distlib.locators

distlib.locators

Source code for distlib.locators

# -*- coding: utf-8 -*-
#
# Copyright (C) 2012-2015 Vinay Sajip.
# Licensed to the Python Software Foundation under a contributor agreement.
# See LICENSE.txt and CONTRIBUTORS.txt.
#

import gzip
from io import BytesIO
import json
import logging
import os
import posixpath
import re
try:
    import threading
except ImportError:  # pragma: no cover
    import dummy_threading as threading
import zlib

from . import DistlibException
from .compat import (urljoin, urlparse, urlunparse, url2pathname, pathname2url,
                     queue, quote, unescape, build_opener,
                     HTTPRedirectHandler as BaseRedirectHandler, text_type,
                     Request, HTTPError, URLError)
from .database import Distribution, DistributionPath, make_dist
from .metadata import Metadata, MetadataInvalidError
from .util import (cached_property, ensure_slash, split_filename, get_project_data,
                   parse_requirement, parse_name_and_version, ServerProxy,
                   normalize_name)
from .version import get_scheme, UnsupportedVersionError
from .wheel import Wheel, is_compatible

logger = logging.getLogger(__name__)

HASHER_HASH = re.compile(r'^(\w+)=([a-f0-9]+)')
CHARSET = re.compile(r';\s*charset\s*=\s*(.*)\s*$', re.I)
HTML_CONTENT_TYPE = re.compile('text/html|application/x(ht)?ml')
DEFAULT_INDEX = 'https://pypi.org/pypi'

[docs]def get_all_distribution_names(url=None): """ Return all distribution names known by an index. :param url: The URL of the index. :return: A list of all known distribution names. """ if url is None: url = DEFAULT_INDEX client = ServerProxy(url, timeout=3.0) try: return client.list_packages() finally: client('close')()
class RedirectHandler(BaseRedirectHandler): """ A class to work around a bug in some Python 3.2.x releases. """ # There's a bug in the base version for some 3.2.x # (e.g. 3.2.2 on Ubuntu Oneiric). If a Location header # returns e.g. /abc, it bails because it says the scheme '' # is bogus, when actually it should use the request's # URL for the scheme. See Python issue #13696. def http_error_302(self, req, fp, code, msg, headers): # Some servers (incorrectly) return multiple Location headers # (so probably same goes for URI). Use first header. newurl = None for key in ('location', 'uri'): if key in headers: newurl = headers[key] break if newurl is None: # pragma: no cover return urlparts = urlparse(newurl) if urlparts.scheme == '': newurl = urljoin(req.get_full_url(), newurl) if hasattr(headers, 'replace_header'): headers.replace_header(key, newurl) else: headers[key] = newurl return BaseRedirectHandler.http_error_302(self, req, fp, code, msg, headers) http_error_301 = http_error_303 = http_error_307 = http_error_302
[docs]class Locator(object): """ A base class for locators - things that locate distributions. """ source_extensions = ('.tar.gz', '.tar.bz2', '.tar', '.zip', '.tgz', '.tbz') binary_extensions = ('.egg', '.exe', '.whl') excluded_extensions = ('.pdf',) # A list of tags indicating which wheels you want to match. The default # value of None matches against the tags compatible with the running # Python. If you want to match other values, set wheel_tags on a locator # instance to a list of tuples (pyver, abi, arch) which you want to match. wheel_tags = None downloadable_extensions = source_extensions + ('.whl',)
[docs] def __init__(self, scheme='default'): """ Initialise an instance. :param scheme: Because locators look for most recent versions, they need to know the version scheme to use. This specifies the current PEP-recommended scheme - use ``'legacy'`` if you need to support existing distributions on PyPI. """ self._cache = {} self.scheme = scheme # Because of bugs in some of the handlers on some of the platforms, # we use our own opener rather than just using urlopen. self.opener = build_opener(RedirectHandler()) # If get_project() is called from locate(), the matcher instance # is set from the requirement passed to locate(). See issue #18 for # why this can be useful to know. self.matcher = None self.errors = queue.Queue()
[docs] def get_errors(self): """ Return any errors which have occurred. """ result = [] while not self.errors.empty(): # pragma: no cover try: e = self.errors.get(False) result.append(e) except self.errors.Empty: continue self.errors.task_done() return result
def clear_errors(self): """ Clear any errors which may have been logged. """ # Just get the errors and throw them away self.get_errors() def clear_cache(self): self._cache.clear() def _get_scheme(self): return self._scheme def _set_scheme(self, value): self._scheme = value scheme = property(_get_scheme, _set_scheme) def _get_project(self, name): """ For a given project, get a dictionary mapping available versions to Distribution instances. This should be implemented in subclasses. If called from a locate() request, self.matcher will be set to a matcher for the requirement to satisfy, otherwise it will be None. """ raise NotImplementedError('Please implement in the subclass')
