可靠性: 完善 R2 备份恢复与对象生命周期

2026-11-05 08:41:55 +08:00
parent 3e7719f200
commit 937e688cfa
32 changed files with 4151 additions and 231 deletions
@@ -0,0 +1,128 @@
+package storage
+
+import (
+	"fmt"
+	"net/url"
+	"strings"
+	"unicode"
+)
+
+// ObjectKeyFromCDNURL 将属于 cdnBase 的 HTTPS URL 转成原始 S3 对象 key。
+// cdnBase 可省略 scheme，也可带 base path。外站或不属于 base path 的 URL
+// 返回 owned=false 且不报错；格式非法或试图伪装路径的 URL 返回错误。
+func ObjectKeyFromCDNURL(rawURL, cdnBase string) (key string, owned bool, err error) {
+	base, err := parseCDNBase(cdnBase)
+	if err != nil {
+		return "", false, err
+	}
+	parsed, err := parseCDNURL(rawURL, false)
+	if err != nil {
+		return "", false, err
+	}
+	if !strings.EqualFold(parsed.Host, base.Host) {
+		return "", false, nil
+	}
+
+	basePath := base.Path
+	if basePath != "" {
+		if parsed.Path == basePath {
+			return "", false, fmt.Errorf("CDN URL does not contain an object key")
+		}
+		prefix := basePath + "/"
+		if !strings.HasPrefix(parsed.Path, prefix) {
+			return "", false, nil
+		}
+		key = strings.TrimPrefix(parsed.Path, prefix)
+	} else {
+		key = strings.TrimPrefix(parsed.Path, "/")
+	}
+	if key == "" {
+		return "", false, fmt.Errorf("CDN URL does not contain an object key")
+	}
+
+	// 只去掉 cdnBase 的路径和前导分隔符；不添加或移除 bucket，也不 Clean，
+	// 因而返回的解码路径仍是实际 S3 key。
+	return key, true, nil
+}
+
+func parseCDNBase(cdnBase string) (*url.URL, error) {
+	if cdnBase == "" {
+		return nil, fmt.Errorf("CDN base URL is empty")
+	}
+	rawBase := cdnBase
+	if strings.HasPrefix(rawBase, "//") {
+		rawBase = "https:" + rawBase
+	} else if !strings.Contains(rawBase, "://") {
+		rawBase = "https://" + rawBase
+	}
+	return parseCDNURL(rawBase, true)
+}
+
+func parseCDNURL(rawURL string, isBase bool) (*url.URL, error) {
+	if rawURL == "" {
+		return nil, fmt.Errorf("URL is empty")
+	}
+	if strings.Contains(rawURL, `\`) || containsControl(rawURL) {
+		return nil, fmt.Errorf("URL contains a backslash or control character")
+	}
+	parsed, err := url.Parse(rawURL)
+	if err != nil {
+		return nil, fmt.Errorf("parse URL: %w", err)
+	}
+	if !parsed.IsAbs() || !strings.EqualFold(parsed.Scheme, "https") || parsed.Host == "" ||
+		parsed.Hostname() == "" || parsed.Opaque != "" {
+		return nil, fmt.Errorf("URL must be an absolute HTTPS URL")
+	}
+	if parsed.User != nil {
+		return nil, fmt.Errorf("URL must not contain userinfo")
+	}
+	if parsed.RawQuery != "" || parsed.ForceQuery {
+		return nil, fmt.Errorf("URL must not contain a query")
+	}
+	if parsed.Fragment != "" || strings.Contains(rawURL, "#") {
+		return nil, fmt.Errorf("URL must not contain a fragment")
+	}
+
+	// 必须在 url.Parse 的 Path 解码之外检查 EscapedPath：编码斜杠在 Path 中
+	// 与普通分隔符无法区分，若放行会导致 CDN 与 S3 对 key 的解释不一致。
+	escapedPath := strings.ToLower(parsed.EscapedPath())
+	if strings.Contains(escapedPath, "%2f") || strings.Contains(escapedPath, "%5c") {
+		return nil, fmt.Errorf("URL path contains an encoded slash or backslash")
+	}
+	if strings.Contains(parsed.Path, `\`) || containsControl(parsed.Path) {
+		return nil, fmt.Errorf("URL path contains a backslash or control character")
+	}
+
+	if isBase && strings.HasSuffix(parsed.Path, "/") {
+		// 配置中的 CDN base 允许一个末尾斜杠；其余空路径段仍会被拒绝。
+		parsed.Path = strings.TrimSuffix(parsed.Path, "/")
+		parsed.RawPath = ""
+	}
+	if parsed.Path == "" {
+		if isBase {
+			return parsed, nil
+		}
+		return nil, fmt.Errorf("URL path is empty")
+	}
+	if !strings.HasPrefix(parsed.Path, "/") {
+		return nil, fmt.Errorf("URL path must be absolute")
+	}
+	for _, segment := range strings.Split(strings.TrimPrefix(parsed.Path, "/"), "/") {
+		if segment == "" {
+			return nil, fmt.Errorf("URL path contains an empty segment")
+		}
+		if segment == "." || segment == ".." {
+			return nil, fmt.Errorf("URL path contains a dot segment")
+		}
+	}
+	return parsed, nil
+}
+
+func containsControl(value string) bool {
+	for _, r := range value {
+		if unicode.IsControl(r) {
+			return true
+		}
+	}
+	return false
+}