I don't even

[librarian.git] / librarian / formats / cover / evens / __init__.py

diff --git a/librarian/formats/cover/evens/__init__.py b/librarian/formats/cover/evens/__init__.py
index e07f78b..c1229ad 100644 (file)
--- a/librarian/formats/cover/evens/__init__.py
+++ b/librarian/formats/cover/evens/__init__.py
@@ -27,6 +27,9 @@ class EvensCover(Cover):
             raise BuildError('No cover specified (metadata field relation.coverimage.url empty)')
         if cover_url.startswith('file://'):
             cover_url = ctx.files_path + urllib.quote(cover_url[7:])
+        IMG_EXT = ('png', 'jpg', 'jpeg', 'gif')
+        if '.' not in cover_url or cover_url.rsplit('.', 1)[1].lower() not in IMG_EXT:
+            raise BuildError('Wrong cover format, should be PNG, JPG or GIF')
         try:
             self.background_img = urlopen(cover_url)
         except URLError: