Require an already created session to be passed into APIs

pip/download.py

@@ -213,7 +213,9 @@ def get_file_content(url, comes_from=None, session=None):
     """Gets the content of a file; it may be a filename, file: URL, or
     http: URL.  Returns (location, content).  Content is unicode."""
     if session is None:
-        session = PipSession()
+        raise TypeError(
+            "get_file_content() missing 1 required keyword argument: 'session'"
+        )
 
     match = _scheme_re.search(url)
     if match:
@@ -494,7 +496,9 @@ def _copy_file(filename, location, content_type, link):
 def unpack_http_url(link, location, download_cache, download_dir=None,
                     session=None):
     if session is None:
-        session = PipSession()
+        raise TypeError(
+            "unpack_http_url() missing 1 required keyword argument: 'session'"
+        )
 
     temp_dir = tempfile.mkdtemp('-unpack', 'pip-')
     temp_location = None

pip/index.py

@@ -13,7 +13,7 @@
     UnsupportedWheel,
 )
 from pip.backwardcompat import urlparse, url2pathname
-from pip.download import PipSession, url_to_path, path_to_url
+from pip.download import url_to_path, path_to_url
 from pip.wheel import Wheel, wheel_ext
 from pip.pep425tags import supported_tags, supported_tags_noarch, get_platform
 from pip._vendor import html5lib, requests, pkg_resources
@@ -39,6 +39,12 @@ def __init__(self, find_links, index_urls,
                  use_wheel=True, allow_external=[], allow_unverified=[],
                  allow_all_external=False, allow_all_prereleases=False,
                  session=None):
+        if session is None:
+            raise TypeError(
+                "PackageFinder() missing 1 required keyword argument: "
+                "'session'"
+            )
+
         self.find_links = find_links
         self.index_urls = index_urls
         self.cache = PageCache()
@@ -73,7 +79,7 @@ def __init__(self, find_links, index_urls,
         self.allow_all_prereleases = allow_all_prereleases
 
         # The Session we'll use to make requests
-        self.session = session or PipSession()
+        self.session = session
 
     def _sort_locations(self, locations):
         """
@@ -717,7 +723,9 @@ def __str__(self):
     @classmethod
     def get_page(cls, link, req, cache=None, skip_archives=True, session=None):
         if session is None:
-            session = PipSession()
+            raise TypeError(
+                "get_page() missing 1 required keyword argument: 'session'"
+            )
 
         url = link.url
         url = url.split('#', 1)[0]
@@ -827,11 +835,8 @@ def _handle_fail(req, link, reason, url, cache=None, level=1, meth=None):
             cache.add_page_failure(url, level)
 
     @staticmethod
-    def _get_content_type(url, session=None):
+    def _get_content_type(url, session):
         """Get the Content-Type of the given url, using a HEAD request"""
-        if session is None:
-            session = PipSession()
-
         scheme, netloc, path, query, fragment = urlparse.urlsplit(url)
         if scheme not in ('http', 'https', 'ftp', 'ftps'):
             # FIXME: some warning or something?

pip/req/req_file.py

@@ -2,7 +2,7 @@
 import re
 
 from pip.backwardcompat import urlparse
-from pip.download import PipSession, get_file_content
+from pip.download import get_file_content
 from pip.req.req_install import InstallRequirement
 from pip.util import normalize_name
 
@@ -12,7 +12,10 @@
 def parse_requirements(filename, finder=None, comes_from=None, options=None,
                        session=None):
     if session is None:
-        session = PipSession()
+        raise TypeError(
+            "parse_requirements() missing 1 required keyword argument: "
+            "'session'"
+        )
 
     skip_match = None
     skip_regex = options.skip_requirements_regex if options else None

pip/req/req_set.py

@@ -4,7 +4,7 @@
 
 from pip._vendor import pkg_resources
 from pip.backwardcompat import HTTPError
-from pip.download import (PipSession, url_to_path, unpack_vcs_link, is_vcs_url,
+from pip.download import (url_to_path, unpack_vcs_link, is_vcs_url,
                           is_file_url, unpack_file_url, unpack_http_url)
 from pip.exceptions import (InstallationError, BestVersionAlreadyInstalled,
                             DistributionNotFound, PreviousBuildDirError)
@@ -54,6 +54,12 @@ def __init__(self, build_dir, src_dir, download_dir, download_cache=None,
                  target_dir=None, ignore_dependencies=False,
                  force_reinstall=False, use_user_site=False, session=None,
                  pycompile=True, wheel_download_dir=None):
+        if session is None:
+            raise TypeError(
+                "RequirementSet() missing 1 required keyword argument: "
+                "'session'"
+            )
+
         self.build_dir = build_dir
         self.src_dir = src_dir
         self.download_dir = download_dir
@@ -74,7 +80,7 @@ def __init__(self, build_dir, src_dir, download_dir, download_cache=None,
         self.as_egg = as_egg
         self.use_user_site = use_user_site
         self.target_dir = target_dir  # set from --target option
-        self.session = session or PipSession()
+        self.session = session
         self.pycompile = pycompile
         self.wheel_download_dir = wheel_download_dir