feat: add independent platform modules and multi-provider storage

storage/storage.go

@@ -0,0 +1,68 @@
+// Package storage defines streaming object storage; callers own returned bodies.
+package storage
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net/url"
+	"strings"
+	"time"
+	"unicode"
+	"unicode/utf8"
+)
+
+var ErrNotFound = errors.New("storage: object not found")
+var ErrTooLarge = errors.New("storage: object exceeds limit")
+
+type Info struct {
+	Key         string    `json:"key"`
+	Size        int64     `json:"size"`
+	ContentType string    `json:"contentType"`
+	ModifiedAt  time.Time `json:"modifiedAt"`
+}
+type Object struct {
+	Info
+	Body io.ReadCloser
+}
+type Store interface {
+	Put(context.Context, string, io.Reader, int64, string) (Info, error)
+	Get(context.Context, string) (Object, error)
+	Delete(context.Context, string) error
+}
+
+// Presigner is an optional capability. URLs grant temporary read access and
+// must not be logged. Providers may expire them earlier when credentials expire.
+type Presigner interface {
+	PresignGet(context.Context, string, time.Duration) (*url.URL, error)
+}
+
+func Check(ctx context.Context, key string) error {
+	if ctx == nil {
+		return errors.New("storage: nil context")
+	}
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	if key == "" || len(key) > 1024 || !utf8.ValidString(key) || strings.Contains(key, "\\") || strings.IndexFunc(key, unicode.IsControl) >= 0 {
+		return errors.New("storage: invalid key")
+	}
+	for _, part := range strings.Split(key, "/") {
+		if part == "" || part == "." || part == ".." {
+			return errors.New("storage: invalid key path")
+		}
+	}
+	return nil
+}
+
+type ContextReader struct {
+	Context context.Context
+	Reader  io.Reader
+}
+
+func (r ContextReader) Read(p []byte) (int, error) {
+	if err := r.Context.Err(); err != nil {
+		return 0, err
+	}
+	return r.Reader.Read(p)
+}