Use ua hash for smaller cache keys

Author: thinkwelltwd

device_detector/device_detector.py

@@ -30,7 +30,7 @@
     NameVersionExtractor,
     WholeNameExtractor,
 )
-from .settings import DDCache, WORTHLESS_UA_TYPES
+from .settings import DDCache, WORTHLESS_UA_TYPES, ua_hash
 from .yaml_loader import RegexLoader
 
 MAC_iOS = {
@@ -73,7 +73,7 @@ def __init__(self, user_agent, skip_bot_detection=False):
 
         # Holds the useragent that should be parsed
         self.user_agent = user_agent
-
+        self.ua_hash = ua_hash(self.user_agent)
         self.os = None
         self.client = None
         self.device = None
@@ -98,14 +98,15 @@ def class_name(self) -> str:
         return self.__class__.__name__
 
     def get_parse_cache(self):
-        if self.user_agent not in DDCache['user_agents']:
+        if self.ua_hash not in DDCache['user_agents']:
             return None
-        return DDCache['user_agents'][self.user_agent].get('parsed', None)
+        return DDCache['user_agents'][self.ua_hash].get('parsed', None)
 
     def set_parse_cache(self):
-        if self.user_agent not in DDCache['user_agents']:
-            DDCache['user_agents'][self.user_agent] = {}
-        DDCache['user_agents'][self.user_agent]['parsed'] = self
+        try:
+            DDCache['user_agents'][self.ua_hash]['parsed'] = self
+        except KeyError:
+            DDCache['user_agents'][self.ua_hash] = {'parsed': self}
         return self
 
     # -----------------------------------------------------------------------------

device_detector/parser/parser.py

@@ -5,6 +5,7 @@
 
 from ..settings import (
     DDCache,
+    ua_hash,
 )
 from .extractors import (
     NameExtractor,
@@ -30,13 +31,14 @@ def __init__(self, ua):
         else:
             self.user_agent = ua
 
+        self.ua_hash = ua_hash(self.user_agent)
         self.ua_data = {}
         self.app_name = ''
         self.app_name_no_punctuation = ''
         self.matched_regex = None
         self.known = False
-        if self.user_agent not in DDCache['user_agents']:
-            DDCache['user_agents'][self.user_agent] = {}
+        if self.ua_hash not in DDCache['user_agents']:
+            DDCache['user_agents'][self.ua_hash] = {}
 
     @property
     def cache_name(self) -> str:
@@ -50,10 +52,10 @@ def dtype(self) -> str:
         return self.cache_name.lower()
 
     def get_from_cache(self) -> dict:
-        return DDCache['user_agents'][self.user_agent].get(self.cache_name, None)
+        return DDCache['user_agents'][self.ua_hash].get(self.cache_name, None)
 
     def add_to_cache(self) -> dict:
-        DDCache['user_agents'][self.user_agent][self.cache_name] = self.ua_data
+        DDCache['user_agents'][self.ua_hash][self.cache_name] = self.ua_data
         return self.ua_data
 
     def _check_regex(self, regex):

device_detector/settings.py

@@ -1,8 +1,17 @@
 from collections import OrderedDict
 from copy import deepcopy
+from hashlib import md5
 import os
 
 
+def ua_hash(user_agent):
+    """
+    Return short hash of User Agent string for 
+    memory-efficient cache key.
+    """
+    return md5(user_agent.encode('utf-8')).hexdigest()[:9]
+
+
 # interpolate regex with anchors so
 # iPhone / Tiphone are matched correctly
 BOUNDED_REGEX = r'(?:^|[^A-Z0-9_\-])(?:{})'
@@ -85,4 +94,6 @@ def clear(self):
     'LRUDict',
     'ROOT',
     'WORTHLESS_UA_TYPES',
+    'ua_hash',
 )
+