姚章浩
66 lines
1.8 KiB
Go
66 lines
1.8 KiB
Go
package outboundimage
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import (
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"context"
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"crypto/sha256"
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"encoding/hex"
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"errors"
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"path"
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"strings"
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"time"
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)
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type ObjectStore interface {
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Put(ctx context.Context, key string, data []byte, contentType string) error
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PresignGet(ctx context.Context, key string, ttl time.Duration) (string, error)
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}
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type HashPublisher struct {
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store ObjectStore
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prefix string
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ttl time.Duration
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}
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func NewHashPublisher(store ObjectStore, prefix string, ttl time.Duration) *HashPublisher {
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return &HashPublisher{store: store, prefix: strings.Trim(strings.TrimSpace(prefix), "/"), ttl: ttl}
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}
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func (p *HashPublisher) Publish(ctx context.Context, data []byte, contentType string) (string, error) {
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if p == nil || p.store == nil || len(data) == 0 || p.prefix == "" || p.ttl <= 0 {
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return "", errors.New("outbound image: invalid publisher configuration")
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}
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extension := imageExtension(contentType)
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if extension == "" {
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return "", errors.New("outbound image: unsupported image content type")
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}
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sum := sha256.Sum256(data)
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digest := hex.EncodeToString(sum[:])
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key := path.Join(p.prefix, digest[:2], digest+extension)
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if err := p.store.Put(ctx, key, data, contentType); err != nil {
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return "", errors.New("outbound image: publish object failed")
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}
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signedURL, err := p.store.PresignGet(ctx, key, p.ttl)
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if err != nil {
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return "", errors.New("outbound image: sign object URL failed")
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}
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if !strings.HasPrefix(strings.TrimSpace(signedURL), "https://") {
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return "", errors.New("outbound image: signed object URL must use HTTPS")
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}
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return signedURL, nil
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}
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func imageExtension(contentType string) string {
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switch strings.ToLower(strings.TrimSpace(strings.Split(contentType, ";")[0])) {
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case "image/jpeg", "image/jpg":
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return ".jpg"
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case "image/png":
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return ".png"
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case "image/webp":
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return ".webp"
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case "image/gif":
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return ".gif"
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default:
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return ""
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}
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}
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