Give a more informative error for JSON not serializable. (#269)

dash/dash.py

@@ -475,6 +475,110 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
+ def _validate_callback_output(self, output_value, output):
+ valid = [str, dict, int, float, type(None), Component]
+
+ def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
+ toplevel=False):
+ outer_id = "(id={:s})".format(outer_val.id) \
+ if getattr(outer_val, 'id', False) else ''
+ outer_type = type(outer_val).__name__
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}` of component `{id:s}`
+ returned a {object:s} having type `{type:s}`
+ which is not JSON serializable.
+
+ {location_header:s}{location:s}
+ and has string representation
+ `{bad_val}`
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(
+ property=output.component_property,
+ id=output.component_id,
+ object='tree with one value' if not toplevel else 'value',
+ type=bad_type,
+ location_header=(
+ 'The value in question is located at'
+ if not toplevel else
+ '''The value in question is either the only value returned,
+ or is in the top level of the returned list,'''
+ ),
+ location=(
+ "\n" +
+ ("[{:d}] {:s} {:s}".format(index, outer_type, outer_id)
+ if index is not None
+ else ('[*] ' + outer_type + ' ' + outer_id))
+ + "\n" + path + "\n"
+ ) if not toplevel else '',
+ bad_val=bad_val).replace(' ', ''))
+
+ def _value_is_valid(val):
+ return (
+ # pylint: disable=unused-variable
+ any([isinstance(val, x) for x in valid]) or
+ type(val).__name__ == 'unicode'
+ )
+
+ def _validate_value(val, index=None):
+ # val is a Component
+ if isinstance(val, Component):
+ for p, j in val.traverse_with_paths():
+ # check each component value in the tree
+ if not _value_is_valid(j):
+ _raise_invalid(
+ bad_val=j,
+ outer_val=val,
+ bad_type=type(j).__name__,
+ path=p,
+ index=index
+ )
+
+ # Children that are not of type Component or
+ # collections.MutableSequence not returned by traverse
+ child = getattr(j, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=p + "\n" + "[*] " + type(child).__name__,
+ index=index
+ )
+
+ # Also check the child of val, as it will not be returned
+ child = getattr(val, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=type(child).__name__,
+ index=index
+ )
+
+ # val is not a Component, but is at the top level of tree
+ else:
+ if not _value_is_valid(val):
+ _raise_invalid(
+ bad_val=val,
+ outer_val=type(val).__name__,
+ bad_type=type(val).__name__,
+ path='',
+ index=index,
+ toplevel=True
+ )
+
+ if isinstance(output_value, list):
+ for i, val in enumerate(output_value):
+ _validate_value(val, index=i)
+ else:
+ _validate_value(output_value)
+
  # TODO - Update nomenclature.
  # "Parents" and "Children" should refer to the DOM tree
  # and not the dependency tree.
@@ -521,9 +625,26 @@ def add_context(*args, **kwargs):
  }
  }
 
+ try:
+ jsonResponse = json.dumps(
+ response,
+ cls=plotly.utils.PlotlyJSONEncoder
+ )
+ except TypeError:
+ self._validate_callback_output(output_value, output)
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}`
+ of component `{id:s}` returned a value
+ which is not JSON serializable.
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(property=output.component_property,
+ id=output.component_id))
+
  return flask.Response(
- json.dumps(response,
- cls=plotly.utils.PlotlyJSONEncoder),
+ jsonResponse,
  mimetype='application/json'
  )
 

dash/development/base_component.py

@@ -151,22 +151,36 @@ def __delitem__(self, id): # pylint: disable=redefined-builtin
 
  def traverse(self):
  """Yield each item in the tree."""
+ for t in self.traverse_with_paths():
+ yield t[1]
+
+ def traverse_with_paths(self):
+ """Yield each item with its path in the tree."""
  children = getattr(self, 'children', None)
+ children_type = type(children).__name__
+ children_id = "(id={:s})".format(children.id) \
+ if getattr(children, 'id', False) else ''
+ children_string = children_type + ' ' + children_id
 
  # children is just a component
  if isinstance(children, Component):
- yield children
- for t in children.traverse():
- yield t
+ yield "[*] " + children_string, children
+ for p, t in children.traverse_with_paths():
+ yield "\n".join(["[*] " + children_string, p]), t
 
  # children is a list of components
  elif isinstance(children, collections.MutableSequence):
- for i in children: # pylint: disable=not-an-iterable
- yield i
+ for idx, i in enumerate(children):
+ list_path = "[{:d}] {:s} {}".format(
+ idx,
+ type(i).__name__,
+ "(id={:s})".format(i.id) if getattr(i, 'id', False) else ''
+ )
+ yield list_path, i
 
  if isinstance(i, Component):
- for t in i.traverse():
- yield t
+ for p, t in i.traverse_with_paths():
+ yield "\n".join([list_path, p]), t
 
  def __iter__(self):
  """Yield IDs in the tree of children."""

