from abc import ABC, abstractmethod
from typing import Any, Dict, Union
StatNum = Union[int, float]
[docs]class StatCollector(ABC):
"""Base class for web-poet to implement the storing of data written through
:class:`~web_poet.page_inputs.stats.Stats`."""
[docs] @abstractmethod
def set(self, key: str, value: Any) -> None:
"""Set the value of stat *key* to *value*."""
[docs] @abstractmethod
def inc(self, key: str, value: StatNum = 1) -> None:
"""Increment the value of stat *key* by *value*, or set it to *value*
if *key* has no value."""
[docs]class DummyStatCollector(StatCollector):
""":class:`~web_poet.page_inputs.stats.StatCollector` implementation that
does not persist stats. It is used when running automatic tests, where stat
storage is not necessary."""
def __init__(self):
self._stats: Dict[str, Any] = {}
[docs] def set(self, key: str, value: Any) -> None: # noqa: D102
self._stats[key] = value
[docs] def inc(self, key: str, value: StatNum = 1) -> None: # noqa: D102
if key in self._stats:
assert isinstance(self._stats[key], (int, float))
self._stats[key] += value
else:
self._stats[key] = value
[docs]class Stats:
"""Page input class to write key-value data pairs during parsing that you
can inspect later. See :ref:`stats`.
Stats can be set to a fixed value or, if numeric, incremented.
Stats are write-only.
Storage and read access of stats depends on the web-poet framework that you
are using. Check the documentation of your web-poet framework to find out
if it supports stats, and if so, how to read stored stats.
"""
def __init__(self, stat_collector=None):
self._stats = stat_collector or DummyStatCollector()
[docs] def set(self, key: str, value: Any) -> None:
"""Set the value of stat *key* to *value*."""
self._stats.set(key, value)
[docs] def inc(self, key: str, value: StatNum = 1) -> None:
"""Increment the value of stat *key* by *value*, or set it to *value*
if *key* has no value."""
self._stats.inc(key, value)