | + | package optimizer | |
| 4 | + | ||
| 5 | + | import ( | |
| 6 | + | "bytes" | |
| 7 | + | "context" | |
| 8 | + | "image" | |
| 9 | + | "image/jpeg" | |
| 10 | + | "io" | |
| 11 | + | ||
| 12 | + | _ "image/png" | |
| 13 | + | ||
| 14 | + | "github.com/hay-kot/httpkit/errtrace" | |
| 15 | + | "github.com/nfnt/resize" | |
| 16 | + | ) | |
| 17 | + | ||
| 18 | + | const ( | |
| 19 | + | MaxWidth = 800 | |
| 20 | + | ) | |
| 21 | + | ||
| 22 | + | type OptimizerResult struct { | |
| 23 | + | Body io.ReadCloser | |
| 24 | + | ContentType string | |
| 25 | + | ContentLength int64 | |
| 26 | + | Extension string | |
| 27 | + | } | |
| 28 | + | ||
| 29 | + | type Optimizer interface { | |
| 30 | + | Optimize(ctx context.Context, body io.Reader, contentType string) (*OptimizerResult, error) | |
| 31 | + | } | |
| 32 | + | ||
| 33 | + | var _ Optimizer = &InProcessOptimizer{} | |
| 34 | + | ||
| 35 | + | type InProcessOptimizer struct { | |
| 36 | + | sem chan struct{} | |
| 37 | + | } | |
| 38 | + | ||
| 39 | + | func NewInProcessOptimizer() *InProcessOptimizer { | |
| 40 | + | return &InProcessOptimizer{ | |
| 41 | + | sem: make(chan struct{}, 10), | |
| 42 | + | } | |
| 43 | + | } | |
| 44 | + | ||
| 45 | + | // UnlimitedConcurrency disables the semaphore, allowing unlimited concurrency. | |
| 46 | + | // This is useful for testing purposes, or if you have significant compute resources. | |
| 47 | + | func (i *InProcessOptimizer) UnlimitedConcurrency() { | |
| 48 | + | i.sem = nil | |
| 49 | + | } | |
| 50 | + | ||
| 51 | + | func (i *InProcessOptimizer) Optimize(ctx context.Context, body io.Reader, contentType string) (*OptimizerResult, error) { | |
| 52 | + | if i.sem != nil { | |
| 53 | + | // Acquire a semaphore slot | |
| 54 | + | i.sem <- struct{}{} | |
| 55 | + | ||
| 56 | + | // Release the semaphore slot | |
| 57 | + | defer func() { | |
| 58 | + | <-i.sem | |
| 59 | + | }() | |
| 60 | + | } | |
| 61 | + | ||
| 62 | + | // Check if the content type is supported | |
| 63 | + | if contentType == "image/webp" { | |
| 64 | + | buff := &bytes.Buffer{} | |
| 65 | + | nRead, err := io.Copy(buff, body) | |
| 66 | + | if err != nil { | |
| 67 | + | return nil, errtrace.Wrap(err) | |
| 68 | + | } | |
| 69 | + | ||
| 70 | + | return &OptimizerResult{ | |
| 71 | + | Body: io.NopCloser(buff), | |
| 72 | + | ContentType: contentType, | |
| 73 | + | ContentLength: nRead, | |
| 74 | + | Extension: "webp", | |
| 75 | + | }, nil | |
| 76 | + | } | |
| 77 | + | ||
| 78 | + | // Decode the image | |
| 79 | + | img, _, err := image.Decode(body) | |
| 80 | + | if err != nil { | |
| 81 | + | return nil, errtrace.Wrap(err) | |
| 82 | + | ||
| 83 | + | // This may not be necessary, keeping it to refer to later. | |
| 84 | + | /* // try webp, sometimes it's not detected correctly */ | |
| 85 | + | /* var webpErr error */ | |
| 86 | + | /* img, webpErr = webp.Decode(body) */ | |
| 87 | + | /* if webpErr != nil { */ | |
| 88 | + | /* return nil, errtrace.Wrapf(err, "failed to decode image: %s", webpErr.Error()) */ | |
| 89 | + | /* } */ | |
| 90 | + | } | |
| 91 | + | ||
| 92 | + | // Calculate the new dimensions while maintaining the aspect ratio | |
| 93 | + | newWidth := uint(MaxWidth) | |
| 94 | + | newHeight := uint(float64(newWidth) / float64(img.Bounds().Dx()) * float64(img.Bounds().Dy())) | |
| 95 | + | ||
| 96 | + | // Resize the image | |
| 97 | + | resizedImg := resize.Resize(newWidth, newHeight, img, resize.Lanczos3) | |
| 98 | + | ||
| 99 | + | // Encode the resized image as JPEG with 75% quality | |
| 100 | + | jpegOptions := jpeg.Options{ | |
| 101 | + | Quality: 75, | |
| 102 | + | } | |
| 103 | + | ||
| 104 | + | // Encode the resized image | |
| 105 | + | buf := new(bytes.Buffer) | |
| 106 | + | err = jpeg.Encode(buf, resizedImg, &jpegOptions) | |
| 107 | + | if err != nil { | |
| 108 | + | return nil, errtrace.Wrap(err) | |
| 109 | + | } | |
| 110 | + | ||
| 111 | + | return &OptimizerResult{ | |
| 112 | + | Body: io.NopCloser(buf), | |
| 113 | + | ContentType: "image/jpeg", | |
| 114 | + | ContentLength: int64(buf.Len()), | |
| 115 | + | Extension: "jpg", | |
| 116 | + | }, nil | |
| 117 | + | } | |
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