dash/exceptions.py

@@ -44,3 +44,7 @@ class CantHaveMultipleOutputs(CallbackException):
 
 class PreventUpdate(CallbackException):
  pass
+
+
+class InvalidCallbackReturnValue(CallbackException):
+ pass

dev-requirements.txt

@@ -12,4 +12,4 @@ six
 plotly>=2.0.8
 requests[security]
 flake8
-pylint
+pylint==1.9.2

dash/dash.py

@@ -475,6 +475,110 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
+ def _validate_callback_output(self, output_value, output):
+ valid = [str, dict, int, float, type(None), Component]
+
+ def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
+ toplevel=False):
+ outer_id = "(id={:s})".format(outer_val.id) \
+ if getattr(outer_val, 'id', False) else ''
+ outer_type = type(outer_val).__name__
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}` of component `{id:s}`
+ returned a {object:s} having type `{type:s}`
+ which is not JSON serializable.
+
+ {location_header:s}{location:s}
+ and has string representation
+ `{bad_val}`
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(
+ property=output.component_property,
+ id=output.component_id,
+ object='tree with one value' if not toplevel else 'value',
+ type=bad_type,
+ location_header=(
+ 'The value in question is located at'
+ if not toplevel else
+ '''The value in question is either the only value returned,
+ or is in the top level of the returned list,'''
+ ),
+ location=(
+ "\n" +
+ ("[{:d}] {:s} {:s}".format(index, outer_type, outer_id)
+ if index is not None
+ else ('[*] ' + outer_type + ' ' + outer_id))
+ + "\n" + path + "\n"
+ ) if not toplevel else '',
+ bad_val=bad_val).replace(' ', ''))
+
+ def _value_is_valid(val):
+ return (
+ # pylint: disable=unused-variable
+ any([isinstance(val, x) for x in valid]) or
+ type(val).__name__ == 'unicode'
+ )
+
+ def _validate_value(val, index=None):
+ # val is a Component
+ if isinstance(val, Component):
+ for p, j in val.traverse_with_paths():
+ # check each component value in the tree
+ if not _value_is_valid(j):
+ _raise_invalid(
+ bad_val=j,
+ outer_val=val,
+ bad_type=type(j).__name__,
+ path=p,
+ index=index
+ )
+
+ # Children that are not of type Component or
+ # collections.MutableSequence not returned by traverse
+ child = getattr(j, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=p + "\n" + "[*] " + type(child).__name__,
+ index=index
+ )
+
+ # Also check the child of val, as it will not be returned
+ child = getattr(val, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=type(child).__name__,
+ index=index
+ )
+
+ # val is not a Component, but is at the top level of tree
+ else:
+ if not _value_is_valid(val):
+ _raise_invalid(
+ bad_val=val,
+ outer_val=type(val).__name__,
+ bad_type=type(val).__name__,
+ path='',
+ index=index,
+ toplevel=True
+ )
+
+ if isinstance(output_value, list):
+ for i, val in enumerate(output_value):
+ _validate_value(val, index=i)
+ else:
+ _validate_value(output_value)
+
  # TODO - Update nomenclature.
  # "Parents" and "Children" should refer to the DOM tree
  # and not the dependency tree.
@@ -521,9 +625,26 @@ def add_context(*args, **kwargs):
  }
  }
 
+ try:
+ jsonResponse = json.dumps(
+ response,
+ cls=plotly.utils.PlotlyJSONEncoder
+ )
+ except TypeError:
+ self._validate_callback_output(output_value, output)
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}`
+ of component `{id:s}` returned a value
+ which is not JSON serializable.
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(property=output.component_property,
+ id=output.component_id))
+
  return flask.Response(
- json.dumps(response,
- cls=plotly.utils.PlotlyJSONEncoder),
+ jsonResponse,
  mimetype='application/json'
  )
 

dash/development/base_component.py

@@ -151,22 +151,36 @@ def __delitem__(self, id): # pylint: disable=redefined-builtin
 
  def traverse(self):
  """Yield each item in the tree."""
+ for t in self.traverse_with_paths():
+ yield t[1]
+
+ def traverse_with_paths(self):
+ """Yield each item with its path in the tree."""
  children = getattr(self, 'children', None)
+ children_type = type(children).__name__
+ children_id = "(id={:s})".format(children.id) \
+ if getattr(children, 'id', False) else ''
+ children_string = children_type + ' ' + children_id
 
  # children is just a component
  if isinstance(children, Component):
- yield children
- for t in children.traverse():
- yield t
+ yield "[*] " + children_string, children
+ for p, t in children.traverse_with_paths():
+ yield "\n".join(["[*] " + children_string, p]), t
 
  # children is a list of components
  elif isinstance(children, collections.MutableSequence):
- for i in children: # pylint: disable=not-an-iterable
- yield i
+ for idx, i in enumerate(children):
+ list_path = "[{:d}] {:s} {}".format(
+ idx,
+ type(i).__name__,
+ "(id={:s})".format(i.id) if getattr(i, 'id', False) else ''
+ )
+ yield list_path, i
 
  if isinstance(i, Component):
- for t in i.traverse():
- yield t
+ for p, t in i.traverse_with_paths():
+ yield "\n".join([list_path, p]), t
 
  def __iter__(self):
  """Yield IDs in the tree of children."""

