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Scrapy-Redis-Zhihu/scrapy_redis/connection.py

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+import six
+
+from scrapy.utils.misc import load_object
+
+from . import defaults
+
+
+# Shortcut maps 'setting name' -> 'parmater name'.
+SETTINGS_PARAMS_MAP = {
+    'REDIS_URL': 'url',
+    'REDIS_HOST': 'host',
+    'REDIS_PORT': 'port',
+    'REDIS_ENCODING': 'encoding',
+}
+
+
+def get_redis_from_settings(settings):
+    """Returns a redis client instance from given Scrapy settings object.
+
+    This function uses ``get_client`` to instantiate the client and uses
+    ``defaults.REDIS_PARAMS`` global as defaults values for the parameters. You
+    can override them using the ``REDIS_PARAMS`` setting.
+
+    Parameters
+    ----------
+    settings : Settings
+        A scrapy settings object. See the supported settings below.
+
+    Returns
+    -------
+    server
+        Redis client instance.
+
+    Other Parameters
+    ----------------
+    REDIS_URL : str, optional
+        Server connection URL.
+    REDIS_HOST : str, optional
+        Server host.
+    REDIS_PORT : str, optional
+        Server port.
+    REDIS_ENCODING : str, optional
+        Data encoding.
+    REDIS_PARAMS : dict, optional
+        Additional client parameters.
+
+    """
+    params = defaults.REDIS_PARAMS.copy()
+    params.update(settings.getdict('REDIS_PARAMS'))
+    # XXX: Deprecate REDIS_* settings.
+    for source, dest in SETTINGS_PARAMS_MAP.items():
+        val = settings.get(source)
+        if val:
+            params[dest] = val
+
+    # Allow ``redis_cls`` to be a path to a class.
+    if isinstance(params.get('redis_cls'), six.string_types):
+        params['redis_cls'] = load_object(params['redis_cls'])
+
+    return get_redis(**params)
+
+
+# Backwards compatible alias.
+from_settings = get_redis_from_settings
+
+
+def get_redis(**kwargs):
+    """Returns a redis client instance.
+
+    Parameters
+    ----------
+    redis_cls : class, optional
+        Defaults to ``redis.StrictRedis``.
+    url : str, optional
+        If given, ``redis_cls.from_url`` is used to instantiate the class.
+    **kwargs
+        Extra parameters to be passed to the ``redis_cls`` class.
+
+    Returns
+    -------
+    server
+        Redis client instance.
+
+    """
+    redis_cls = kwargs.pop('redis_cls', defaults.REDIS_CLS)
+    url = kwargs.pop('url', None)
+    if url:
+        return redis_cls.from_url(url, **kwargs)
+    else:
+        return redis_cls(**kwargs)