Add cookie jar

PFERD/cookie_jar.py

@@ -0,0 +1,57 @@
+import logging
+from http.cookiejar import LoadError, LWPCookieJar
+from pathlib import Path
+from typing import Optional
+
+import requests
+
+logger = logging.getLogger(__name__)
+
+class CookieJar:
+
+    def __init__(self, cookie_file: Optional[Path] = None) -> None:
+        self._cookies: LWPCookieJar
+        if cookie_file is None:
+            self._cookies = LWPCookieJar()
+        else:
+            self._cookies = LWPCookieJar(cookie_file)
+
+    @property
+    def cookies(self) -> LWPCookieJar:
+        return self._cookies
+
+    def load_cookies(self) -> None:
+        if self._cookies.filename is None:
+            return
+
+        try:
+            logger.info(f"Loading old cookies from {self._cookies.filename}")
+            self._cookies.load(ignore_discard=True)
+        except (FileNotFoundError, LoadError):
+            logger.warn(
+                f"No valid cookie file found at {self._cookies.filename}, "
+                "continuing with no cookies"
+            )
+
+    def save_cookies(self, reason: Optional[str] = None) -> None:
+        if self._cookies.filename is None:
+            return
+
+        if reason is None:
+            logger.info("Saving cookies")
+        else:
+            logger.info(f"Saving cookies ({reason})")
+
+        # TODO figure out why ignore_discard is set
+        # TODO possibly catch a few more exceptions
+        self._cookies.save(ignore_discard=True)
+
+    def create_session(self) -> requests.Session:
+        sess = requests.Session()
+
+        # From the request docs: "All requests code should work out of the box
+        # with externally provided instances of CookieJar, e.g. LWPCookieJar
+        # and FileCookieJar."
+        sess.cookies = self.cookies # type: ignore
+
+        return sess