dash/exceptions.py

@@ -44,3 +44,7 @@ class CantHaveMultipleOutputs(CallbackException):
 
 class PreventUpdate(CallbackException):
  pass
+
+
+class InvalidCallbackReturnValue(CallbackException):
+ pass

dev-requirements.txt

@@ -12,4 +12,4 @@ six
 plotly>=2.0.8
 requests[security]
 flake8
-pylint
+pylint==1.9.2

dash/dash.py

@@ -475,6 +475,110 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
+ def _validate_callback_output(self, output_value, output):
+ valid = [str, dict, int, float, type(None), Component]
+
+ def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
+ toplevel=False):
+ outer_id = "(id={:s})".format(outer_val.id) \
+ if getattr(outer_val, 'id', False) else ''
+ outer_type = type(outer_val).__name__
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}` of component `{id:s}`
+ returned a {object:s} having type `{type:s}`
+ which is not JSON serializable.
+
+ {location_header:s}{location:s}
+ and has string representation
+ `{bad_val}`
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(
+ property=output.component_property,
+ id=output.component_id,
+ object='tree with one value' if not toplevel else 'value',
+ type=bad_type,
+ location_header=(
+ 'The value in question is located at'
+ if not toplevel else
+ '''The value in question is either the only value returned,
+ or is in the top level of the returned list,'''
+ ),
+ location=(
+ "\n" +
+ ("[{:d}] {:s} {:s}".format(index, outer_type, outer_id)
+ if index is not None
+ else ('[*] ' + outer_type + ' ' + outer_id))
+ + "\n" + path + "\n"
+ ) if not toplevel else '',
+ bad_val=bad_val).replace(' ', ''))
+
+ def _value_is_valid(val):
+ return (
+ # pylint: disable=unused-variable
+ any([isinstance(val, x) for x in valid]) or
+ type(val).__name__ == 'unicode'
+ )
+
+ def _validate_value(val, index=None):
+ # val is a Component
+ if isinstance(val, Component):
+ for p, j in val.traverse_with_paths():
+ # check each component value in the tree
+ if not _value_is_valid(j):
+ _raise_invalid(
+ bad_val=j,
+ outer_val=val,
+ bad_type=type(j).__name__,
+ path=p,
+ index=index
+ )
+
+ # Children that are not of type Component or
+ # collections.MutableSequence not returned by traverse
+ child = getattr(j, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=p + "\n" + "[*] " + type(child).__name__,
+ index=index
+ )
+
+ # Also check the child of val, as it will not be returned
+ child = getattr(val, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=type(child).__name__,
+ index=index
+ )
+
+ # val is not a Component, but is at the top level of tree
+ else:
+ if not _value_is_valid(val):
+ _raise_invalid(
+ bad_val=val,
+ outer_val=type(val).__name__,
+ bad_type=type(val).__name__,
+ path='',
+ index=index,
+ toplevel=True
+ )
+
+ if isinstance(output_value, list):
+ for i, val in enumerate(output_value):
+ _validate_value(val, index=i)
+ else:
+ _validate_value(output_value)
+
  # TODO - Update nomenclature.
  # "Parents" and "Children" should refer to the DOM tree
  # and not the dependency tree.
@@ -521,9 +625,26 @@ def add_context(*args, **kwargs):
  }
  }
 
+ try:
+ jsonResponse = json.dumps(
+ response,
+ cls=plotly.utils.PlotlyJSONEncoder
+ )
+ except TypeError:
+ self._validate_callback_output(output_value, output)
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}`
+ of component `{id:s}` returned a value
+ which is not JSON serializable.
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(property=output.component_property,
+ id=output.component_id))
+
  return flask.Response(
- json.dumps(response,
- cls=plotly.utils.PlotlyJSONEncoder),
+ jsonResponse,
  mimetype='application/json'
  )
 

dash/development/base_component.py

@@ -151,22 +151,36 @@ def __delitem__(self, id): # pylint: disable=redefined-builtin
 
  def traverse(self):
  """Yield each item in the tree."""
+ for t in self.traverse_with_paths():
+ yield t[1]
+
+ def traverse_with_paths(self):
+ """Yield each item with its path in the tree."""
  children = getattr(self, 'children', None)
+ children_type = type(children).__name__
+ children_id = "(id={:s})".format(children.id) \
+ if getattr(children, 'id', False) else ''
+ children_string = children_type + ' ' + children_id
 
  # children is just a component
  if isinstance(children, Component):
- yield children
- for t in children.traverse():
- yield t
+ yield "[*] " + children_string, children
+ for p, t in children.traverse_with_paths():
+ yield "\n".join(["[*] " + children_string, p]), t
 
  # children is a list of components
  elif isinstance(children, collections.MutableSequence):
- for i in children: # pylint: disable=not-an-iterable
- yield i
+ for idx, i in enumerate(children):
+ list_path = "[{:d}] {:s} {}".format(
+ idx,
+ type(i).__name__,
+ "(id={:s})".format(i.id) if getattr(i, 'id', False) else ''
+ )
+ yield list_path, i
 
  if isinstance(i, Component):
- for t in i.traverse():
- yield t
+ for p, t in i.traverse_with_paths():
+ yield "\n".join([list_path, p]), t
 
  def __iter__(self):
  """Yield IDs in the tree of children."""

dash/exceptions.py

@@ -44,3 +44,7 @@ class CantHaveMultipleOutputs(CallbackException):
 
 class PreventUpdate(CallbackException):
  pass
+
+
+class InvalidCallbackReturnValue(CallbackException):
+ pass

dev-requirements.txt

@@ -12,4 +12,4 @@ six
 plotly>=2.0.8
 requests[security]
 flake8
-pylint
+pylint==1.9.2

dash/dash.py

@@ -475,6 +475,110 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
+ def _validate_callback_output(self, output_value, output):
+ valid = [str, dict, int, float, type(None), Component]
+
+ def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
+ toplevel=False):
+ outer_id = "(id={:s})".format(outer_val.id) \
+ if getattr(outer_val, 'id', False) else ''
+ outer_type = type(outer_val).__name__
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}` of component `{id:s}`
+ returned a {object:s} having type `{type:s}`
+ which is not JSON serializable.
+
+ {location_header:s}{location:s}
+ and has string representation
+ `{bad_val}`
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(
+ property=output.component_property,
+ id=output.component_id,
+ object='tree with one value' if not toplevel else 'value',
+ type=bad_type,
+ location_header=(
+ 'The value in question is located at'
+ if not toplevel else
+ '''The value in question is either the only value returned,
+ or is in the top level of the returned list,'''
+ ),
+ location=(
+ "\n" +
+ ("[{:d}] {:s} {:s}".format(index, outer_type, outer_id)
+ if index is not None
+ else ('[*] ' + outer_type + ' ' + outer_id))
+ + "\n" + path + "\n"
+ ) if not toplevel else '',
+ bad_val=bad_val).replace(' ', ''))
+
+ def _value_is_valid(val):
+ return (
+ # pylint: disable=unused-variable
+ any([isinstance(val, x) for x in valid]) or
+ type(val).__name__ == 'unicode'
+ )
+
+ def _validate_value(val, index=None):
+ # val is a Component
+ if isinstance(val, Component):
+ for p, j in val.traverse_with_paths():
+ # check each component value in the tree
+ if not _value_is_valid(j):
+ _raise_invalid(
+ bad_val=j,
+ outer_val=val,
+ bad_type=type(j).__name__,
+ path=p,
+ index=index
+ )
+
+ # Children that are not of type Component or
+ # collections.MutableSequence not returned by traverse
+ child = getattr(j, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=p + "\n" + "[*] " + type(child).__name__,
+ index=index
+ )
+
+ # Also check the child of val, as it will not be returned
+ child = getattr(val, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=type(child).__name__,
+ index=index
+ )
+
+ # val is not a Component, but is at the top level of tree
+ else:
+ if not _value_is_valid(val):
+ _raise_invalid(
+ bad_val=val,
+ outer_val=type(val).__name__,
+ bad_type=type(val).__name__,
+ path='',
+ index=index,
+ toplevel=True
+ )
+
+ if isinstance(output_value, list):
+ for i, val in enumerate(output_value):
+ _validate_value(val, index=i)
+ else:
+ _validate_value(output_value)
+
  # TODO - Update nomenclature.
  # "Parents" and "Children" should refer to the DOM tree
  # and not the dependency tree.
@@ -521,9 +625,26 @@ def add_context(*args, **kwargs):
  }
  }
 
+ try:
+ jsonResponse = json.dumps(
+ response,
+ cls=plotly.utils.PlotlyJSONEncoder
+ )
+ except TypeError:
+ self._validate_callback_output(output_value, output)
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}`
+ of component `{id:s}` returned a value
+ which is not JSON serializable.
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(property=output.component_property,
+ id=output.component_id))
+
  return flask.Response(
- json.dumps(response,
- cls=plotly.utils.PlotlyJSONEncoder),
+ jsonResponse,
  mimetype='application/json'
  )
 

dash/development/base_component.py

@@ -151,22 +151,36 @@ def __delitem__(self, id): # pylint: disable=redefined-builtin
 
  def traverse(self):
  """Yield each item in the tree."""
+ for t in self.traverse_with_paths():
+ yield t[1]
+
+ def traverse_with_paths(self):
+ """Yield each item with its path in the tree."""
  children = getattr(self, 'children', None)
+ children_type = type(children).__name__
+ children_id = "(id={:s})".format(children.id) \
+ if getattr(children, 'id', False) else ''
+ children_string = children_type + ' ' + children_id
 
  # children is just a component
  if isinstance(children, Component):
- yield children
- for t in children.traverse():
- yield t
+ yield "[*] " + children_string, children
+ for p, t in children.traverse_with_paths():
+ yield "\n".join(["[*] " + children_string, p]), t
 
  # children is a list of components
  elif isinstance(children, collections.MutableSequence):
- for i in children: # pylint: disable=not-an-iterable
- yield i
+ for idx, i in enumerate(children):
+ list_path = "[{:d}] {:s} {}".format(
+ idx,
+ type(i).__name__,
+ "(id={:s})".format(i.id) if getattr(i, 'id', False) else ''
+ )
+ yield list_path, i
 
  if isinstance(i, Component):
- for t in i.traverse():
- yield t
+ for p, t in i.traverse_with_paths():
+ yield "\n".join([list_path, p]), t
 
  def __iter__(self):
  """Yield IDs in the tree of children."""

