Fall back to default when graph_reference fails.

This means we *never* throw an error. Order of priority:

1. we successfully check with the plotly api
2. check fails, but there’s a local backup
3. check fails and no local backup. we resort to default file

Author: theengineear

plotly/graph_reference.py

@@ -6,7 +6,9 @@
 
 import hashlib
 import json
+import os
 import requests
+from pkg_resources import resource_string
 
 import six
 
@@ -45,13 +47,9 @@ def get_graph_reference():
         response.raise_for_status()
     except requests.exceptions.RequestException:
         if not graph_reference:
-            raise exceptions.PlotlyError(
-                "The schema used to validate Plotly figures has never been "
-                "downloaded to your computer. You'll need to connect to a "
-                "Plotly server at least once to do this.\n"
-                "You're seeing this error because the attempt to download "
-                "the schema from '{}' failed.".format(graph_reference_url)
-            )
+            path = os.path.join('graph_reference', 'default-schema.json')
+            s = resource_string('plotly', path).decode('utf-8')
+            graph_reference = json.loads(s)
     else:
         if six.PY3:
             content = str(response.content, encoding='utf-8')

plotly/tests/test_core/test_graph_reference/test_graph_reference.py

@@ -3,8 +3,12 @@
 
 """
 from __future__ import absolute_import
+import json
 
-from plotly import exceptions, files, graph_reference as gr, tools, utils
+import os
+from pkg_resources import resource_string
+
+from plotly import files, graph_reference as gr, tools, utils
 from plotly.tests.utils import PlotlyTestCase
 
 
@@ -37,10 +41,13 @@ def test_get_graph_reference_bad_request_local_copy(self):
 
     def test_get_graph_reference_bad_request_no_copy(self):
 
-        # if we don't have a graph reference we *have* to error, no choice :(
+        # if we don't have a graph reference we load an outdated default
 
         tools.set_config_file(plotly_api_domain='api.am.not.here.ly')
         empty_graph_reference = {}  # set it to a false-y value.
         self.set_graph_reference(empty_graph_reference)
-        with self.assertRaisesRegexp(exceptions.PlotlyError, 'schema'):
-            gr.get_graph_reference()
+        path = os.path.join('graph_reference', 'default-schema.json')
+        s = resource_string('plotly', path).decode('utf-8')
+        default_graph_reference = json.loads(s)
+        graph_reference = gr.get_graph_reference()
+        self.assertEqual(graph_reference, default_graph_reference)