nepiedg
1eab1b99c1
- Rename all QINIU_* config/code/docs to OSS_* to match actual Alibaba Cloud OSS - Refactor upload module from internal/common/qiniu to internal/common/upload - Add backend proxy upload endpoint (POST /api/admin/marketing/upload) to avoid CORS - Auto-generate compressed thumbnail (800px, JPEG 80%) on admin image upload - Add dev-login endpoint (POST /api/v1/auth/dev-login) for H5 debugging - Add imageutil package for server-side image resizing Made-with: Cursor
73 lines
1.7 KiB
Go
73 lines
1.7 KiB
Go
package imageutil
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import (
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"bytes"
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"fmt"
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"image"
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"image/jpeg"
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"image/png"
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"io"
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"strings"
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"golang.org/x/image/draw"
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)
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type ResizeOptions struct {
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MaxWidth int
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Quality int // JPEG quality 1-100
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}
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func DefaultResizeOptions() ResizeOptions {
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return ResizeOptions{MaxWidth: 800, Quality: 80}
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}
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// GenerateThumbnail reads image data, resizes if wider than MaxWidth, and
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// re-encodes as JPEG. Returns the thumbnail bytes and whether the image
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// was actually resized (false if already small enough but still re-encoded).
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func GenerateThumbnail(data []byte, contentType string, opts ResizeOptions) ([]byte, error) {
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if opts.MaxWidth <= 0 {
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opts.MaxWidth = 800
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}
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if opts.Quality <= 0 || opts.Quality > 100 {
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opts.Quality = 80
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}
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src, err := decodeImage(bytes.NewReader(data), contentType)
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if err != nil {
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return nil, fmt.Errorf("decode image: %w", err)
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}
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bounds := src.Bounds()
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srcW := bounds.Dx()
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srcH := bounds.Dy()
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dstW := srcW
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dstH := srcH
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if srcW > opts.MaxWidth {
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dstW = opts.MaxWidth
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dstH = srcH * opts.MaxWidth / srcW
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}
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dst := image.NewRGBA(image.Rect(0, 0, dstW, dstH))
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draw.BiLinear.Scale(dst, dst.Bounds(), src, bounds, draw.Over, nil)
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var buf bytes.Buffer
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if err := jpeg.Encode(&buf, dst, &jpeg.Options{Quality: opts.Quality}); err != nil {
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return nil, fmt.Errorf("encode jpeg: %w", err)
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}
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return buf.Bytes(), nil
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}
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func decodeImage(r io.Reader, contentType string) (image.Image, error) {
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ct := strings.ToLower(contentType)
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switch {
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case strings.Contains(ct, "png"):
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return png.Decode(r)
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case strings.Contains(ct, "jpeg"), strings.Contains(ct, "jpg"):
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return jpeg.Decode(r)
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default:
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img, _, err := image.Decode(r)
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return img, err
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}
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}
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