From 3281c40e6cbb412db7bf224ce800d4b25efb13ae Mon Sep 17 00:00:00 2001
From: Nichlas Severinsen <ns@nsz.no>
Date: Thu, 4 Jun 2020 21:53:33 +0200
Subject: [PATCH] Add naive link duplication prevention

---
 freepost/__init__.py |  3 +++
 freepost/database.py | 19 +++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/freepost/__init__.py b/freepost/__init__.py
index 29c8dfb0..157c763c 100755
--- a/freepost/__init__.py
+++ b/freepost/__init__.py
@@ -661,6 +661,9 @@ def submit_check ():
     # If there is a URL, make sure it has a "scheme"
     if len (link) > 0 and urlparse (link).scheme == '':
         link = 'http://' + link
+
+        if database.post_exists(link):
+            return template ('submit.html', flash='Link has already been submitted.')
     
     # Retrieve topics
     topics = request.forms.getunicode ('topics')
diff --git a/freepost/database.py b/freepost/database.py
index 1a883526..be034770 100644
--- a/freepost/database.py
+++ b/freepost/database.py
@@ -97,6 +97,25 @@ def username_exists (username, case_sensitive = True):
             
         return cursor.fetchone() is not None
 
+# Check if post with same link exists
+def post_exists (link):
+    if not link:
+        return None
+
+    with db:
+        cursor = db.execute(
+            """
+            SELECT *
+            FROM post
+            WHERE LOWER(link) = LOWER(:link)
+            """,
+            {
+                'link': link
+            }
+        )
+
+        return cursor.fetchone() is not None
+
 # Create new user account
 def new_user (username, password):
     # Create a hash_id for the new post