JezK
Edit File: link.py
import functools import itertools import logging import os import posixpath import re import urllib.parse from dataclasses import dataclass from typing import ( TYPE_CHECKING, Any, Dict, List, Mapping, NamedTuple, Optional, Tuple, Union, ) from pip._internal.utils.deprecation import deprecated from pip._internal.utils.filetypes import WHEEL_EXTENSION from pip._internal.utils.hashes import Hashes from pip._internal.utils.misc import ( pairwise, redact_auth_from_url, split_auth_from_netloc, splitext, ) from pip._internal.utils.models import KeyBasedCompareMixin from pip._internal.utils.urls import path_to_url, url_to_path if TYPE_CHECKING: from pip._internal.index.collector import IndexContent logger = logging.getLogger(__name__) # Order matters, earlier hashes have a precedence over later hashes for what # we will pick to use. _SUPPORTED_HASHES = ("sha512", "sha384", "sha256", "sha224", "sha1", "md5") @dataclass(frozen=True) class LinkHash: """Links to content may have embedded hash values. This class parses those. `name` must be any member of `_SUPPORTED_HASHES`. This class can be converted to and from `ArchiveInfo`. While ArchiveInfo intends to be JSON-serializable to conform to PEP 610, this class contains the logic for parsing a hash name and value for correctness, and then checking whether that hash conforms to a schema with `.is_hash_allowed()`.""" name: str value: str _hash_re = re.compile( # NB: we do not validate that the second group (.*) is a valid hex # digest. Instead, we simply keep that string in this class, and then check it # against Hashes when hash-checking is needed. This is easier to debug than # proactively discarding an invalid hex digest, as we handle incorrect hashes # and malformed hashes in the same place. r"({choices})=(.*)".format( choices="|".join(re.escape(hash_name) for hash_name in _SUPPORTED_HASHES) ), ) def __post_init__(self) -> None: assert self._hash_re.match(f"{self.name}={self.value}") @classmethod @functools.lru_cache(maxsize=None) def split_hash_name_and_value(cls, url: str) -> Optional["LinkHash"]: """Search a string for a checksum algorithm name and encoded output value.""" match = cls._hash_re.search(url) if match is None: return None name, value = match.groups() return cls(name=name, value=value) def as_dict(self) -> Dict[str, str]: return {self.name: self.value} def as_hashes(self) -> Hashes: """Return a Hashes instance which checks only for the current hash.""" return Hashes({self.name: [self.value]}) def is_hash_allowed(self, hashes: Optional[Hashes]) -> bool: """ Return True if the current hash is allowed by `hashes`. """ if hashes is None: return False return hashes.is_hash_allowed(self.name, hex_digest=self.value) def _clean_url_path_part(part: str) -> str: """ Clean a "part" of a URL path (i.e. after splitting on "@" characters). """ # We unquote prior to quoting to make sure nothing is double quoted. return urllib.parse.quote(urllib.parse.unquote(part)) def _clean_file_url_path(part: str) -> str: """ Clean the first part of a URL path that corresponds to a local filesystem path (i.e. the first part after splitting on "@" characters). """ # We unquote prior to quoting to make sure nothing is double quoted. # Also, on Windows the path part might contain a drive letter which # should not be quoted. On Linux where drive letters do not # exist, the colon should be quoted. We rely on urllib.request # to do the right thing here. return urllib.request.pathname2url(urllib.request.url2pathname(part)) # percent-encoded: / _reserved_chars_re = re.compile("(@|%2F)", re.IGNORECASE) def _clean_url_path(path: str, is_local_path: bool) -> str: """ Clean the path portion of a URL. """ if is_local_path: clean_func = _clean_file_url_path else: clean_func = _clean_url_path_part # Split on the reserved characters prior to cleaning so that # revision strings in VCS URLs are properly preserved. parts = _reserved_chars_re.split(path) cleaned_parts = [] for to_clean, reserved in pairwise(itertools.chain(parts, [""])): cleaned_parts.append(clean_func(to_clean)) # Normalize %xx escapes (e.g. %2f -> %2F) cleaned_parts.append(reserved.upper()) return "".join(cleaned_parts) def _ensure_quoted_url(url: str) -> str: """ Make sure a link is fully quoted. For example, if ' ' occurs in the URL, it will be replaced with "%20", and without double-quoting other characters. """ # Split the URL into parts according to the general structure # `scheme://netloc/path;parameters?query#fragment`. result = urllib.parse.urlparse(url) # If the netloc is empty, then the URL refers to a local filesystem path. is_local_path = not result.netloc path = _clean_url_path(result.path, is_local_path=is_local_path) return urllib.parse.urlunparse(result._replace(path=path)) class Link(KeyBasedCompareMixin): """Represents a parsed link from a Package Index's simple URL""" __slots__ = [ "_parsed_url", "_url", "_hashes", "comes_from", "requires_python", "yanked_reason", "dist_info_metadata", "cache_link_parsing", "egg_fragment", ] def __init__( self, url: str, comes_from: Optional[Union[str, "IndexContent"]] = None, requires_python: Optional[str] = None, yanked_reason: Optional[str] = None, dist_info_metadata: Optional[str] = None, cache_link_parsing: bool = True, hashes: Optional[Mapping[str, str]] = None, ) -> None: """ :param url: url of the resource pointed to (href of the link) :param comes_from: instance of IndexContent where the link was found, or string. :param requires_python: String containing the `Requires-Python` metadata field, specified in PEP 345. This may be specified by a data-requires-python attribute in the HTML link tag, as described in PEP 503. :param yanked_reason: the reason the file has been yanked, if the file has been yanked, or None if the file hasn't been yanked. This is the value of the "data-yanked" attribute, if present, in a simple repository HTML link. If the file has been yanked but no reason was provided, this should be the empty string. See PEP 592 for more information and the specification. :param dist_info_metadata: the metadata attached to the file, or None if no such metadata is provided. This is the value of the "data-dist-info-metadata" attribute, if present, in a simple repository HTML link. This may be parsed into its own `Link` by `self.metadata_link()`. See PEP 658 for more information and the specification. :param cache_link_parsing: A flag that is used elsewhere to determine whether resources retrieved from this link should be cached. PyPI URLs should generally have this set to False, for example. :param hashes: A mapping of hash names to digests to allow us to determine the validity of a download. """ # url can be a UNC windows share if url.startswith("\\\\"): url = path_to_url(url) self._parsed_url = urllib.parse.urlsplit(url) # Store the url as a private attribute to prevent accidentally # trying to set a new value. self._url = url link_hash = LinkHash.split_hash_name_and_value(url) hashes_from_link = {} if link_hash is None else link_hash.as_dict() if hashes is None: self._hashes = hashes_from_link else: self._hashes = {**hashes, **hashes_from_link} self.comes_from = comes_from self.requires_python = requires_python if requires_python else None self.yanked_reason = yanked_reason self.dist_info_metadata = dist_info_metadata super().__init__(key=url, defining_class=Link) self.cache_link_parsing = cache_link_parsing self.egg_fragment = self._egg_fragment() @classmethod def from_json( cls, file_data: Dict[str, Any], page_url: str, ) -> Optional["Link"]: """ Convert an pypi json document from a simple repository page into a Link. """ file_url = file_data.get("url") if file_url is None: return None url = _ensure_quoted_url(urllib.parse.urljoin(page_url, file_url)) pyrequire = file_data.get("requires-python") yanked_reason = file_data.get("yanked") dist_info_metadata = file_data.get("dist-info-metadata") hashes = file_data.get("hashes", {}) # The Link.yanked_reason expects an empty string instead of a boolean. if yanked_reason and not isinstance(yanked_reason, str): yanked_reason = "" # The Link.yanked_reason expects None instead of False. elif not yanked_reason: yanked_reason = None return cls( url, comes_from=page_url, requires_python=pyrequire, yanked_reason=yanked_reason, hashes=hashes, dist_info_metadata=dist_info_metadata, ) @classmethod def from_element( cls, anchor_attribs: Dict[str, Optional[str]], page_url: str, base_url: str, ) -> Optional["Link"]: """ Convert an anchor element's attributes in a simple repository page to a Link. """ href = anchor_attribs.get("href") if not href: return None url = _ensure_quoted_url(urllib.parse.urljoin(base_url, href)) pyrequire = anchor_attribs.get("data-requires-python") yanked_reason = anchor_attribs.get("data-yanked") dist_info_metadata = anchor_attribs.get("data-dist-info-metadata") return cls( url, comes_from=page_url, requires_python=pyrequire, yanked_reason=yanked_reason, dist_info_metadata=dist_info_metadata, ) def __str__(self) -> str: if self.requires_python: rp = f" (requires-python:{self.requires_python})" else: rp = "" if self.comes_from: return "{} (from {}){}".format( redact_auth_from_url(self._url), self.comes_from, rp ) else: return redact_auth_from_url(str(self._url)) def __repr__(self) -> str: return f"<Link {self}>" @property def url(self) -> str: return self._url @property def filename(self) -> str: path = self.path.rstrip("/") name = posixpath.basename(path) if not name: # Make sure we don't leak auth information if the netloc # includes a username and password. netloc, user_pass = split_auth_from_netloc(self.netloc) return netloc name = urllib.parse.unquote(name) assert name, f"URL {self._url!r} produced no filename" return name @property def file_path(self) -> str: return url_to_path(self.url) @property def scheme(self) -> str: return self._parsed_url.scheme @property def netloc(self) -> str: """ This can contain auth information. """ return self._parsed_url.netloc @property def path(self) -> str: return urllib.parse.unquote(self._parsed_url.path) def splitext(self) -> Tuple[str, str]: return splitext(posixpath.basename(self.path.rstrip("/"))) @property def ext(self) -> str: return self.splitext()[1] @property def url_without_fragment(self) -> str: scheme, netloc, path, query, fragment = self._parsed_url return urllib.parse.urlunsplit((scheme, netloc, path, query, "")) _egg_fragment_re = re.compile(r"[#&]egg=([^&]*)") # Per PEP 