| """Module for range.""" | |
| from __future__ import annotations | |
| import logging | |
| logger = logging.getLogger(__name__) | |
| def _parse_suffix_range(end_s: str, file_size: int) -> tuple[int, int] | None: | |
| """处理后缀范围请求,如 bytes=-500""" | |
| try: | |
| suffix = int(end_s) | |
| except (ValueError, TypeError): | |
| return None | |
| if suffix <= 0: | |
| return None | |
| start = max(0, file_size - suffix) | |
| return (start, file_size - 1) | |
| def _parse_explicit_range(start_s: str, end_s: str, file_size: int) -> tuple[int, int] | None: | |
| """处理显式范围请求,如 bytes=0-499""" | |
| try: | |
| start = int(start_s) | |
| except (ValueError, TypeError): | |
| return None | |
| if start < 0: | |
| return None | |
| if end_s == "": | |
| end = file_size - 1 | |
| else: | |
| try: | |
| end = int(end_s) | |
| except (ValueError, TypeError): | |
| return None | |
| if end < start: | |
| return None | |
| end = min(end, file_size - 1) | |
| start = min(start, file_size - 1) | |
| return (start, end) | |
| def parse_range_header(range_header: str, file_size: int) -> tuple[int, int] | None: | |
| if not range_header or not range_header.startswith("bytes="): | |
| return None | |
| value = range_header[len("bytes=") :].strip() | |
| if "," in value: | |
| value = value.split(",", 1)[0].strip() | |
| if "-" not in value: | |
| return None | |
| start_s, end_s = value.split("-", 1) | |
| start_s = start_s.strip() | |
| end_s = end_s.strip() | |
| if start_s == "": | |
| return _parse_suffix_range(end_s, file_size) | |
| return _parse_explicit_range(start_s, end_s, file_size) | |