From 08c9bd84d8b8dfcbc1563b1f5f2a13b3d19d1b11 Mon Sep 17 00:00:00 2001
From: wordofglass <wordofglass@users.noreply.github.com>
Date: Tue, 21 Jun 2016 02:30:20 +0200
Subject: [PATCH 1/3] fetchart: testcase for wrong server-side extensions
 (#2053)

---
 test/test_art.py | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/test/test_art.py b/test/test_art.py
index f88f2f1cf..58b15d8e5 100644
--- a/test/test_art.py
+++ b/test/test_art.py
@@ -46,7 +46,7 @@ class UseThePlugin(_common.TestCase):
 
 
 class FetchImageTest(UseThePlugin):
-    URL = 'http://example.com'
+    URL = 'http://example.com/test.jpg'
 
     @responses.activate
     def run(self, *args, **kwargs):
@@ -61,18 +61,23 @@ class FetchImageTest(UseThePlugin):
         self.dpath = os.path.join(self.temp_dir, b'arttest')
         self.source = fetchart.RemoteArtSource(logger, self.plugin.config)
         self.extra = {'maxwidth': 0}
+        self.candidate = fetchart.Candidate(logger, url=self.URL)
 
     def test_invalid_type_returns_none(self):
         self.mock_response('image/watercolour')
-        candidate = fetchart.Candidate(logger, url=self.URL)
-        self.source.fetch_image(candidate, self.extra)
-        self.assertEqual(candidate.path, None)
+        self.source.fetch_image(self.candidate, self.extra)
+        self.assertEqual(self.candidate.path, None)
 
     def test_jpeg_type_returns_path(self):
         self.mock_response('image/jpeg')
-        candidate = fetchart.Candidate(logger, url=self.URL)
-        self.source.fetch_image(candidate, self.extra)
-        self.assertNotEqual(candidate.path, None)
+        self.source.fetch_image(self.candidate, self.extra)
+        self.assertNotEqual(self.candidate.path, None)
+
+    def test_extension_set_by_content_type(self):
+        self.mock_response('image/png')
+        self.source.fetch_image(self.candidate, self.extra)
+        self.assertEqual(os.path.splitext(self.candidate.path)[1], b'.png')
+        self.assertExists(self.candidate.path)
 
 
 class FSArtTest(UseThePlugin):

From c4617c2c1fb4b64a1317f73350ebe2170d2262d0 Mon Sep 17 00:00:00 2001
From: wordofglass <wordofglass@users.noreply.github.com>
Date: Tue, 21 Jun 2016 10:57:45 +0200
Subject: [PATCH 2/3] fetchart: do not hardcode the downloaded extension to
 jpg, fixes #2053

---
 beetsplug/fetchart.py | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/beetsplug/fetchart.py b/beetsplug/fetchart.py
index 7f40e83f6..e10a35270 100644
--- a/beetsplug/fetchart.py
+++ b/beetsplug/fetchart.py
@@ -39,9 +39,11 @@ try:
 except ImportError:
     HAVE_ITUNES = False
 
-IMAGE_EXTENSIONS = ['png', 'jpg', 'jpeg']
-CONTENT_TYPES = ('image/jpeg', 'image/png')
-DOWNLOAD_EXTENSION = '.jpg'
+CONTENT_TYPES = {
+    'image/jpeg': [b'jpg', b'jpeg'],
+    'image/png': [b'png']
+}
+IMAGE_EXTENSIONS = [ext for exts in CONTENT_TYPES.values() for ext in exts]
 
 
 class Candidate(object):
@@ -227,8 +229,8 @@ class RemoteArtSource(ArtSource):
         try:
             with closing(self.request(candidate.url, stream=True,
                                       message=u'downloading image')) as resp:
-                if 'Content-Type' not in resp.headers \
-                        or resp.headers['Content-Type'] not in CONTENT_TYPES:
+                ct = resp.headers.get('Content-Type', None)
+                if ct not in CONTENT_TYPES:
                     self._log.debug(
                         u'not a supported image: {}',
                         resp.headers.get('Content-Type') or u'no content type',
@@ -237,7 +239,7 @@ class RemoteArtSource(ArtSource):
                     return
 
                 # Generate a temporary file with the correct extension.
-                with NamedTemporaryFile(suffix=DOWNLOAD_EXTENSION,
+                with NamedTemporaryFile(suffix=b'.' + CONTENT_TYPES[ct][0],
                                         delete=False) as fh:
                     for chunk in resp.iter_content(chunk_size=1024):
                         fh.write(chunk)

From f07e6265ee59b5410da2678f46974a57d20edcf3 Mon Sep 17 00:00:00 2001
From: wordofglass <wordofglass@users.noreply.github.com>
Date: Wed, 22 Jun 2016 13:02:15 +0200
Subject: [PATCH 3/3] Changelog for the Content-Type based image extension
 detection

---
 docs/changelog.rst | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/docs/changelog.rst b/docs/changelog.rst
index 6f0333582..567927a1d 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -34,6 +34,10 @@ Fixes:
   installations. Thanks to :user:`bismark`. :bug:`2038`
 * Fix a crash introduced in the previous version when the standard input was
   connected to a Unix pipe. :bug:`2041`
+* :doc:`/plugins/fetchart`: Determine the file extension for downloaded images
+  based on the ``Content-Type`` header instead of hardcoding it to .jpg.
+  Reported in :bug:`2053`, which for now it does not fix due to
+  server-side issues, though.
 
 1.3.18 (May 31, 2016)
 ---------------------