[docs] def get_distribution_names(self): """ Return all the distribution names known to this locator. """ raise NotImplementedError('Please implement in the subclass')
[docs] def get_project(self, name): """ For a given project, get a dictionary mapping available versions to Distribution instances. This calls _get_project to do all the work, and just implements a caching layer on top. """ if self._cache is None: # pragma: no cover result = self._get_project(name) elif name in self._cache: result = self._cache[name] else: self.clear_errors() result = self._get_project(name) self._cache[name] = result return result
def score_url(self, url): """ Give an url a score which can be used to choose preferred URLs for a given project release. """ t = urlparse(url) basename = posixpath.basename(t.path) compatible = True is_wheel = basename.endswith('.whl') is_downloadable = basename.endswith(self.downloadable_extensions) if is_wheel: compatible = is_compatible(Wheel(basename), self.wheel_tags) return (t.scheme == 'https', 'pypi.org' in t.netloc, is_downloadable, is_wheel, compatible, basename) def prefer_url(self, url1, url2): """ Choose one of two URLs where both are candidates for distribution archives for the same version of a distribution (for example, .tar.gz vs. zip). The current implementation favours https:// URLs over http://, archives from PyPI over those from other locations, wheel compatibility (if a wheel) and then the archive name. """ result = url2 if url1: s1 = self.score_url(url1) s2 = self.score_url(url2) if s1 > s2: result = url1 if result != url2: logger.debug('Not replacing %r with %r', url1, url2) else: logger.debug('Replacing %r with %r', url1, url2) return result def split_filename(self, filename, project_name): """ Attempt to split a filename in project name, version and Python version. """ return split_filename(filename, project_name)
[docs] def convert_url_to_download_info(self, url, project_name): """ See if a URL is a candidate for a download URL for a project (the URL has typically been scraped from an HTML page). If it is, a dictionary is returned with keys "name", "version", "filename" and "url"; otherwise, None is returned. """ def same_project(name1, name2): return normalize_name(name1) == normalize_name(name2) result = None scheme, netloc, path, params, query, frag = urlparse(url) if frag.lower().startswith('egg='): # pragma: no cover logger.debug('%s: version hint in fragment: %r', project_name, frag) m = HASHER_HASH.match(frag) if m: algo, digest = m.groups() else: algo, digest = None, None origpath = path if path and path[-1] == '/': # pragma: no cover path = path[:-1] if path.endswith('.whl'): try: wheel = Wheel(path) if not is_compatible(wheel, self.wheel_tags): logger.debug('Wheel not compatible: %s', path) else: if project_name is None: include = True else: include = same_project(wheel.name, project_name) if include: result = { 'name': wheel.name, 'version': wheel.version, 'filename': wheel.filename, 'url': urlunparse((scheme, netloc, origpath, params, query, '')), 'python-version': ', '.join( ['.'.join(list(v[2:])) for v in wheel.pyver]), } except Exception as e: # pragma: no cover logger.warning('invalid path for wheel: %s', path) elif not path.endswith(self.downloadable_extensions): # pragma: no cover logger.debug('Not downloadable: %s', path) else: # downloadable extension path = filename = posixpath.basename(path) for ext in self.downloadable_extensions: if path.endswith(ext): path = path[:-len(ext)] t = self.split_filename(path, project_name) if not t: # pragma: no cover logger.debug('No match for project/version: %s', path) else: name, version, pyver = t if not project_name or same_project(project_name, name): result = { 'name': name, 'version': version, 'filename': filename, 'url': urlunparse((scheme, netloc, origpath, params, query, '')), #'packagetype': 'sdist', } if pyver: # pragma: no cover result['python-version'] = pyver break if result and algo: result['%s_digest' % algo] = digest return result
def _get_digest(self, info): """ Get a digest from a dictionary by looking at a "digests" dictionary or keys of the form 'algo_digest'. Returns a 2-tuple (algo, digest) if found, else None. Currently looks only for SHA256, then MD5. """ result = None if 'digests' in info: digests = info['digests'] for algo in ('sha256', 'md5'): if algo in digests: result = (algo, digests[algo]) break if not result: for algo in ('sha256', 'md5'): key = '%s_digest' % algo if key in info: result = (algo, info[key]) break return result def _update_version_data(self, result, info): """ Update a result dictionary (the final result from _get_project) with a dictionary for a specific version, which typically holds information gleaned from a filename or URL for an archive for the distribution. """ name = info.pop('name') version = info.pop('version') if version in result: dist = result[version] md = dist.metadata else: dist = make_dist(name, version, scheme=self.scheme) md = dist.metadata dist.digest = digest = self._get_digest(info) url = info['url'] result['digests'][url] = digest if md.source_url != info['url']: md.source_url = self.prefer_url(md.source_url, url) result['urls'].setdefault(version, set()).add(url) dist.locator = self result[version] = dist
[docs] def locate(self, requirement, prereleases=False): """ Find the most recent distribution which matches the given requirement. :param requirement: A requirement of the form 'foo (1.0)' or perhaps 'foo (>= 1.0, < 2.0, != 1.3)' :param prereleases: If ``True``, allow pre-release versions to be located. Otherwise, pre-release versions are not returned. :return: A :class:`Distribution` instance, or ``None`` if no such distribution could be located. """ result = None r = parse_requirement(requirement) if r is None: # pragma: no cover raise DistlibException('Not a valid requirement: %r' % requirement) scheme = get_scheme(self.scheme) self.matcher = matcher = scheme.matcher(r.requirement) logger.debug('matcher: %s (%s)', matcher, type(matcher).__name__) versions = self.get_project(r.name) if len(versions) > 2: # urls and digests keys are present # sometimes, versions are invalid slist = [] vcls = matcher.version_class for k in versions: if k in ('urls', 'digests'): continue try: if not matcher.match(k): pass # logger.debug('%s did not match %r', matcher, k) else: if prereleases or not vcls(k).is_prerelease: slist.append(k) # else: # logger.debug('skipping pre-release ' # 'version %s of %s', k, matcher.name) except Exception: # pragma: no cover logger.warning('error matching %s with %r', matcher, k) pass # slist.append(k) if len(slist) > 1: slist = sorted(slist, key=scheme.key) if slist: logger.debug('sorted list: %s', slist) version = slist[-1] result = versions[version] if result: if r.extras: result.extras = r.extras result.download_urls = versions.get('urls', {}).get(version, set()) d = {} sd = versions.get('digests', {}) for url in result.download_urls: if url in sd: # pragma: no cover d[url] = sd[url] result.digests = d self.matcher = None return result
[docs]class PyPIRPCLocator(Locator): """ This locator uses XML-RPC to locate distributions. It therefore cannot be used with simple mirrors (that only mirror file content). """
[docs] def __init__(self, url, **kwargs): """ Initialise an instance. :param url: The URL to use for XML-RPC. :param kwargs: Passed to the superclass constructor. """ super(PyPIRPCLocator, self).__init__(**kwargs) self.base_url = url self.client = ServerProxy(url, timeout=3.0)
def get_distribution_names(self): """ Return all the distribution names known to this locator. """ return set(self.client.list_packages()) def _get_project(self, name): result = {'urls': {}, 'digests': {}} versions = self.client.package_releases(name, True) for v in versions: urls = self.client.release_urls(name, v) data = self.client.release_data(name, v) metadata = Metadata(scheme=self.scheme) metadata.name = data['name'] metadata.version = data['version'] metadata.license = data.get('license') metadata.keywords = data.get('keywords', []) metadata.summary = data.get('summary') dist = Distribution(metadata) if urls: info = urls[0] metadata.source_url = info['url'] dist.digest = self._get_digest(info) dist.locator = self result[v] = dist for info in urls: url = info['url'] digest = self._get_digest(info) result['urls'].setdefault(v, set()).add(url) result['digests'][url] = digest return result
[docs]class PyPIJSONLocator(Locator): """ This locator uses PyPI's JSON interface. It's very limited in functionality and probably not worth using. """
[docs] def __init__(self, url, **kwargs): super(PyPIJSONLocator, self).__init__(**kwargs) self.base_url = ensure_slash(url)
