check if url exists before creating a comment

isso/__init__.py

@@ -53,16 +53,19 @@ url_map = Map([
 
 class Isso:
 
+    PRODUCTION = True
     SECRET_KEY = ',\x1e\xbaY\xbb\xdf\xe7@\x85\xe3\xd9\xb4A9\xe4G\xa6O'
     MODERATION = False
     SQLITE = None
 
+    HOST = 'http://localhost:8000/'
     MAX_AGE = 15*60
 
     def __init__(self, conf):
 
         self.__dict__.update(dict((k, v) for k, v in conf.iteritems() if k.isupper()))
         self.signer = URLSafeTimedSerializer(self.SECRET_KEY)
+        self.HOST = utils.determine(self.HOST)
 
         if self.SQLITE:
             self.db = db.SQLite(self)

isso/comment.py

@@ -8,15 +8,18 @@ from werkzeug.exceptions import abort
 
 from itsdangerous import SignatureExpired, BadSignature
 
-from isso import json, models
+from isso import json, models, utils
 
 
 def create(app, environ, request, path):
 
+    if app.PRODUCTION and not utils.urlexists(app.HOST, path):
+        return abort(404)
+
     try:
         rv = app.db.add(path, models.Comment.fromjson(request.data))
-    except ValueError as e:
-        return Response(unicode(e), 400)
+    except ValueError:
+        return abort(400)
 
     response = Response(json.dumps(rv), 201, content_type='application/json')
     response.set_cookie('session', app.signer.dumps([path, rv.id]), max_age=app.MAX_AGE)

isso/utils.py

@@ -4,6 +4,11 @@
 # License: BSD Style, 2 clauses. see isso/__init__.py
 
 import json
+import socket
+import httplib
+import urlparse
+import contextlib
+
 from isso.models import Comment
 
 
@@ -14,3 +19,21 @@ class IssoEncoder(json.JSONEncoder):
             return dict((field, value) for field, value in obj.iteritems())
 
         return json.JSONEncoder.default(self, obj)
+
+
+def urlexists(host, path):
+    with contextlib.closing(httplib.HTTPConnection(host)) as con:
+        try:
+            con.request('HEAD', path)
+        except socket.error:
+            return False
+        return con.getresponse().status == 200
+
+
+def determine(host):
+    """Make `host` compatible with :py:mod:`httplib`."""
+
+    if not host.startswith(('http://', 'https://')):
+        host = 'http://' + host
+    rv = urlparse.urlparse(host)
+    return (rv.netloc + ':443') if rv.scheme == 'https' else rv.netloc

specs/test_comment.py

@@ -17,7 +17,7 @@ class TestComments(unittest.TestCase):
 
     def setUp(self):
         fd, self.path = tempfile.mkstemp()
-        self.app = Isso({'SQLITE': self.path})
+        self.app = Isso({'SQLITE': self.path, 'PRODUCTION': False})
 
         self.client = Client(self.app, Response)
         self.get = lambda *x, **z: self.client.get(*x, **z)