def __init__(self, cache=None, throttle=0, proxies=None):
"""
Engine constructor.
Kwargs:
cache_type (str): type of cache to use i.e.'instance' or 'engine'.
throttle(int): limits search method to once per 'throttle' arg in seconds (blocking)
proxies (dict): mapping of proxies to use i.e. {"http":"10.10.1.10:3128", "https":"10.10.1.10:1080"}.
Attributes:
cache (QueryCache): instance of QueryCache, instantiated by cache_type arg
last_search (str): datetime of last search
Raises:
CacheException
Usage:
See EngineFactory.
"""
# name of engine
self.name = self.__class__.__name__
# instantiate querycache if necessary
self.cache_type = cache
if cache:
self._cache = QueryCache(self)
# throttle value
self.throttle = throttle
# load proxies
self.proxies = proxies # TODO engine proxies
# datetime of last query
self.last_search = None
self.num_requests = 0
self.num_requests_cached = 0
def __init__(self, cache=None, throttle=0, proxies=None):
"""
Engine constructor.
Kwargs:
cache_type (str): type of cache to use i.e.'instance' or 'engine'.
throttle(int): limits search method to once per 'throttle' arg in seconds (blocking)
proxies (dict): mapping of proxies to use i.e. {"http":"10.10.1.10:3128", "https":"10.10.1.10:1080"}.
Attributes:
cache (QueryCache): instance of QueryCache, instantiated by cache_type arg
last_search (str): datetime of last search
Raises:
CacheException
Usage:
See EngineFactory.
"""
# name of engine
self.name = self.__class__.__name__
# instantiate querycache if necessary
self.cache_type = cache
if cache:
self._cache = QueryCache(self)
# throttle value
self.throttle = throttle
# load proxies
self.proxies = proxies # TODO engine proxies
# datetime of last query
self.last_search = None
self.num_requests = 0
self.num_requests_cached = 0
class Engine(object):
"""
Abstract class representing an ifind search engine.
"""
def __init__(self, cache=None, throttle=0, proxies=None):
"""
Engine constructor.
Kwargs:
cache_type (str): type of cache to use i.e.'instance' or 'engine'.
throttle(int): limits search method to once per 'throttle' arg in seconds (blocking)
proxies (dict): mapping of proxies to use i.e. {"http":"10.10.1.10:3128", "https":"10.10.1.10:1080"}.
Attributes:
cache (QueryCache): instance of QueryCache, instantiated by cache_type arg
last_search (str): datetime of last search
Raises:
CacheException
Usage:
See EngineFactory.
"""
# name of engine
self.name = self.__class__.__name__
# instantiate querycache if necessary
self.cache_type = cache
if cache:
self._cache = QueryCache(self)
# throttle value
self.throttle = throttle
# load proxies
self.proxies = proxies # TODO engine proxies
# datetime of last query
self.last_search = None
self.num_requests = 0
self.num_requests_cached = 0
def search(self, query):
"""
Public search method for an Engine instance, returning the results of a query argument.
Caching handled here, true search implementation deferred to subclass '_search' method.
Args:
query (ifind Query): object encapsulating details of search query.
Returns:
ifind Response: object encapsulating a search request's results.
Raises:
CacheException, InvalidQueryException
Usage:
query = Query('hello world')
engine = EngineFactory('wikipedia')
response = engine.search(query)
"""
# raise exception if search argument isn't an ifind Query object
if not isinstance(query, Query):
raise InvalidQueryException(
'Engine', 'Expected type {}'.format(
"<class 'ifind.search.query.Query'>"))
self.num_requests += 1
# check query in cache and return if there
if self.cache_type:
if query in self._cache:
self.num_requests_cached += 1
return self._cache.get(query)
if self.throttle and self.last_search:
then = datetime.datetime.strptime(self.last_search,
'%a %b %d %H:%M:%S %Y')
now = datetime.datetime.now()
diff = (now - then).seconds
if diff < self.throttle:
#print "waiting {} seconds".format(self.throttle - diff)
time.sleep(self.throttle - diff)
# search and store response
response = self._search(query)
self.last_search = time.asctime()
# cache response if need be
if self.cache_type:
self._cache.store(query, response)
return response
def _search(self, query):
"""
Abstract search method for an Engine instance, to be implemented by subclasses.
Performs a search and retrieves the results as an ifind Response.
Args:
query (ifind Query): object encapsulating details of a search query.
Returns:
ifind Response: object encapsulating a search request's results.
Raises:
See subclasses.
Usage:
Private method.
"""
pass
class Engine(object):
"""
Abstract class representing an ifind search engine.
"""
def __init__(self, cache=None, throttle=0, proxies=None):
"""
Engine constructor.
Kwargs:
cache_type (str): type of cache to use i.e.'instance' or 'engine'.
throttle(int): limits search method to once per 'throttle' arg in seconds (blocking)
proxies (dict): mapping of proxies to use i.e. {"http":"10.10.1.10:3128", "https":"10.10.1.10:1080"}.
Attributes:
cache (QueryCache): instance of QueryCache, instantiated by cache_type arg
last_search (str): datetime of last search
Raises:
CacheException
Usage:
See EngineFactory.
"""
# name of engine
self.name = self.__class__.__name__
# instantiate querycache if necessary
self.cache_type = cache
if cache:
self._cache = QueryCache(self)
# throttle value
self.throttle = throttle
# load proxies
self.proxies = proxies # TODO engine proxies
# datetime of last query
self.last_search = None
self.num_requests = 0
self.num_requests_cached = 0
def search(self, query):
"""
Public search method for an Engine instance, returning the results of a query argument.
Caching handled here, true search implementation deferred to subclass '_search' method.
Args:
query (ifind Query): object encapsulating details of search query.
Returns:
ifind Response: object encapsulating a search request's results.
Raises:
CacheException, InvalidQueryException
Usage:
query = Query('hello world')
engine = EngineFactory('wikipedia')
response = engine.search(query)
"""
# raise exception if search argument isn't an ifind Query object
if not isinstance(query, Query):
raise InvalidQueryException("Engine", "Expected type {}".format("<class 'ifind.search.query.Query'>"))
self.num_requests += 1
# check query in cache and return if there
if self.cache_type:
if query in self._cache:
self.num_requests_cached += 1
return self._cache.get(query)
if self.throttle and self.last_search:
then = datetime.datetime.strptime(self.last_search, "%a %b %d %H:%M:%S %Y")
now = datetime.datetime.now()
diff = (now - then).seconds
if diff < self.throttle:
# print "waiting {} seconds".format(self.throttle - diff)
time.sleep(self.throttle - diff)
# search and store response
response = self._search(query)
self.last_search = time.asctime()
# cache response if need be
if self.cache_type:
self._cache.store(query, response)
return response
def _search(self, query):
"""
Abstract search method for an Engine instance, to be implemented by subclasses.
Performs a search and retrieves the results as an ifind Response.
Args:
query (ifind Query): object encapsulating details of a search query.
Returns:
ifind Response: object encapsulating a search request's results.
Raises:
See subclasses.
Usage:
Private method.
"""
pass