def get_distribution_names(self): """ Return all the distribution names known to this locator. """ raise NotImplementedError('Not available from this locator') def _get_project(self, name): result = {'urls': {}, 'digests': {}} url = urljoin(self.base_url, '%s/json' % quote(name)) try: resp = self.opener.open(url) data = resp.read().decode() # for now d = json.loads(data) md = Metadata(scheme=self.scheme) data = d['info'] md.name = data['name'] md.version = data['version'] md.license = data.get('license') md.keywords = data.get('keywords', []) md.summary = data.get('summary') dist = Distribution(md) dist.locator = self urls = d['urls'] result[md.version] = dist for info in d['urls']: url = info['url'] dist.download_urls.add(url) dist.digests[url] = self._get_digest(info) result['urls'].setdefault(md.version, set()).add(url) result['digests'][url] = self._get_digest(info) # Now get other releases for version, infos in d['releases'].items(): if version == md.version: continue # already done omd = Metadata(scheme=self.scheme) omd.name = md.name omd.version = version odist = Distribution(omd) odist.locator = self result[version] = odist for info in infos: url = info['url'] odist.download_urls.add(url) odist.digests[url] = self._get_digest(info) result['urls'].setdefault(version, set()).add(url) result['digests'][url] = self._get_digest(info) # for info in urls: # md.source_url = info['url'] # dist.digest = self._get_digest(info) # dist.locator = self # for info in urls: # url = info['url'] # result['urls'].setdefault(md.version, set()).add(url) # result['digests'][url] = self._get_digest(info) except Exception as e: self.errors.put(text_type(e)) logger.exception('JSON fetch failed: %s', e) return result
class Page(object): """ This class represents a scraped HTML page. """ # The following slightly hairy-looking regex just looks for the contents of # an anchor link, which has an attribute "href" either immediately preceded # or immediately followed by a "rel" attribute. The attribute values can be # declared with double quotes, single quotes or no quotes - which leads to # the length of the expression. _href = re.compile(""" (rel\\s*=\\s*(?:"(?P<rel1>[^"]*)"|'(?P<rel2>[^']*)'|(?P<rel3>[^>\\s\n]*))\\s+)? href\\s*=\\s*(?:"(?P<url1>[^"]*)"|'(?P<url2>[^']*)'|(?P<url3>[^>\\s\n]*)) (\\s+rel\\s*=\\s*(?:"(?P<rel4>[^"]*)"|'(?P<rel5>[^']*)'|(?P<rel6>[^>\\s\n]*)))? """, re.I | re.S | re.X) _base = re.compile(r"""<base\s+href\s*=\s*['"]?([^'">]+)""", re.I | re.S) def __init__(self, data, url): """ Initialise an instance with the Unicode page contents and the URL they came from. """ self.data = data self.base_url = self.url = url m = self._base.search(self.data) if m: self.base_url = m.group(1) _clean_re = re.compile(r'[^a-z0-9$&+,/:;=?@.#%_\\|-]', re.I) @cached_property def links(self): """ Return the URLs of all the links on a page together with information about their "rel" attribute, for determining which ones to treat as downloads and which ones to queue for further scraping. """ def clean(url): "Tidy up an URL." scheme, netloc, path, params, query, frag = urlparse(url) return urlunparse((scheme, netloc, quote(path), params, query, frag)) result = set() for match in self._href.finditer(self.data): d = match.groupdict('') rel = (d['rel1'] or d['rel2'] or d['rel3'] or d['rel4'] or d['rel5'] or d['rel6']) url = d['url1'] or d['url2'] or d['url3'] url = urljoin(self.base_url, url) url = unescape(url) url = self._clean_re.sub(lambda m: '%%%2x' % ord(m.group(0)), url) result.add((url, rel)) # We sort the result, hoping to bring the most recent versions # to the front result = sorted(result, key=lambda t: t[0], reverse=True) return result
[docs]class SimpleScrapingLocator(Locator): """ A locator which scrapes HTML pages to locate downloads for a distribution. This runs multiple threads to do the I/O; performance is at least as good as pip's PackageFinder, which works in an analogous fashion. """ # These are used to deal with various Content-Encoding schemes. decoders = { 'deflate': zlib.decompress, 'gzip': lambda b: gzip.GzipFile(fileobj=BytesIO(b)).read(), 'none': lambda b: b, }
[docs] def __init__(self, url, timeout=None, num_workers=10, **kwargs): """ Initialise an instance. :param url: The root URL to use for scraping. :param timeout: The timeout, in seconds, to be applied to requests. This defaults to ``None`` (no timeout specified). :param num_workers: The number of worker threads you want to do I/O, This defaults to 10. :param kwargs: Passed to the superclass. """ super(SimpleScrapingLocator, self).__init__(**kwargs) self.base_url = ensure_slash(url) self.timeout = timeout self._page_cache = {} self._seen = set() self._to_fetch = queue.Queue() self._bad_hosts = set() self.skip_externals = False self.num_workers = num_workers self._lock = threading.RLock() # See issue #45: we need to be resilient when the locator is used # in a thread, e.g. with concurrent.futures. We can't use self._lock # as it is for coordinating our internal threads - the ones created # in _prepare_threads. self._gplock = threading.RLock() self.platform_check = False # See issue #112
