(output_value, output)
| 213 | |
| 214 | |
| 215 | def fail_callback_output(output_value, output): |
| 216 | valid_children = (str, int, float, type(None), Component, NoUpdate) |
| 217 | valid_props = (str, int, float, type(None), tuple, MutableSequence, NoUpdate) |
| 218 | |
| 219 | def _raise_invalid(bad_val, outer_val, path, index=None, toplevel=False): |
| 220 | bad_type = type(bad_val).__name__ |
| 221 | outer_id = f"(id={outer_val.id:s})" if getattr(outer_val, "id", False) else "" |
| 222 | outer_type = type(outer_val).__name__ |
| 223 | if toplevel: |
| 224 | location = dedent( |
| 225 | """ |
| 226 | The value in question is either the only value returned, |
| 227 | or is in the top level of the returned list, |
| 228 | """ |
| 229 | ) |
| 230 | else: |
| 231 | index_string = "[*]" if index is None else f"[{index:d}]" |
| 232 | location = dedent( |
| 233 | f""" |
| 234 | The value in question is located at |
| 235 | {index_string} {outer_type} {outer_id} |
| 236 | {path}, |
| 237 | """ |
| 238 | ) |
| 239 | |
| 240 | obj = "tree with one value" if not toplevel else "value" |
| 241 | raise exceptions.InvalidCallbackReturnValue( |
| 242 | dedent( |
| 243 | f""" |
| 244 | The callback for `{output!r}` |
| 245 | returned a {obj:s} having type `{bad_type}` |
| 246 | which is not JSON serializable. |
| 247 | |
| 248 | {location} |
| 249 | and has string representation |
| 250 | `{bad_val}` |
| 251 | |
| 252 | In general, Dash properties can only be |
| 253 | dash components, strings, dictionaries, numbers, None, |
| 254 | or lists of those. |
| 255 | """ |
| 256 | ) |
| 257 | ) |
| 258 | |
| 259 | def _valid_child(val): |
| 260 | return isinstance(val, valid_children) |
| 261 | |
| 262 | def _valid_prop(val): |
| 263 | return isinstance(val, valid_props) |
| 264 | |
| 265 | def _can_serialize(val): |
| 266 | if not (_valid_child(val) or _valid_prop(val)): |
| 267 | return False |
| 268 | try: |
| 269 | to_json(val) |
| 270 | except TypeError: |
| 271 | return False |
| 272 | return True |
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