Register the endpoints list without a trailing slash, and stop hiding its errors

plugins/endpoints/api/routes.py

@@ -55,11 +55,25 @@ def _format_uptime(seconds):
 # Endpoint state
 # =============================================================================
 
-@endpoints_bp.route('/', methods=['GET'])
+@endpoints_bp.route('', methods=['GET'])
 @require_permission('endpoints.view')
 def list_endpoints():
     """List reported endpoint states.
 
+    Registered as '' so the rule is '/api/endpoints', with no trailing slash.
+    CONTRIBUTING.md's API section spells endpoints that way ('/api/machines'),
+    and every other plugin's list route follows it - this was the only route in
+    331 paths that did not.
+
+    It was not cosmetic. A rule ending in a slash makes Flask answer the
+    unslashed URL with a 308 to an ABSOLUTE url. On dev that resolves and
+    nobody notices. Behind the IIS subpath it does not: with no ProxyFix,
+    Werkzeug builds that Location from the scheme and host it believes it has,
+    so it emitted http:// and dropped the /shopdb prefix. The browser refuses
+    to follow an https page to http, the list request failed, and the page
+    rendered "No endpoints found" - indistinguishable from a fleet with nothing
+    in it. The agent had been reporting correctly the whole time.
+
     Joins through Computer so each row carries computerid and can deep-link
     into the existing PC detail page (/pcs/{computerid}). Endpoint state only
     exists for hostnames resolved to a Computer, so the join is not lossy.