def _prepare_threads(self): """ Threads are created only when get_project is called, and terminate before it returns. They are there primarily to parallelise I/O (i.e. fetching web pages). """ self._threads = [] for i in range(self.num_workers): t = threading.Thread(target=self._fetch) t.daemon = True t.start() self._threads.append(t) def _wait_threads(self): """ Tell all the threads to terminate (by sending a sentinel value) and wait for them to do so. """ # Note that you need two loops, since you can't say which # thread will get each sentinel for t in self._threads: self._to_fetch.put(None) # sentinel for t in self._threads: t.join() self._threads = [] def _get_project(self, name): result = {'urls': {}, 'digests': {}} with self._gplock: self.result = result self.project_name = name url = urljoin(self.base_url, '%s/' % quote(name)) self._seen.clear() self._page_cache.clear() self._prepare_threads() try: logger.debug('Queueing %s', url) self._to_fetch.put(url) self._to_fetch.join() finally: self._wait_threads() del self.result return result platform_dependent = re.compile(r'\b(linux_(i\d86|x86_64|arm\w+)|' r'win(32|_amd64)|macosx_?\d+)\b', re.I) def _is_platform_dependent(self, url): """ Does an URL refer to a platform-specific download? """ return self.platform_dependent.search(url) def _process_download(self, url): """ See if an URL is a suitable download for a project. If it is, register information in the result dictionary (for _get_project) about the specific version it's for. Note that the return value isn't actually used other than as a boolean value. """ if self.platform_check and self._is_platform_dependent(url): info = None else: info = self.convert_url_to_download_info(url, self.project_name) logger.debug('process_download: %s -> %s', url, info) if info: with self._lock: # needed because self.result is shared self._update_version_data(self.result, info) return info def _should_queue(self, link, referrer, rel): """ Determine whether a link URL from a referring page and with a particular "rel" attribute should be queued for scraping. """ scheme, netloc, path, _, _, _ = urlparse(link) if path.endswith(self.source_extensions + self.binary_extensions + self.excluded_extensions): result = False elif self.skip_externals and not link.startswith(self.base_url): result = False elif not referrer.startswith(self.base_url): result = False elif rel not in ('homepage', 'download'): result = False elif scheme not in ('http', 'https', 'ftp'): result = False elif self._is_platform_dependent(link): result = False else: host = netloc.split(':', 1)[0] if host.lower() == 'localhost': result = False else: result = True logger.debug('should_queue: %s (%s) from %s -> %s', link, rel, referrer, result) return result def _fetch(self): """ Get a URL to fetch from the work queue, get the HTML page, examine its links for download candidates and candidates for further scraping. This is a handy method to run in a thread. """ while True: url = self._to_fetch.get() try: if url: page = self.get_page(url) if page is None: # e.g. after an error continue for link, rel in page.links: if link not in self._seen: try: self._seen.add(link) if (not self._process_download(link) and self._should_queue(link, url, rel)): logger.debug('Queueing %s from %s', link, url) self._to_fetch.put(link) except MetadataInvalidError: # e.g. invalid versions pass except Exception as e: # pragma: no cover self.errors.put(text_type(e)) finally: # always do this, to avoid hangs :-) self._to_fetch.task_done() if not url: #logger.debug('Sentinel seen, quitting.') break def get_page(self, url): """ Get the HTML for an URL, possibly from an in-memory cache. XXX TODO Note: this cache is never actually cleared. It's assumed that the data won't get stale over the lifetime of a locator instance (not necessarily true for the default_locator). """ # http://peak.telecommunity.com/DevCenter/EasyInstall#package-index-api scheme, netloc, path, _, _, _ = urlparse(url) if scheme == 'file' and os.path.isdir(url2pathname(path)): url = urljoin(ensure_slash(url), 'index.html') if url in self._page_cache: result = self._page_cache[url] logger.debug('Returning %s from cache: %s', url, result) else: host = netloc.split(':', 1)[0] result = None if host in self._bad_hosts: logger.debug('Skipping %s due to bad host %s', url, host) else: req = Request(url, headers={'Accept-encoding': 'identity'}) try: logger.debug('Fetching %s', url) resp = self.opener.open(req, timeout=self.timeout) logger.debug('Fetched %s', url) headers = resp.info() content_type = headers.get('Content-Type', '') if HTML_CONTENT_TYPE.match(content_type): final_url = resp.geturl() data = resp.read() encoding = headers.get('Content-Encoding') if encoding: decoder = self.decoders[encoding] # fail if not found data = decoder(data) encoding = 'utf-8' m = CHARSET.search(content_type) if m: encoding = m.group(1) try: data = data.decode(encoding) except UnicodeError: # pragma: no cover data = data.decode('latin-1') # fallback result = Page(data, final_url) self._page_cache[final_url] = result except HTTPError as e: if e.code != 404: logger.exception('Fetch failed: %s: %s', url, e) except URLError as e: # pragma: no cover logger.exception('Fetch failed: %s: %s', url, e) with self._lock: self._bad_hosts.add(host) except Exception as e: # pragma: no cover logger.exception('Fetch failed: %s: %s', url, e) finally: self._page_cache[url] = result # even if None (failure) return result _distname_re = re.compile('<a href=[^>]*>([^<]+)<') def get_distribution_names(self): """ Return all the distribution names known to this locator. """ result = set() page = self.get_page(self.base_url) if not page: raise DistlibException('Unable to get %s' % self.base_url) for match in self._distname_re.finditer(page.data): result.add(match.group(1)) return result
[docs]class DirectoryLocator(Locator): """ This class locates distributions in a directory tree. """
[docs] def __init__(self, path, **kwargs): """ Initialise an instance. :param path: The root of the directory tree to search. :param kwargs: Passed to the superclass constructor, except for: * recursive - if True (the default), subdirectories are recursed into. If False, only the top-level directory is searched, """ self.recursive = kwargs.pop('recursive', True) super(DirectoryLocator, self).__init__(**kwargs) path = os.path.abspath(path) if not os.path.isdir(path): # pragma: no cover raise DistlibException('Not a directory: %r' % path) self.base_dir = path
def should_include(self, filename, parent): """ Should a filename be considered as a candidate for a distribution archive? As well as the filename, the directory which contains it is provided, though not used by the current implementation. """ return filename.endswith(self.downloadable_extensions) def _get_project(self, name): result = {'urls': {}, 'digests': {}} for root, dirs, files in os.walk(self.base_dir): for fn in files: if self.should_include(fn, root): fn = os.path.join(root, fn) url = urlunparse(('file', '', pathname2url(os.path.abspath(fn)), '', '', '')) info = self.convert_url_to_download_info(url, name) if info: self._update_version_data(result, info) if not self.recursive: break return result def get_distribution_names(self): """ Return all the distribution names known to this locator. """ result = set() for root, dirs, files in os.walk(self.base_dir): for fn in files: if self.should_include(fn, root): fn = os.path.join(root, fn) url = urlunparse(('file', '', pathname2url(os.path.abspath(fn)), '', '', '')) info = self.convert_url_to_download_info(url, None) if info: result.add(info['name']) if not self.recursive: break return result
class JSONLocator(Locator): """ This locator uses special extended metadata (not available on PyPI) and is the basis of performant dependency resolution in distlib. Other locators require archive downloads before dependencies can be determined! As you might imagine, that can be slow. """ def get_distribution_names(self): """ Return all the distribution names known to this locator. """ raise NotImplementedError('Not available from this locator') def _get_project(self, name): result = {'urls': {}, 'digests': {}} data = get_project_data(name) if data: for info in data.get('files', []): if info['ptype'] != 'sdist' or info['pyversion'] != 'source': continue # We don't store summary in project metadata as it makes # the data bigger for no benefit during dependency # resolution dist = make_dist(data['name'], info['version'], summary=data.get('summary', 'Placeholder for summary'), scheme=self.scheme) md = dist.metadata md.source_url = info['url'] # TODO SHA256 digest if 'digest' in info and info['digest']: dist.digest = ('md5', info['digest']) md.dependencies = info.get('requirements', {}) dist.exports = info.get('exports', {}) result[dist.version] = dist result['urls'].setdefault(dist.version, set()).add(info['url']) return result
[docs]class DistPathLocator(Locator): """ This locator finds installed distributions in a path. It can be useful for adding to an :class:`AggregatingLocator`. """
[docs] def __init__(self, distpath, **kwargs): """ Initialise an instance. :param distpath: A :class:`DistributionPath` instance to search. """ super(DistPathLocator, self).__init__(**kwargs) assert isinstance(distpath, DistributionPath) self.distpath = distpath
def _get_project(self, name): dist = self.distpath.get_distribution(name) if dist is None: result = {'urls': {}, 'digests': {}} else: result = { dist.version: dist, 'urls': {dist.version: set([dist.source_url])}, 'digests': {dist.version: set([None])} } return result