dash/exceptions.py

@@ -44,3 +44,7 @@ class CantHaveMultipleOutputs(CallbackException):
 
 class PreventUpdate(CallbackException):
  pass
+
+
+class InvalidCallbackReturnValue(CallbackException):
+ pass

dev-requirements.txt

@@ -12,4 +12,4 @@ six
 plotly>=2.0.8
 requests[security]
 flake8
-pylint
+pylint==1.9.2

dash/dash.py

@@ -475,6 +475,110 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
+ def _validate_callback_output(self, output_value, output):
+ valid = [str, dict, int, float, type(None), Component]
+
+ def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
+ toplevel=False):
+ outer_id = "(id={:s})".format(outer_val.id) \
+ if getattr(outer_val, 'id', False) else ''
+ outer_type = type(outer_val).__name__
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}` of component `{id:s}`
+ returned a {object:s} having type `{type:s}`
+ which is not JSON serializable.
+
+ {location_header:s}{location:s}
+ and has string representation
+ `{bad_val}`
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(
+ property=output.component_property,
+ id=output.component_id,
+ object='tree with one value' if not toplevel else 'value',
+ type=bad_type,
+ location_header=(
+ 'The value in question is located at'
+ if not toplevel else
+ '''The value in question is either the only value returned,
+ or is in the top level of the returned list,'''
+ ),
+ location=(
+ "\n" +
+ ("[{:d}] {:s} {:s}".format(index, outer_type, outer_id)
+ if index is not None
+ else ('[*] ' + outer_type + ' ' + outer_id))
+ + "\n" + path + "\n"
+ ) if not toplevel else '',
+ bad_val=bad_val).replace(' ', ''))
+
+ def _value_is_valid(val):
+ return (
+ # pylint: disable=unused-variable
+ any([isinstance(val, x) for x in valid]) or
+ type(val).__name__ == 'unicode'
+ )
+
+ def _validate_value(val, index=None):
+ # val is a Component
+ if isinstance(val, Component):
+ for p, j in val.traverse_with_paths():
+ # check each component value in the tree
+ if not _value_is_valid(j):
+ _raise_invalid(
+ bad_val=j,
+ outer_val=val,
+ bad_type=type(j).__name__,
+ path=p,
+ index=index
+ )
+
+ # Children that are not of type Component or
+ # collections.MutableSequence not returned by traverse
+ child = getattr(j, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=p + "\n" + "[*] " + type(child).__name__,
+ index=index
+ )
+
+ # Also check the child of val, as it will not be returned
+ child = getattr(val, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=type(child).__name__,
+ index=index
+ )
+
+ # val is not a Component, but is at the top level of tree
+ else:
+ if not _value_is_valid(val):
+ _raise_invalid(
+ bad_val=val,
+ outer_val=type(val).__name__,
+ bad_type=type(val).__name__,
+ path='',
+ index=index,
+ toplevel=True
+ )
+
+ if isinstance(output_value, list):
+ for i, val in enumerate(output_value):
+ _validate_value(val, index=i)
+ else:
+ _validate_value(output_value)
+
  # TODO - Update nomenclature.
  # "Parents" and "Children" should refer to the DOM tree
  # and not the dependency tree.
@@ -521,9 +625,26 @@ def add_context(*args, **kwargs):
  }
  }
 
+ try:
+ jsonResponse = json.dumps(
+ response,
+ cls=plotly.utils.PlotlyJSONEncoder
+ )
+ except TypeError:
+ self._validate_callback_output(output_value, output)
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}`
+ of component `{id:s}` returned a value
+ which is not JSON serializable.
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(property=output.component_property,
+ id=output.component_id))
+
  return flask.Response(
- json.dumps(response,
- cls=plotly.utils.PlotlyJSONEncoder),
+ jsonResponse,
  mimetype='application/json'
  )
 

dash/development/base_component.py

@@ -151,22 +151,36 @@ def __delitem__(self, id): # pylint: disable=redefined-builtin
 
  def traverse(self):
  """Yield each item in the tree."""
+ for t in self.traverse_with_paths():
+ yield t[1]
+
+ def traverse_with_paths(self):
+ """Yield each item with its path in the tree."""
  children = getattr(self, 'children', None)
+ children_type = type(children).__name__
+ children_id = "(id={:s})".format(children.id) \
+ if getattr(children, 'id', False) else ''
+ children_string = children_type + ' ' + children_id
 
  # children is just a component
  if isinstance(children, Component):
- yield children
- for t in children.traverse():
- yield t
+ yield "[*] " + children_string, children
+ for p, t in children.traverse_with_paths():
+ yield "\n".join(["[*] " + children_string, p]), t
 
  # children is a list of components
  elif isinstance(children, collections.MutableSequence):
- for i in children: # pylint: disable=not-an-iterable
- yield i
+ for idx, i in enumerate(children):
+ list_path = "[{:d}] {:s} {}".format(
+ idx,
+ type(i).__name__,
+ "(id={:s})".format(i.id) if getattr(i, 'id', False) else ''
+ )
+ yield list_path, i
 
  if isinstance(i, Component):
- for t in i.traverse():
- yield t
+ for p, t in i.traverse_with_paths():
+ yield "\n".join([list_path, p]), t
 
  def __iter__(self):
  """Yield IDs in the tree of children."""

