fix #35

Also add an option `direct-reply` to control the number of comments
on a thread without referencing a child (to avoid a simple while loop
that `curl -XPOST ...` the url).

Defaults to 3, that means a /24 (or /48 for IPv6) address can only post
3 direct responses on a thread at all.

docs/CONFIGURATION.rst

@@ -186,14 +186,19 @@ for IPv4, ``/48`` for IPv6).
     [guard]
     enabled = true
     ratelimit = 2
+    direct-reply = 3
 
 enabled
     enable guard, recommended in production. Not useful for debugging
     purposes.
 
-ratelimit: N
+ratelimit
     limit to N new comments per minute.
 
+direct-reply
+    how many comments directly to the thread (prevent a simple
+    `while true; do curl ...; done`.
+
 
 Appendum
 ---------

isso/core.py

@@ -119,8 +119,8 @@ class Config:
         "to = ", "from = ",
         "[guard]",
         "enabled = true",
-        "ratelimit = 2"
-        ""
+        "ratelimit = 2",
+        "direct-reply = 3"
     ]
 
     @classmethod

isso/db/__init__.py

@@ -2,11 +2,9 @@
 
 import sqlite3
 
-class IssoDBException(Exception):
-    pass
-
 from isso.db.comments import Comments
 from isso.db.threads import Threads
+from isso.db.spam import Guard
 
 
 class SQLite3:
@@ -19,6 +17,7 @@ class SQLite3:
 
         self.threads = Threads(self)
         self.comments = Comments(self)
+        self.guard = Guard(self)
 
         self.execute([
             'CREATE TRIGGER IF NOT EXISTS remove_stale_threads',

isso/db/comments.py

@@ -33,7 +33,6 @@ class Comments:
             '    text VARCHAR, author VARCHAR, email VARCHAR, website VARCHAR,',
             '    likes INTEGER DEFAULT 0, dislikes INTEGER DEFAULT 0, voters BLOB NOT NULL);'])
 
-    @spam.check
     def add(self, uri, c):
         """
         Add a new comment to the database and return public fields as dict.

isso/db/spam.py

@@ -1,47 +1,55 @@
 # -*- encoding: utf-8 -*-
 
 import time
-
-from isso.db import IssoDBException
+import functools
 
 
-class TooManyComments(IssoDBException):
-    pass
+class Guard:
 
+    def __init__(self, db):
 
-def check(func):
+        self.db = db
+        self.conf = db.conf.section("guard")
 
-    def dec(self, uri, c):
+    def validate(self, uri, comment):
 
-        if not self.db.conf.getboolean("guard", "enabled"):
-            return func(self, uri, c)
+        if not self.conf.getboolean("enabled"):
+            return True, ""
 
-        # block more than two comments per minute
+        for func in (self._limit, self._spam):
+            valid, reason = func(uri, comment)
+            if not valid:
+                return False, reason
+        return True, ""
+
+    @classmethod
+    def ids(cls, rv):
+        return [str(col[0]) for col in rv]
+
+    def _limit(self, uri, comment):
+
+        # block more than :param:`ratelimit` comments per minute
         rv = self.db.execute([
-            'SELECT id FROM comments WHERE remote_addr = ? AND created > ?;'
-        ], (c["remote_addr"], time.time() + 60)).fetchall()
+            'SELECT id FROM comments WHERE remote_addr = ? AND ? - created < 60;'
+        ], (comment["remote_addr"], time.time())).fetchall()
 
-        if len(rv) >= self.db.conf.getint("guard", "ratelimit"):
-            raise TooManyComments
+        if len(rv) >= self.conf.getint("ratelimit"):
+            return False, "{0}: ratelimit exceeded ({1})".format(
+                comment["remote_addr"], ', '.join(Guard.ids(rv)))
 
         # block more than three comments as direct response to the post
-        rv = self.db.execute([
-            'SELECT id FROM comments WHERE remote_addr = ? AND parent IS NULL;'
-        ], (c["remote_addr"], )).fetchall()
-
-        if len(rv) >= 3:
-            raise TooManyComments
-
-        # block reply to own comment if the cookie is still available (max age)
-        if "parent" in c:
+        if comment["parent"] is None:
             rv = self.db.execute([
-                'SELECT id FROM comments WHERE remote_addr = ? AND id = ? AND ? - created < ?;'
-            ], (c["remote_addr"], c["parent"], time.time(),
-                self.db.conf.getint("general", "max-age"))).fetchall()
+                'SELECT id FROM comments WHERE',
+                '    tid = (SELECT id FROM threads WHERE uri = ?)',
+                'AND remote_addr = ?',
+                'AND parent IS NULL;'
+            ], (uri, comment["remote_addr"])).fetchall()
 
-            if len(rv) > 0:
-                raise TooManyComments
+            if len(rv) >= self.conf.getint("direct-reply"):
+                return False, "%i direct responses to %s" % (len(rv), uri)
 
-        return func(self, uri, c)
+        return True, ""
 
-    return dec
+    def _spam(self, uri, comment):
+        return True, ""

isso/views/comments.py

@@ -15,7 +15,7 @@ from werkzeug.exceptions import BadRequest, Forbidden, NotFound
 
 from isso.compat import text_type as str
 
-from isso import utils, local
+from isso import utils, local, db
 from isso.utils import http, parse, markdown
 from isso.utils.crypto import pbkdf2
 from isso.views import requires
@@ -61,6 +61,7 @@ class API(object):
         self.conf = isso.conf.section("general")
         self.moderated = isso.conf.getboolean("moderation", "enabled")
 
+        self.guard = isso.db.guard
         self.threads = isso.db.threads
         self.comments = isso.db.comments
 
@@ -127,8 +128,10 @@ class API(object):
         # notify extensions that the new comment is about to save
         self.signal("comments.new:before-save", thread, data)
 
-        if data is None:
-            raise Forbidden
+        valid, reason = self.guard.validate(uri, data)
+        if not valid:
+            self.signal("comments.new:guard", reason)
+            raise Forbidden(reason)
 
         with self.isso.lock:
             rv = self.comments.add(uri, data)