[docs]class AggregatingLocator(Locator): """ This class allows you to chain and/or merge a list of locators. """
[docs] def __init__(self, *locators, **kwargs): """ Initialise an instance. :param locators: The list of locators to search. :param kwargs: Passed to the superclass constructor, except for: * merge - if False (the default), the first successful search from any of the locators is returned. If True, the results from all locators are merged (this can be slow). """ self.merge = kwargs.pop('merge', False) self.locators = locators super(AggregatingLocator, self).__init__(**kwargs)
def clear_cache(self): super(AggregatingLocator, self).clear_cache() for locator in self.locators: locator.clear_cache() def _set_scheme(self, value): self._scheme = value for locator in self.locators: locator.scheme = value scheme = property(Locator.scheme.fget, _set_scheme) def _get_project(self, name): result = {} for locator in self.locators: d = locator.get_project(name) if d: if self.merge: files = result.get('urls', {}) digests = result.get('digests', {}) # next line could overwrite result['urls'], result['digests'] result.update(d) df = result.get('urls') if files and df: for k, v in files.items(): if k in df: df[k] |= v else: df[k] = v dd = result.get('digests') if digests and dd: dd.update(digests) else: # See issue #18. If any dists are found and we're looking # for specific constraints, we only return something if # a match is found. For example, if a DirectoryLocator # returns just foo (1.0) while we're looking for # foo (>= 2.0), we'll pretend there was nothing there so # that subsequent locators can be queried. Otherwise we # would just return foo (1.0) which would then lead to a # failure to find foo (>= 2.0), because other locators # weren't searched. Note that this only matters when # merge=False. if self.matcher is None: found = True else: found = False for k in d: if self.matcher.match(k): found = True break if found: result = d break return result def get_distribution_names(self): """ Return all the distribution names known to this locator. """ result = set() for locator in self.locators: try: result |= locator.get_distribution_names() except NotImplementedError: pass return result
# We use a legacy scheme simply because most of the dists on PyPI use legacy # versions which don't conform to PEP 440. default_locator = AggregatingLocator( # JSONLocator(), # don't use as PEP 426 is withdrawn SimpleScrapingLocator('https://pypi.org/simple/', timeout=3.0), scheme='legacy') locate = default_locator.locate
[docs]class DependencyFinder(object): """ Locate dependencies for distributions. """
[docs] def __init__(self, locator=None): """ Initialise an instance, using the specified locator to locate distributions. """ self.locator = locator or default_locator self.scheme = get_scheme(self.locator.scheme)
def add_distribution(self, dist): """ Add a distribution to the finder. This will update internal information about who provides what. :param dist: The distribution to add. """ logger.debug('adding distribution %s', dist) name = dist.key self.dists_by_name[name] = dist self.dists[(name, dist.version)] = dist for p in dist.provides: name, version = parse_name_and_version(p) logger.debug('Add to provided: %s, %s, %s', name, version, dist) self.provided.setdefault(name, set()).add((version, dist)) def remove_distribution(self, dist): """ Remove a distribution from the finder. This will update internal information about who provides what. :param dist: The distribution to remove. """ logger.debug('removing distribution %s', dist) name = dist.key del self.dists_by_name[name] del self.dists[(name, dist.version)] for p in dist.provides: name, version = parse_name_and_version(p) logger.debug('Remove from provided: %s, %s, %s', name, version, dist) s = self.provided[name] s.remove((version, dist)) if not s: del self.provided[name] def get_matcher(self, reqt): """ Get a version matcher for a requirement. :param reqt: The requirement :type reqt: str :return: A version matcher (an instance of :class:`distlib.version.Matcher`). """ try: matcher = self.scheme.matcher(reqt) except UnsupportedVersionError: # pragma: no cover # XXX compat-mode if cannot read the version name = reqt.split()[0] matcher = self.scheme.matcher(name) return matcher def find_providers(self, reqt): """ Find the distributions which can fulfill a requirement. :param reqt: The requirement. :type reqt: str :return: A set of distribution which can fulfill the requirement. """ matcher = self.get_matcher(reqt) name = matcher.key # case-insensitive result = set() provided = self.provided if name in provided: for version, provider in provided[name]: try: match = matcher.match(version) except UnsupportedVersionError: match = False if match: result.add(provider) break return result def try_to_replace(self, provider, other, problems): """ Attempt to replace one provider with another. This is typically used when resolving dependencies from multiple sources, e.g. A requires (B >= 1.0) while C requires (B >= 1.1). For successful replacement, ``provider`` must meet all the requirements which ``other`` fulfills. :param provider: The provider we are trying to replace with. :param other: The provider we're trying to replace. :param problems: If False is returned, this will contain what problems prevented replacement. This is currently a tuple of the literal string 'cantreplace', ``provider``, ``other`` and the set of requirements that ``provider`` couldn't fulfill. :return: True if we can replace ``other`` with ``provider``, else False. """ rlist = self.reqts[other] unmatched = set() for s in rlist: matcher = self.get_matcher(s) if not matcher.match(provider.version): unmatched.add(s) if unmatched: # can't replace other with provider problems.add(('cantreplace', provider, other, frozenset(unmatched))) result = False else: # can replace other with provider self.remove_distribution(other) del self.reqts[other] for s in rlist: self.reqts.setdefault(provider, set()).add(s) self.add_distribution(provider) result = True return result
[docs] def find(self, requirement, meta_extras=None, prereleases=False): """ Find a distribution and all distributions it depends on. :param requirement: The requirement specifying the distribution to find, or a Distribution instance. :param meta_extras: A list of meta extras such as :test:, :build: and so on. :param prereleases: If ``True``, allow pre-release versions to be returned - otherwise, don't return prereleases unless they're all that's available. Return a set of :class:`Distribution` instances and a set of problems. The distributions returned should be such that they have the :attr:`required` attribute set to ``True`` if they were from the ``requirement`` passed to ``find()``, and they have the :attr:`build_time_dependency` attribute set to ``True`` unless they are post-installation dependencies of the ``requirement``. The problems should be a tuple consisting of the string ``'unsatisfied'`` and the requirement which couldn't be satisfied by any distribution known to the locator. """ self.provided = {} self.dists = {} self.dists_by_name = {} self.reqts = {} meta_extras = set(meta_extras or []) if ':*:' in meta_extras: meta_extras.remove(':*:') # :meta: and :run: are implicitly included meta_extras |= set([':test:', ':build:', ':dev:']) if isinstance(requirement, Distribution): dist = odist = requirement logger.debug('passed %s as requirement', odist) else: dist = odist = self.locator.locate(requirement, prereleases=prereleases) if dist is None: raise DistlibException('Unable to locate %r' % requirement) logger.debug('located %s', odist) dist.requested = True problems = set() todo = set([dist]) install_dists = set([odist]) while todo: dist = todo.pop() name = dist.key # case-insensitive if name not in self.dists_by_name: self.add_distribution(dist) else: #import pdb; pdb.set_trace() other = self.dists_by_name[name] if other != dist: self.try_to_replace(dist, other, problems) ireqts = dist.run_requires | dist.meta_requires sreqts = dist.build_requires ereqts = set() if meta_extras and dist in install_dists: for key in ('test', 'build', 'dev'): e = ':%s:' % key if e in meta_extras: ereqts |= getattr(dist, '%s_requires' % key) all_reqts = ireqts | sreqts | ereqts for r in all_reqts: providers = self.find_providers(r) if not providers: logger.debug('No providers found for %r', r) provider = self.locator.locate(r, prereleases=prereleases) # If no provider is found and we didn't consider # prereleases, consider them now. if provider is None and not prereleases: provider = self.locator.locate(r, prereleases=True) if provider is None: logger.debug('Cannot satisfy %r', r) problems.add(('unsatisfied', r)) else: n, v = provider.key, provider.version if (n, v) not in self.dists: todo.add(provider) providers.add(provider) if r in ireqts and dist in install_dists: install_dists.add(provider) logger.debug('Adding %s to install_dists', provider.name_and_version) for p in providers: name = p.key if name not in self.dists_by_name: self.reqts.setdefault(p, set()).add(r) else: other = self.dists_by_name[name] if other != p: # see if other can be replaced by p self.try_to_replace(p, other, problems) dists = set(self.dists.values()) for dist in dists: dist.build_time_dependency = dist not in install_dists if dist.build_time_dependency: logger.debug('%s is a build-time dependency only.', dist.name_and_version) logger.debug('find done for %s', odist) return dists, problems