dash/exceptions.py

@@ -44,3 +44,7 @@ class CantHaveMultipleOutputs(CallbackException):
 
 class PreventUpdate(CallbackException):
  pass
+
+
+class InvalidCallbackReturnValue(CallbackException):
+ pass

dev-requirements.txt

@@ -12,4 +12,4 @@ six
 plotly>=2.0.8
 requests[security]
 flake8
-pylint
+pylint==1.9.2

dash/dash.py

@@ -475,6 +475,110 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
+ def _validate_callback_output(self, output_value, output):
+ valid = [str, dict, int, float, type(None), Component]
+
+ def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
+ toplevel=False):
+ outer_id = "(id={:s})".format(outer_val.id) \
+ if getattr(outer_val, 'id', False) else ''
+ outer_type = type(outer_val).__name__
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}` of component `{id:s}`
+ returned a {object:s} having type `{type:s}`
+ which is not JSON serializable.
+
+ {location_header:s}{location:s}
+ and has string representation
+ `{bad_val}`
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(
+ property=output.component_property,
+ id=output.component_id,
+ object='tree with one value' if not toplevel else 'value',
+ type=bad_type,
+ location_header=(
+ 'The value in question is located at'
+ if not toplevel else
+ '''The value in question is either the only value returned,
+ or is in the top level of the returned list,'''
+ ),
+ location=(
+ "\n" +
+ ("[{:d}] {:s} {:s}".format(index, outer_type, outer_id)
+ if index is not None
+ else ('[*] ' + outer_type + ' ' + outer_id))
+ + "\n" + path + "\n"
+ ) if not toplevel else '',
+ bad_val=bad_val).replace(' ', ''))
+
+ def _value_is_valid(val):
+ return (
+ # pylint: disable=unused-variable
+ any([isinstance(val, x) for x in valid]) or
+ type(val).__name__ == 'unicode'
+ )
+
+ def _validate_value(val, index=None):
+ # val is a Component
+ if isinstance(val, Component):
+ for p, j in val.traverse_with_paths():
+ # check each component value in the tree
+ if not _value_is_valid(j):
+ _raise_invalid(
+ bad_val=j,
+ outer_val=val,
+ bad_type=type(j).__name__,
+ path=p,
+ index=index
+ )
+
+ # Children that are not of type Component or
+ # collections.MutableSequence not returned by traverse
+ child = getattr(j, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=p + "\n" + "[*] " + type(child).__name__,
+ index=index
+ )
+
+ # Also check the child of val, as it will not be returned
+ child = getattr(val, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=type(child).__name__,
+ index=index
+ )
+
+ # val is not a Component, but is at the top level of tree
+ else:
+ if not _value_is_valid(val):
+ _raise_invalid(
+ bad_val=val,
+ outer_val=type(val).__name__,
+ bad_type=type(val).__name__,
+ path='',
+ index=index,
+ toplevel=True
+ )
+
+ if isinstance(output_value, list):
+ for i, val in enumerate(output_value):
+ _validate_value(val, index=i)
+ else:
+ _validate_value(output_value)
+
  # TODO - Update nomenclature.
  # "Parents" and "Children" should refer to the DOM tree
  # and not the dependency tree.
@@ -521,9 +625,26 @@ def add_context(*args, **kwargs):
  }
  }
 
+ try:
+ jsonResponse = json.dumps(
+ response,
+ cls=plotly.utils.PlotlyJSONEncoder
+ )
+ except TypeError:
+ self._validate_callback_output(output_value, output)
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}`
+ of component `{id:s}` returned a value
+ which is not JSON serializable.
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(property=output.component_property,
+ id=output.component_id))
+
  return flask.Response(
- json.dumps(response,
- cls=plotly.utils.PlotlyJSONEncoder),
+ jsonResponse,
  mimetype='application/json'
  )
 

dash/development/base_component.py

@@ -151,22 +151,36 @@ def __delitem__(self, id): # pylint: disable=redefined-builtin
 
  def traverse(self):
  """Yield each item in the tree."""
+ for t in self.traverse_with_paths():
+ yield t[1]
+
+ def traverse_with_paths(self):
+ """Yield each item with its path in the tree."""
  children = getattr(self, 'children', None)
+ children_type = type(children).__name__
+ children_id = "(id={:s})".format(children.id) \
+ if getattr(children, 'id', False) else ''
+ children_string = children_type + ' ' + children_id
 
  # children is just a component
  if isinstance(children, Component):
- yield children
- for t in children.traverse():
- yield t
+ yield "[*] " + children_string, children
+ for p, t in children.traverse_with_paths():
+ yield "\n".join(["[*] " + children_string, p]), t
 
  # children is a list of components
  elif isinstance(children, collections.MutableSequence):
- for i in children: # pylint: disable=not-an-iterable
- yield i
+ for idx, i in enumerate(children):
+ list_path = "[{:d}] {:s} {}".format(
+ idx,
+ type(i).__name__,
+ "(id={:s})".format(i.id) if getattr(i, 'id', False) else ''
+ )
+ yield list_path, i
 
  if isinstance(i, Component):
- for t in i.traverse():
- yield t
+ for p, t in i.traverse_with_paths():
+ yield "\n".join([list_path, p]), t
 
  def __iter__(self):
  """Yield IDs in the tree of children."""

