From 39d399b4b7a689dd379c56cc4e28afe065154046 Mon Sep 17 00:00:00 2001
From: sengian <sengian1@gmail.com>
Date: Sun, 16 Feb 2014 21:27:21 +0100
Subject: [PATCH] Add a DOI check function to metadata

---
 src/calibre/ebooks/metadata/__init__.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/calibre/ebooks/metadata/__init__.py b/src/calibre/ebooks/metadata/__init__.py
index 13b0b7daa5..8f8904554d 100644
--- a/src/calibre/ebooks/metadata/__init__.py
+++ b/src/calibre/ebooks/metadata/__init__.py
@@ -368,3 +368,11 @@ def format_isbn(isbn):
         return '-'.join((i[:2], i[2:6], i[6:9], i[9]))
     return '-'.join((i[:3], i[3:5], i[5:9], i[9:12], i[12]))
 
+def check_doi(doi):
+    if not doi:
+        return None
+    doi_check = re.search(r'10\.\d{4}/\S+', doi)
+    if doi_check is not None:
+        return doi_check.group()
+    return None
+