Added BearerAuth class to leverage requests.auth

Author: OffBy0x01

blackduck/Authentication.py

@@ -1,7 +1,95 @@
-import logging
+'''
+
+Created on Dec 23, 2020
+@author: ar-calder
+
+'''
+ 
 import requests
+import logging
 import json
-from operator import itemgetter
-import urllib.parse
+from datetime import datetime, timedelta
+
+logger = logging.getLogger(__name__)
+
+class BearerAuth(requests.auth.AuthBase):
+    
+    from .Exceptions import http_exception_handler
+
+    def __init__(
+        self,
+        session=None,
+        token=None,
+        base_url=None,
+        verify=True,
+        timeout=15,
+        ):
+
+        if any(arg == False for arg in (token, base_url)):
+            raise ValueError(
+                'token & base_url are required'
+            )
+
+        self.verify=verify
+        self.client_token = token
+        self.auth_token = None
+        self.csrf_token = None
+        self.valid_until = datetime.utcnow()
+
+        self.auth_url = requests.compat.urljoin(base_url, '/api/tokens/authenticate')
+        self.session = session or requests.session()
+        self.timeout = timeout        
+
+
+    def __call__(self, request):
+        if not self.auth_token or self.valid_until < datetime.utcnow():
+            # If authentication token not set or no longer valid
+            self.authenticate()
+
+        request.headers.update({ 
+            "authorization" : f"bearer {self.auth_token}",
+            "X-CSRF-TOKEN" : self.csrf_token
+        })
+
+        return request
+
+
+    def authenticate(self):
+        if not self.verify:
+            requests.packages.urllib3.disable_warnings()
+            # Announce this on every auth attempt, as a little incentive to properly configure certs
+            logger.warn("ssl verification disabled, connection insecure. do NOT use verify=False in production!")
+            
+        try:
+            response = self.session.request(
+                method='POST',
+                url=self.auth_url,
+                headers = {
+                    "Authorization" : f"token {self.client_token}"
+                },
+                verify=self.verify,
+                timeout=self.timeout
+            )
+
+            if response.status_code / 100 != 2:
+                self.http_exception_handler(
+                    response=response,
+                    name="authenticate"
+                )
+
+            content = response.json()
+            self.csrf_token = response.headers.get('X-CSRF-TOKEN')
+            self.auth_token = content.get('bearerToken')
+            self.valid_until = datetime.utcnow() + timedelta(milliseconds=int(content.get('expiresInMilliseconds', 0)))
 
-logger = logging.getLogger(__name__)
+        # Do not handle exceptions - just just more details as to possible causes
+        # Thus we do not catch a JsonDecodeError here even though it may occur
+        # - no futher details to give.  
+        except requests.exceptions.ConnectTimeout as connect_timeout:
+            logger.critical(f"could not establish a connection within {self.timeout}s, this may be indicative of proxy misconfiguration")
+            raise connect_timeout
+        except requests.exceptions.ReadTimeout as read_timeout:
+            logger.critical(f"slow or unstable connection, consider increasing timeout (currently set to {self.timeout}s)")
+            raise read_timeout
+        else:
+            logger.info(f"success: auth granted until {self.valid_until} UTC")