dash/exceptions.py

@@ -44,3 +44,7 @@ class CantHaveMultipleOutputs(CallbackException):
 
 class PreventUpdate(CallbackException):
  pass
+
+
+class InvalidCallbackReturnValue(CallbackException):
+ pass

dev-requirements.txt

@@ -12,4 +12,4 @@ six
 plotly>=2.0.8
 requests[security]
 flake8
-pylint
+pylint==1.9.2

dash/dash.py

@@ -475,6 +475,110 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
+ def _validate_callback_output(self, output_value, output):
+ valid = [str, dict, int, float, type(None), Component]
+
+ def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
+ toplevel=False):
+ outer_id = "(id={:s})".format(outer_val.id) \
+ if getattr(outer_val, 'id', False) else ''
+ outer_type = type(outer_val).__name__
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}` of component `{id:s}`
+ returned a {object:s} having type `{type:s}`
+ which is not JSON serializable.
+
+ {location_header:s}{location:s}
+ and has string representation
+ `{bad_val}`
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(
+ property=output.component_property,
+ id=output.component_id,
+ object='tree with one value' if not toplevel else 'value',
+ type=bad_type,
+ location_header=(
+ 'The value in question is located at'
+ if not toplevel else
+ '''The value in question is either the only value returned,
+ or is in the top level of the returned list,'''
+ ),
+ location=(
+ "\n" +
+ ("[{:d}] {:s} {:s}".format(index, outer_type, outer_id)
+ if index is not None
+ else ('[*] ' + outer_type + ' ' + outer_id))
+ + "\n" + path + "\n"
+ ) if not toplevel else '',
+ bad_val=bad_val).replace(' ', ''))
+
+ def _value_is_valid(val):
+ return (
+ # pylint: disable=unused-variable
+ any([isinstance(val, x) for x in valid]) or
+ type(val).__name__ == 'unicode'
+ )
+
+ def _validate_value(val, index=None):
+ # val is a Component
+ if isinstance(val, Component):
+ for p, j in val.traverse_with_paths():
+ # check each component value in the tree
+ if not _value_is_valid(j):
+ _raise_invalid(
+ bad_val=j,
+ outer_val=val,
+ bad_type=type(j).__name__,
+ path=p,
+ index=index
+ )
+
+ # Children that are not of type Component or
+ # collections.MutableSequence not returned by traverse
+ child = getattr(j, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=p + "\n" + "[*] " + type(child).__name__,
+ index=index
+ )
+
+ # Also check the child of val, as it will not be returned
+ child = getattr(val, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=type(child).__name__,
+ index=index
+ )
+
+ # val is not a Component, but is at the top level of tree
+ else:
+ if not _value_is_valid(val):
+ _raise_invalid(
+ bad_val=val,
+ outer_val=type(val).__name__,
+ bad_type=type(val).__name__,
+ path='',
+ index=index,
+ toplevel=True
+ )
+
+ if isinstance(output_value, list):
+ for i, val in enumerate(output_value):
+ _validate_value(val, index=i)
+ else:
+ _validate_value(output_value)
+
  # TODO - Update nomenclature.
  # "Parents" and "Children" should refer to the DOM tree
  # and not the dependency tree.
@@ -521,9 +625,26 @@ def add_context(*args, **kwargs):
  }
  }
 
+ try:
+ jsonResponse = json.dumps(
+ response,
+ cls=plotly.utils.PlotlyJSONEncoder
+ )
+ except TypeError:
+ self._validate_callback_output(output_value, output)
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}`
+ of component `{id:s}` returned a value
+ which is not JSON serializable.
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(property=output.component_property,
+ id=output.component_id))
+
  return flask.Response(
- json.dumps(response,
- cls=plotly.utils.PlotlyJSONEncoder),
+ jsonResponse,
  mimetype='application/json'
  )
 

dash/development/base_component.py

@@ -151,22 +151,36 @@ def __delitem__(self, id): # pylint: disable=redefined-builtin
 
  def traverse(self):
  """Yield each item in the tree."""
+ for t in self.traverse_with_paths():
+ yield t[1]
+
+ def traverse_with_paths(self):
+ """Yield each item with its path in the tree."""
  children = getattr(self, 'children', None)
+ children_type = type(children).__name__
+ children_id = "(id={:s})".format(children.id) \
+ if getattr(children, 'id', False) else ''
+ children_string = children_type + ' ' + children_id
 
  # children is just a component
  if isinstance(children, Component):
- yield children
- for t in children.traverse():
- yield t
+ yield "[*] " + children_string, children
+ for p, t in children.traverse_with_paths():
+ yield "\n".join(["[*] " + children_string, p]), t
 
  # children is a list of components
  elif isinstance(children, collections.MutableSequence):
- for i in children: # pylint: disable=not-an-iterable
- yield i
+ for idx, i in enumerate(children):
+ list_path = "[{:d}] {:s} {}".format(
+ idx,
+ type(i).__name__,
+ "(id={:s})".format(i.id) if getattr(i, 'id', False) else ''
+ )
+ yield list_path, i
 
  if isinstance(i, Component):
- for t in i.traverse():
- yield t
+ for p, t in i.traverse_with_paths():
+ yield "\n".join([list_path, p]), t
 
  def __iter__(self):
  """Yield IDs in the tree of children."""

dash/exceptions.py

@@ -44,3 +44,7 @@ class CantHaveMultipleOutputs(CallbackException):
 
 class PreventUpdate(CallbackException):
  pass
+
+
+class InvalidCallbackReturnValue(CallbackException):
+ pass

dev-requirements.txt

@@ -12,4 +12,4 @@ six
 plotly>=2.0.8
 requests[security]
 flake8
-pylint
+pylint==1.9.2

dash/dash.py

@@ -475,6 +475,110 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
+ def _validate_callback_output(self, output_value, output):
+ valid = [str, dict, int, float, type(None), Component]
+
+ def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
+ toplevel=False):
+ outer_id = "(id={:s})".format(outer_val.id) \
+ if getattr(outer_val, 'id', False) else ''
+ outer_type = type(outer_val).__name__
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}` of component `{id:s}`
+ returned a {object:s} having type `{type:s}`
+ which is not JSON serializable.
+
+ {location_header:s}{location:s}
+ and has string representation
+ `{bad_val}`
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(
+ property=output.component_property,
+ id=output.component_id,
+ object='tree with one value' if not toplevel else 'value',
+ type=bad_type,
+ location_header=(
+ 'The value in question is located at'
+ if not toplevel else
+ '''The value in question is either the only value returned,
+ or is in the top level of the returned list,'''
+ ),
+ location=(
+ "\n" +
+ ("[{:d}] {:s} {:s}".format(index, outer_type, outer_id)
+ if index is not None
+ else ('[*] ' + outer_type + ' ' + outer_id))
+ + "\n" + path + "\n"
+ ) if not toplevel else '',
+ bad_val=bad_val).replace(' ', ''))
+
+ def _value_is_valid(val):
+ return (
+ # pylint: disable=unused-variable
+ any([isinstance(val, x) for x in valid]) or
+ type(val).__name__ == 'unicode'
+ )
+
+ def _validate_value(val, index=None):
+ # val is a Component
+ if isinstance(val, Component):
+ for p, j in val.traverse_with_paths():
+ # check each component value in the tree
+ if not _value_is_valid(j):
+ _raise_invalid(
+ bad_val=j,
+ outer_val=val,
+ bad_type=type(j).__name__,
+ path=p,
+ index=index
+ )
+
+ # Children that are not of type Component or
+ # collections.MutableSequence not returned by traverse
+ child = getattr(j, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=p + "\n" + "[*] " + type(child).__name__,
+ index=index
+ )
+
+ # Also check the child of val, as it will not be returned
+ child = getattr(val, 'children', None)
+ if not isinstance(child, collections.MutableSequence):
+ if child and not _value_is_valid(child):
+ _raise_invalid(
+ bad_val=child,
+ outer_val=val,
+ bad_type=type(child).__name__,
+ path=type(child).__name__,
+ index=index
+ )
+
+ # val is not a Component, but is at the top level of tree
+ else:
+ if not _value_is_valid(val):
+ _raise_invalid(
+ bad_val=val,
+ outer_val=type(val).__name__,
+ bad_type=type(val).__name__,
+ path='',
+ index=index,
+ toplevel=True
+ )
+
+ if isinstance(output_value, list):
+ for i, val in enumerate(output_value):
+ _validate_value(val, index=i)
+ else:
+ _validate_value(output_value)
+
  # TODO - Update nomenclature.
  # "Parents" and "Children" should refer to the DOM tree
  # and not the dependency tree.
@@ -521,9 +625,26 @@ def add_context(*args, **kwargs):
  }
  }
 
+ try:
+ jsonResponse = json.dumps(
+ response,
+ cls=plotly.utils.PlotlyJSONEncoder
+ )
+ except TypeError:
+ self._validate_callback_output(output_value, output)
+ raise exceptions.InvalidCallbackReturnValue('''
+ The callback for property `{property:s}`
+ of component `{id:s}` returned a value
+ which is not JSON serializable.
+
+ In general, Dash properties can only be
+ dash components, strings, dictionaries, numbers, None,
+ or lists of those.
+ '''.format(property=output.component_property,
+ id=output.component_id))
+
  return flask.Response(
- json.dumps(response,
- cls=plotly.utils.PlotlyJSONEncoder),
+ jsonResponse,
  mimetype='application/json'
  )
 

dash/development/base_component.py

@@ -151,22 +151,36 @@ def __delitem__(self, id): # pylint: disable=redefined-builtin
 
  def traverse(self):
  """Yield each item in the tree."""
+ for t in self.traverse_with_paths():
+ yield t[1]
+
+ def traverse_with_paths(self):
+ """Yield each item with its path in the tree."""
  children = getattr(self, 'children', None)
+ children_type = type(children).__name__
+ children_id = "(id={:s})".format(children.id) \
+ if getattr(children, 'id', False) else ''
+ children_string = children_type + ' ' + children_id
 
  # children is just a component
  if isinstance(children, Component):
- yield children
- for t in children.traverse():
- yield t
+ yield "[*] " + children_string, children
+ for p, t in children.traverse_with_paths():
+ yield "\n".join(["[*] " + children_string, p]), t
 
  # children is a list of components
  elif isinstance(children, collections.MutableSequence):
- for i in children: # pylint: disable=not-an-iterable
- yield i
+ for idx, i in enumerate(children):
+ list_path = "[{:d}] {:s} {}".format(
+ idx,
+ type(i).__name__,
+ "(id={:s})".format(i.id) if getattr(i, 'id', False) else ''
+ )
+ yield list_path, i
 
  if isinstance(i, Component):
- for t in i.traverse():
- yield t
+ for p, t in i.traverse_with_paths():
+ yield "\n".join([list_path, p]), t
 
  def __iter__(self):
  """Yield IDs in the tree of children."""

dash/exceptions.py

@@ -44,3 +44,7 @@ class CantHaveMultipleOutputs(CallbackException):
 
 class PreventUpdate(CallbackException):
  pass
+
+
+class InvalidCallbackReturnValue(CallbackException):
+ pass

dev-requirements.txt

@@ -12,4 +12,4 @@ six
 plotly>=2.0.8
 requests[security]
 flake8
-pylint
+pylint==1.9.2