Check for content-type after headers dict has been populated

salt/utils/http.py

@@ -247,17 +247,6 @@ def query(
         else:
             http_proxy_url = f"http://{proxy_host}:{proxy_port}"
 
-        if header_dict is None:
-            header_dict = {}
-
-        if method == "POST" and "Content-Type" not in header_dict:
-            log.debug(
-                "Content-Type not provided for POST request, assuming application/x-www-form-urlencoded"
-            )
-            header_dict["Content-Type"] = "application/x-www-form-urlencoded"
-            if "Content-Length" not in header_dict:
-                header_dict["Content-Length"] = f"{len(data)}"
-
     match = re.match(
         r"https?://((25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(25[0-5]|2[0-4]\d|[01]?\d\d?)($|/)",
         url,
@@ -364,6 +353,19 @@ def query(
         agent = f"{agent} http.query()"
     header_dict["User-agent"] = agent
 
+    if (
+        proxy_host
+        and proxy_port
+        and method == "POST"
+        and "Content-Type" not in header_dict
+    ):
+        log.debug(
+            "Content-Type not provided for POST request, assuming application/x-www-form-urlencoded"
+        )
+        header_dict["Content-Type"] = "application/x-www-form-urlencoded"
+        if "Content-Length" not in header_dict:
+            header_dict["Content-Length"] = f"{len(data)}"
+
     if backend == "requests":
         sess = requests.Session()
         sess.auth = auth