Allow HEAD to check if backup exists

get_backup

@@ -22,6 +22,15 @@ def get_backup_dir(backup_name):
     return backup_path
 
 
+def handle_head(backup_name):
+    try:
+        backup_path = get_backup_dir(backup_name)
+        start_response(extra_headers=['Content-length: 0'])
+    except:
+        start_response(status_code=("404", "Not Found",), extra_headers=['Content-length: 0'])
+    exit(0)
+
+
 def handle_get_rsync(backup_name):
     """
     Prints the absolute path an rsync backup should pull from
@@ -67,6 +76,11 @@ def handle_req():
         # Should respond by transferring tar.gz data
         handle_get_archive(params["name"])
     
+    elif os.environ['REQUEST_METHOD'] == "HEAD":
+        # Respond with 200 or 404 depending if backup exists
+        # TODO: deeper inspection so the headers can be flushed out
+        handle_head(params["name"])
+    
     else:
         raise Exception("Invalid request. Params: %s" % params)