chenhg5/cc-connect · error

%s: aes_key hex inside base64: %w

Error message

%s: aes_key hex inside base64: %w

What it means

Inside parseAesKey, the base64-decoded aes_key was 32 bytes of ASCII that matched the hex pattern, but hex.DecodeString still failed — theoretically impossible after regex validation, so this indicates corrupt data or a regex/decoder mismatch on the CDN media key.

Source

Thrown at platform/weixin/cdn.go:104

	}
	return pkcs7Unpad(out, aes.BlockSize)
}

// parseAesKey decodes CDNMedia.aes_key: base64(raw 16 bytes) or base64(32-char hex ASCII) → 16 bytes.
func parseAesKey(aesKeyBase64, label string) ([]byte, error) {
	decoded, err := base64.StdEncoding.DecodeString(strings.TrimSpace(aesKeyBase64))
	if err != nil {
		return nil, fmt.Errorf("%s: aes_key base64: %w", label, err)
	}
	if len(decoded) == 16 {
		return decoded, nil
	}
	if len(decoded) == 32 {
		s := string(decoded)
		if hex32RE.MatchString(s) {
			k, err := hex.DecodeString(s)
			if err != nil {
				return nil, fmt.Errorf("%s: aes_key hex inside base64: %w", label, err)
			}
			return k, nil
		}
	}
	return nil, fmt.Errorf("%s: aes_key must be 16 raw bytes or 32-char hex (base64-wrapped), got %d bytes after base64", label, len(decoded))
}

func buildCdnDownloadURL(encryptedQueryParam, cdnBase string) string {
	return fmt.Sprintf("%s/download?encrypted_query_param=%s",
		strings.TrimRight(cdnBase, "/"),
		url.QueryEscape(encryptedQueryParam))
}

func buildCdnUploadURL(cdnBase, uploadParam, filekey string) string {
	return fmt.Sprintf("%s/upload?encrypted_query_param=%s&filekey=%s",
		strings.TrimRight(cdnBase, "/"),
		url.QueryEscape(uploadParam),
		url.QueryEscape(filekey))

View on GitHub (pinned to 4000b2338a)

Solutions

1. Log the offending decoded string (it is key material metadata, not a secret payload) to see why hex decoding rejects it
2. Tighten or replace hex32RE so it exactly matches hex.DecodeString's accepted alphabet (0-9a-f, case handling)

When it happens

Trigger: Thrown at platform/weixin/cdn.go:104 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/26b05f15924f9637. Report an issue: GitHub.