508. _project_name_re = re.compile( r"^([A-Z0-9]|[A-Z0-9][A-Z0-9._-]*[A-Z0-9])$", re.IGNORECASE ) def _egg_fragment(self) -> Optional[str]: match = self._egg_fragment_re.search(self._url) if not match: return None # An egg fragment looks like a PEP 508 project name, along with # an optional extras specifier. Anything else is invalid. project_name = match.group(1) if not self._project_name_re.match(project_name): deprecated( reason=f"{self} contains an egg fragment with a non-PEP 508 name", replacement="to use the req @ url syntax, and remove the egg fragment", gone_in="25.0", issue=11617, ) return project_name _subdirectory_fragment_re = re.compile(r"[#&]subdirectory=([^&]*)") @property def subdirectory_fragment(self) -> Optional[str]: match = self._subdirectory_fragment_re.search(self._url) if not match: return None return match.group(1) def metadata_link(self) -> Optional["Link"]: """Implementation of PEP 658 parsing.""" # Note that Link.from_element() parsing the "data-dist-info-metadata" attribute # from an HTML anchor tag is typically how the Link.dist_info_metadata attribute # gets set. if self.dist_info_metadata is None: return None metadata_url = f"{self.url_without_fragment}.metadata" # If data-dist-info-metadata="true" is set, then the metadata file exists, # but there is no information about its checksum or anything else. if self.dist_info_metadata != "true": link_hash = LinkHash.split_hash_name_and_value(self.dist_info_metadata) else: link_hash = None if link_hash is None: return Link(metadata_url) return Link(metadata_url, hashes=link_hash.as_dict()) def as_hashes(self) -> Hashes: return Hashes({k: [v] for k, v in self._hashes.items()}) @property def hash(self) -> Optional[str]: return next(iter(self._hashes.values()), None) @property def hash_name(self) -> Optional[str]: return next(iter(self._hashes), None) @property def show_url(self) -> str: return posixpath.basename(self._url.split("#", 1)[0].split("?", 1)[0]) @property def is_file(self) -> bool: return self.scheme == "file" def is_existing_dir(self) -> bool: return self.is_file and os.path.isdir(self.file_path) @property def is_wheel(self) -> bool: return self.ext == WHEEL_EXTENSION @property def is_vcs(self) -> bool: from pip._internal.vcs import vcs return self.scheme in vcs.all_schemes @property def is_yanked(self) -> bool: return self.yanked_reason is not None @property def has_hash(self) -> bool: return bool(self._hashes) def is_hash_allowed(self, hashes: Optional[Hashes]) -> bool: """ Return True if the link has a hash and it is allowed by `hashes`. """ if hashes is None: return False return any(hashes.is_hash_allowed(k, v) for k, v in self._hashes.items()) class _CleanResult(NamedTuple): """Convert link for equivalency check. This is used in the resolver to check whether two URL-specified requirements likely point to the same distribution and can be considered equivalent. This equivalency logic avoids comparing URLs literally, which can be too strict (e.g. "a=1&b=2" vs "b=2&a=1") and produce conflicts unexpecting to users. Currently this does three things: 1. Drop the basic auth part. This is technically wrong since a server can serve different content based on auth, but if it does that, it is even impossible to guarantee two URLs without auth are equivalent, since the user can input different auth information when prompted. So the practical solution is to assume the auth doesn't affect the response. 2. Parse the query to avoid the ordering issue. Note that ordering under the same key in the query are NOT cleaned; i.e. "a=1&a=2" and "a=2&a=1" are still considered different. 3. Explicitly drop most of the fragment part, except ``subdirectory=`` and hash values, since it should have no impact the downloaded content. Note that this drops the "egg=" part historically used to denote the requested project (and extras), which is wrong in the strictest sense, but too many people are supplying it inconsistently to cause superfluous resolution conflicts, so we choose to also ignore them. """ parsed: urllib.parse.SplitResult query: Dict[str, List[str]] subdirectory: str hashes: Dict[str, str] def _clean_link(link: Link) -> _CleanResult: parsed = link._parsed_url netloc = parsed.netloc.rsplit("@", 1)[-1] # According to RFC 8089, an empty host in file: means localhost. if parsed.scheme == "file" and not netloc: netloc = "localhost" fragment = urllib.parse.parse_qs(parsed.fragment) if "egg" in fragment: logger.debug("Ignoring egg= fragment in %s", link) try: # If there are multiple subdirectory values, use the first one. # This matches the behavior of Link.subdirectory_fragment. subdirectory = fragment["subdirectory"][0] except (IndexError, KeyError): subdirectory = "" # If there are multiple hash values under the same algorithm, use the # first one. This matches the behavior of Link.hash_value. hashes = {k: fragment[k][0] for k in _SUPPORTED_HASHES if k in fragment} return _CleanResult( parsed=parsed._replace(netloc=netloc, query="", fragment=""), query=urllib.parse.parse_qs(parsed.query), subdirectory=subdirectory, hashes=hashes, ) @functools.lru_cache(maxsize=None) def links_equivalent(link1: Link, link2: Link) -> bool: return _clean_link(link1) == _clean_link(link2)