Decode bytes in bokeh plots (#2357)

holoviews/plotting/bokeh/element.py

@@ -25,7 +25,8 @@
 from ..util import dynamic_update, process_cmap
 from .plot import BokehPlot, TOOLS
 from .util import (mpl_to_bokeh, get_tab_title,  py2js_tickformatter,
-                   rgba_tuple, recursive_model_update, glyph_order)
+                   rgba_tuple, recursive_model_update, glyph_order,
+                   decode_bytes)
 
 property_prefixes = ['selection', 'nonselection', 'muted', 'hover']
 
@@ -571,7 +572,7 @@ def _update_range(self, axis_range, low, high, factors, invert, shared, log, str
                 if streaming:
                     axis_range.trigger(k, old, new)
         elif isinstance(axis_range, FactorRange):
-            factors = list(factors)
+            factors = list(decode_bytes(factors))
             if invert: factors = factors[::-1]
             axis_range.factors = factors
 
@@ -1156,6 +1157,7 @@ def _get_cmapper_opts(self, low, high, factors, colors):
             opts.update({opt: colors[name] for name, opt in color_opts if name in colors})
         else:
             colormapper = CategoricalColorMapper
+            factors = decode_bytes(factors)
             opts = dict(factors=factors)
             if 'NaN' in colors:
                 opts['nan_color'] = colors['NaN']

holoviews/plotting/bokeh/plot.py

@@ -15,7 +15,7 @@
                     GenericElementPlot, GenericOverlayPlot)
 from ..util import attach_streams
 from .util import (layout_padding, pad_plots, filter_toolboxes, make_axis,
-                   update_shared_sources, empty_plot)
+                   update_shared_sources, empty_plot, decode_bytes)
 
 from bokeh.layouts import gridplot
 from bokeh.plotting.helpers import _known_tools as known_tools
@@ -165,13 +165,15 @@ def _init_datasource(self, data):
         """
         Initializes a data source to be passed into the bokeh glyph.
         """
+        data = {k: decode_bytes(vs) for k, vs in data.items()}
         return ColumnDataSource(data=data)
 
 
     def _update_datasource(self, source, data):
         """
         Update datasource with data for a new frame.
         """
+        data = {k: decode_bytes(vs) for k, vs in data.items()}
         if (self.streaming and self.streaming[0].data is self.current_frame.data
             and self._stream_data):
             stream = self.streaming[0]

holoviews/plotting/bokeh/util.py

@@ -1,4 +1,4 @@
-import inspect, re, time
+import inspect, re, time, sys
 from distutils.version import LooseVersion
 from collections import defaultdict
 import datetime as dt
@@ -66,6 +66,22 @@ def rgba_tuple(rgba):
         return rgba
 
 
+def decode_bytes(array):
+    """
+    Decodes an array, list or tuple of bytestrings to avoid python 3
+    bokeh serialization errors
+    """
+    if (sys.version_info.major == 2 or not len(array) or
+        (isinstance(array, np.ndarray) and array.dtype.kind != 'O')):
+        return array
+    decoded = [v.decode('utf-8') if isinstance(v, bytes) else v for v in array]
+    if isinstance(array, np.ndarray):
+        return np.asarray(decoded)
+    elif isinstance(array, tuple):
+        return tuple(decoded)
+    return decoded
+
+
 def get_cmap(cmap):
     """
     Returns matplotlib cmap generated from bokeh palette or