allow for binary base64 encoding

nbconvert/exporters/html.py

@@ -12,6 +12,7 @@
 from traitlets.config import Config
 from jupyter_core.paths import jupyter_path
 from jinja2 import contextfilter
+from jinja2.loaders import split_template_path
 import jinja2
 
 from nbconvert.filters.highlight import Highlight2HTML
@@ -112,10 +113,26 @@ def resources_include_js(name):
         def resources_include_url(name):
             env = self.environment
             mime_type, encoding = mimetypes.guess_type(name)
-            data = env.loader.get_source(env, name)[0]
-            data = base64.b64encode(data.encode('utf8'))
+            try:
+                # we try to load via the jinja loader, but that tries to load
+                # as (encoded) text
+                data = env.loader.get_source(env, name)[0].encode('utf8')
+            except UnicodeDecodeError:
+                # if that fails (for instance a binary file, png or ttf)
+                # we mimic jinja2
+                pieces = split_template_path(name)
+                searchpaths = self.get_template_paths()
+                for searchpath in searchpaths:
+                    filename = os.path.join(searchpath, *pieces)
+                    print(filename, os.path.exists(filename))
+                    if os.path.exists(filename):
+                        with open(filename, "rb") as f:
+                            data = f.read()
+                            break
+                else:
+                    raise ValueError("No file %r found in %r" % (name, searchpaths))
+            data = base64.b64encode(data)
             data = data.replace(b'\n', b'').decode('ascii')
-            print(type(data), data)
             src = 'data:{mime_type};base64,{data}'.format(mime_type=mime_type, data=data)
             return jinja2.Markup(src)
         resources = super(HTMLExporter, self)._init_resources(resources)