|
| 1 | +""" |
| 2 | +Download ranges of files over remote http. |
| 3 | +""" |
| 4 | + |
| 5 | +from collections import namedtuple |
| 6 | + |
| 7 | +from pip._vendor import requests |
| 8 | + |
| 9 | +from pip._internal.utils.typing import MYPY_CHECK_RUNNING |
| 10 | +from pip._internal.utils.urls import get_url_scheme |
| 11 | + |
| 12 | +if MYPY_CHECK_RUNNING: |
| 13 | + from typing import Any, Optional |
| 14 | + |
| 15 | + |
| 16 | +def url_is_remote(url): |
| 17 | + # type: (str) -> bool |
| 18 | + return get_url_scheme(url) in ['http', 'https'] |
| 19 | + |
| 20 | + |
| 21 | +class Url(namedtuple('Url', ['url'])): |
| 22 | + |
| 23 | + def __new__(cls, url): |
| 24 | + # type: (str) -> Url |
| 25 | + assert url_is_remote(url) |
| 26 | + return super(Url, cls).__new__(cls, url) |
| 27 | + |
| 28 | + |
| 29 | +class HttpFileRequest(namedtuple('HttpFileRequest', ['url'])): |
| 30 | + pass |
| 31 | + |
| 32 | + |
| 33 | +class Size(namedtuple('Size', ['size'])): |
| 34 | + def __new__(cls, size=0): |
| 35 | + # type: (int) -> Size |
| 36 | + assert size >= 0 |
| 37 | + return super(Size, cls).__new__(cls, size) |
| 38 | + |
| 39 | + def __add__(self, other): |
| 40 | + # type: (Any) -> Size |
| 41 | + assert isinstance(other, type(self)) |
| 42 | + return Size(self.size + other.size) |
| 43 | + |
| 44 | + def __sub__(self, other): |
| 45 | + # type: (Any) -> Size |
| 46 | + assert isinstance(other, type(self)) |
| 47 | + return Size(self.size - other.size) |
| 48 | + |
| 49 | + def __lt__(self, other): |
| 50 | + # type: (Any) -> bool |
| 51 | + assert isinstance(other, type(self)) |
| 52 | + return self.size < other.size |
| 53 | + |
| 54 | + def __le__(self, other): |
| 55 | + # type: (Any) -> bool |
| 56 | + assert isinstance(other, type(self)) |
| 57 | + return self.size <= other.size |
| 58 | + |
| 59 | + def __gt__(self, other): |
| 60 | + # type: (Any) -> bool |
| 61 | + assert isinstance(other, type(self)) |
| 62 | + return self.size > other.size |
| 63 | + |
| 64 | + def __ge__(self, other): |
| 65 | + # type: (Any) -> bool |
| 66 | + assert isinstance(other, type(self)) |
| 67 | + return self.size >= other.size |
| 68 | + |
| 69 | + |
| 70 | +class ByteRange(namedtuple('ByteRange', ['start', 'end'])): |
| 71 | + def __new__(cls, start, end): |
| 72 | + # type: (Size, Size) -> ByteRange |
| 73 | + assert end >= start |
| 74 | + return super(ByteRange, cls).__new__(cls, start, end) |
| 75 | + |
| 76 | + def as_bytes_range_header(self): |
| 77 | + # type: () -> str |
| 78 | + return "bytes={start}-{end}".format( |
| 79 | + start=self.start.size, |
| 80 | + # NB: The byte ranges accepted here are inclusive, so remove one |
| 81 | + # from the end. |
| 82 | + end=(self.end.size - 1)) |
| 83 | + |
| 84 | + def size_diff(self): |
| 85 | + # type: () -> Size |
| 86 | + return self.end - self.start |
| 87 | + |
| 88 | + |
| 89 | +class BytesRangeRequest(namedtuple('BytesRangeRequest', ['start', 'end'])): |
| 90 | + def __new__(cls, start, end): |
| 91 | + # type: (Optional[Size], Optional[Size]) -> BytesRangeRequest |
| 92 | + if (start is not None) and (end is not None): |
| 93 | + assert end >= start |
| 94 | + return super(BytesRangeRequest, cls).__new__(cls, start, end) |
| 95 | + |
| 96 | + def get_byte_range(self, size): |
| 97 | + # type: (Size) -> ByteRange |
| 98 | + if self.start is None: |
| 99 | + start = 0 |
| 100 | + else: |
| 101 | + assert self.start <= size, "???/start={start},size={size}".format( |
| 102 | + start=self.start, size=size) |
| 103 | + start = self.start.size |
| 104 | + |
| 105 | + if self.end is None: |
| 106 | + end = size.size |
| 107 | + else: |
| 108 | + assert self.end <= size |
| 109 | + end = self.end.size |
| 110 | + |
| 111 | + return ByteRange(start=Size(start), end=Size(end)) |
| 112 | + |
| 113 | + |
| 114 | +class HttpFile(namedtuple('HttpFile', ['url', 'size'])): |
| 115 | + pass |
| 116 | + |
| 117 | + |
| 118 | +class Context(object): |
| 119 | + |
| 120 | + def __init__(self, session=None): |
| 121 | + # type: (Optional[requests.Session]) -> None |
| 122 | + self.session = session or requests.Session() |
| 123 | + |
| 124 | + def head(self, request): |
| 125 | + # type: (HttpFileRequest) -> HttpFile |
| 126 | + resp = self.session.head(request.url.url) |
| 127 | + resp.raise_for_status() |
| 128 | + assert ( |
| 129 | + "bytes" in resp.headers["Accept-Ranges"] |
| 130 | + ), "???/bytes was not found in range headers" |
| 131 | + content_length = int(resp.headers["Content-Length"]) |
| 132 | + return HttpFile(url=request.url, size=Size(content_length)) |
| 133 | + |
| 134 | + def range_request(self, http_file, request): |
| 135 | + # type: (HttpFile, BytesRangeRequest) -> bytes |
| 136 | + byte_range = request.get_byte_range(http_file.size) |
| 137 | + resp = self.session.get( |
| 138 | + http_file.url.url, |
| 139 | + headers={"Range": byte_range.as_bytes_range_header()}) |
| 140 | + resp.raise_for_status() |
| 141 | + |
| 142 | + if Size(len(resp.content)) == http_file.size: |
| 143 | + # This request for the full URL contents is cached, and we should |
| 144 | + # return just the requested byte range. |
| 145 | + start = byte_range.start.size |
| 146 | + end = byte_range.end.size |
| 147 | + response_bytes = resp.content[start:end] |
| 148 | + else: |
| 149 | + response_bytes = resp.content |
| 150 | + |
| 151 | + size_diff = byte_range.size_diff() |
| 152 | + assert ( |
| 153 | + Size(len(response_bytes)) == size_diff |
| 154 | + ), ("???/response should have been length {}, but got (size {}):\n{!r}" |
| 155 | + .format(size_diff, len(response_bytes), response_bytes)) |
| 156 | + return response_bytes |
0 commit comments