README: Add crate layout guide

2 files changed, 62 insertions, 2 deletions

diff --git a/README.rst b/README.rst
index f0a5269..6b3caac 100644
--- a/README.rst
+++ b/README.rst
@@ -27,7 +27,18 @@ Each bottle contains a LED with a WS2801 driver. Each crate contains a chain of
 2. Poke a 12mm hole in the lid
 3. Put it in a crate
 4. Repeat from step 1
-5. Stick a loop of LEDs through the lids of the bottles
+5. Stick a loop of LEDs through the lids of the bottles like this:
+   .. code::
+             ┏━━━┯━━━┯━━━┯━━━┯━━━┓
+     {start}→┃ ○ → ○ → ○ → ○ → ○ ┃
+             ┠───┼───┼───┼───┼─↓─┨
+     {  end}←┃ ○ │ ○ ← ○ ← ○ ← ○ ┃
+             ┠─↑─┼─↓─┼───┼───┼───┨
+             ┃ ○ │ ○ → ○ → ○ → ○ ┃
+             ┠─↑─┼───┼───┼───┼─↓─┨
+             ┃ ○ ← ○ ← ○ ← ○ ← ○ ┃
+             ┗━━━┷━━━┷━━━┷━━━┷━━━┛
+
 6. Repeat from step 1
 7. Stack up a bunch of these crates and tie them together with zip ties and straps
 8. Connect all the wires together (mis-)using wonderful XLR connectors
diff --git a/host/secret_sauce.py b/host/secret_sauce.py
index bf183ac..3682b0e 100644
--- a/host/secret_sauce.py
+++ b/host/secret_sauce.py
@@ -1,7 +1,56 @@
 
+from collections import defaultdict
+import signal
+
+
+RATELIMIT_THRESHOLD = 20
+GRAYLIST_LENGTH = 8
+
 class SpamError(ValueError):
     def __str__(self):
         return ' '.join(self.args)
 
+
+def loadlist(fn):
+	try:
+		with open(fn) as f:
+			return [ l for l in ( l.strip() for l in f.readlines() if not l.startswith('#')) if l ]
+	except:
+		return []
+
+greenlist = set()
+
+graylist = []
+def do_graylist(msg):
+    global graylist
+    graylist = [msg] + graylist[:GRAYLIST_LENGTH-1]
+
+blacklist = loadlist('blacklist')
+badwords = loadlist('badwords')
+def signal_handler(_signum, _frame):
+    global blacklist, badwords
+    blacklist = load_blacklist()
+    badwords = load_badwords()
+signal.signal(signal.SIGHUP, signal_handler)
+
+ratelimitdict = defaultdict(lambda: 0)
+def empty_ratelimit(_signum, _frame):
+	global ratelimitdict
+	ratelimitdict = defaultdict(lambda: 0)
+signal.signal(signal.SIGALRM, empty_ratelimit)
+signal.setitimer(signal.ITIMER_REAL, 60)
+
 def check_spam(addr, data):
-	pass
+	ratelimitdict[addr] += 1
+	try:
+		if ratelimitdict[addr] > RATELIMIT_THRESHOLD:
+			raise SpamError('rate-limit')
+		if any(word in data.lower() for word in badwords):
+			raise SpamError('badwords filter')
+		if addr not in greenlist and data in graylist:
+			raise SpamError('graylist')
+	except SpamError as err:
+		do_graylist(data)
+		blacklist.append(addr)
+		raise err
+	greenlist.add(addr)