Implement cache of login credentials.

Also add endpoints.ME to easily access the @me endpoint.

2 files changed, 50 insertions, 3 deletions

diff --git a/discord/client.py b/discord/client.py
index 42657f69..75b3c9a3 100644
--- a/discord/client.py
+++ b/discord/client.py
@@ -45,6 +45,7 @@ import websockets
 
 import logging, traceback
 import sys, time, re, json
+import tempfile, os, hashlib
 
 log = logging.getLogger(__name__)
 request_logging_format = '{method} {response.url} has returned {response.status}'
@@ -68,6 +69,10 @@ class Client:
     loop : Optional[event loop].
         The `event loop`_ to use for asynchronous operations. Defaults to ``None``,
         in which case the default event loop is used via ``asyncio.get_event_loop()``.
+    cache_auth : Optional[bool]
+        Indicates if :meth:`login` should cache the authentication tokens. Defaults
+        to ``True``. The method in which the cache is written is done by writing to
+        disk to a temporary directory.
 
     Attributes
     -----------
@@ -101,6 +106,7 @@ class Client:
         self.voice = None
         self.loop = asyncio.get_event_loop() if loop is None else loop
         self._listeners = []
+        self.cache_auth = options.get('cache_auth', True)
 
         max_messages = options.get('max_messages')
         if max_messages is None or max_messages < 100:
@@ -131,6 +137,10 @@ class Client:
 
     # internals
 
+    def _get_cache_filename(self, email):
+        filename = hashlib.md5(email.encode('utf-8')).hexdigest()
+        return os.path.join(tempfile.gettempdir(), 'discord_py', filename)
+
     def handle_message(self, message):
         removed = []
         for i, (condition, future) in enumerate(self._listeners):
@@ -510,6 +520,31 @@ class Client:
             usually when it isn't 200 or the known incorrect credentials
             passing status code.
         """
+
+        # attempt to read the token from cache
+        if self.cache_auth:
+            try:
+                log.info('attempting to login via cache')
+                cache_file = self._get_cache_filename(email)
+                with open(cache_file, 'r') as f:
+                    log.info('login cache file found')
+                    self.token = f.read()
+                    self.headers['authorization'] = self.token
+
+                check = yield from self.session.get(endpoints.ME, headers=self.headers)
+                if check.status == 200:
+                    log.info('login cache token check succeeded')
+                    yield from check.release()
+                    self._is_logged_in = True
+                    return
+
+                # at this point our check failed
+                # so we have to login and get the proper token and then
+                # redo the cache
+            except OSError as e:
+                log.info('a problem occurred while opening login cache')
+                pass # file not found et al
+
         payload = {
             'email': email,
             'password': password
@@ -531,6 +566,18 @@ class Client:
         self.headers['authorization'] = self.token
         self._is_logged_in = True
 
+        # since we went through all this trouble
+        # let's make sure we don't have to do it again
+        if self.cache_auth:
+            try:
+                os.makedirs(os.path.dirname(cache_file), exist_ok=True)
+                with open(cache_file, 'w') as f:
+                    log.info('updating login cache')
+                    f.write(self.token)
+            except OSError:
+                log.info('a problem occurred while updating the login cache')
+                pass
+
     @asyncio.coroutine
     def logout(self):
         """|coro|
@@ -683,7 +730,7 @@ class Client:
             'recipient_id': user.id
         }
 
-        url = '{}/@me/channels'.format(endpoints.USERS)
+        url = '{}/channels'.format(endpoints.ME)
         r = yield from self.session.post(url, data=utils.to_json(payload), headers=self.headers)
         log.debug(request_logging_format.format(method='POST', response=r))
         yield from utils._verify_successful_response(r)
@@ -1216,8 +1263,7 @@ class Client:
             'avatar': avatar
         }
 
-        url = '{0}/@me'.format(endpoints.USERS)
-        r = yield from self.session.patch(url, headers=self.headers, data=utils.to_json(payload))
+        r = yield from self.session.patch(endpoints.ME, headers=self.headers, data=utils.to_json(payload))
         log.debug(request_logging_format.format(method='PATCH', response=r))
         yield from utils._verify_successful_response(r)
 
diff --git a/discord/endpoints.py b/discord/endpoints.py
index 7266b775..d3e7f197 100644
--- a/discord/endpoints.py
+++ b/discord/endpoints.py
@@ -28,6 +28,7 @@ BASE          = 'https://discordapp.com'
 API_BASE      = BASE     + '/api'
 GATEWAY       = API_BASE + '/gateway'
 USERS         = API_BASE + '/users'
+ME            = USERS    + '/@me'
 REGISTER      = API_BASE + '/auth/register'
 LOGIN         = API_BASE + '/auth/login'
 LOGOUT        = API_BASE + '/auth/logout'