error message phrasing, add guard to token,

Author: snbianco

astroquery/mast/missions.py

@@ -771,9 +771,9 @@ def _warn_no_auth(self, download_url):
         download_url : str
             The URL that the user attempted to download from, which requires authentication.
         """
-        no_auth_msg = f'You are not authorized to download from {download_url}.'
+        no_auth_msg = f'You are not authorized to access {download_url}.'
         if self._authenticated:
-            no_auth_msg += ('\nYou do not have access to download this data, or your authentication '
+            no_auth_msg += ('\nYou do not have access to this data, or your authentication '
                             'token may be expired. You can generate a new token at '
                             'https://auth.mast.stsci.edu/token?suggested_name=Astroquery&'
                             'suggested_scope=mast:exclusive_access')
@@ -1026,7 +1026,9 @@ def read_product(self, uri, *, mission=None, **kwargs):
                                       '`pip install astroquery[all]`.', ImportWarning)
 
                 # Make an authenticated request to get the presigned S3 URL for the ASDF file
-                headers = {"Authorization": f"token {self._auth_obj.session.cookies['mast_token']}"}
+                headers = {}
+                if self._authenticated:
+                    headers["Authorization"] = f"token {self._auth_obj.session.cookies['mast_token']}"
                 resp = requests.get(
                     download_url,
                     headers=headers,

astroquery/mast/tests/test_mast.py

@@ -709,8 +709,8 @@ def test_missions_download_no_auth(caplog):
         msg = str(warn_auth[0].message)
     assert result[0] == 'ERROR'
     assert 'HTTPError' in result[1]
-    assert 'You are not authorized to download' in msg
-    assert 'You do not have access to download this data' in msg
+    assert 'You are not authorized to access' in msg
+    assert 'You do not have access to this data' in msg
 
 
 def test_missions_get_dataset_kwd(caplog):