Add FIXME comment to Etag function

We are not using etag correctly. Also the function name is misleading
as we are checking the Etag in this create_etag function

Signed-off-by: Philippe Ombredanne <pombredanne@nexb.com>

Author: pombredanne

vulnerabilities/helpers.py

@@ -23,9 +23,9 @@
 import json
 import re
 
-import yaml
 import requests
 import toml
+import yaml
 
 # TODO add logging here
 
@@ -50,6 +50,13 @@ def fetch_yaml(url):
     return yaml.safe_load(response.content)
 
 
+# FIXME: this is NOT how etags work .
+# We should instead send the proper HTTP header
+# https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/If-None-Match
+# and integrate this finely in the processing as this typically needs to use
+# streaming=True requests, and proper handling of the HTTP return code
+# In all cases this ends up being a single request, not a HEADD followed
+# by another real request
 def create_etag(data_src, url, etag_key):
     """
     Etags are like hashes of web responses. For a data source `data_src`,