Split up into modules

socialmediascraper/base.py

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+import abc
+import logging
+import requests
+
+
+logger = logging.getLogger(__name__)
+
+
+class Item:
+	'''An abstract base class for an item returned by the scraper's get_items generator.
+
+	An item can really be anything. The string representation should be useful for the CLI output (e.g. a direct URL for the item).'''
+
+	@abc.abstractmethod
+	def __str__(self):
+		pass
+
+
+class URLItem(Item):
+	'''A generic item which only holds a URL string.'''
+
+	def __init__(self, url):
+		self._url = url
+
+	@property
+	def url(self):
+		return self._url
+
+	def __str__(self):
+		return self._url
+
+
+class ScraperException(Exception):
+	pass
+
+
+class Scraper:
+	'''An abstract base class for a scraper.'''
+
+	name = None
+
+	def __init__(self, retries = 3):
+		self._retries = retries
+
+	@abc.abstractmethod
+	def get_items(self):
+		'''Iterator yielding Items.'''
+		pass
+
+	def _get(self, url, params = None, headers = None, responseOkCallback = None):
+		for attempt in range(self._retries + 1):
+			logger.info(f'Retrieving {url}')
+			logger.debug(f'... with parameters: {params!r}')
+			logger.debug(f'... with headers: {headers!r}')
+			try:
+				r = requests.get(url, params = params, headers = headers)
+				if responseOkCallback is None or responseOkCallback(r):
+					logger.debug(f'{r.request.url} retrieved successfully')
+					return r
+			except requests.exceptions.RequestException as exc:
+				logger.error(f'Error retrieving {url}: {exc!r}')
+		else:
+			msg = f'{self._retries + 1} requests to {url} failed, giving up.'
+			logger.fatal(msg)
+			raise ScraperException(msg)
+		raise RuntimeError('Reached unreachable code')
+
+	@classmethod
+	@abc.abstractmethod
+	def setup_parser(cls, subparser):
+		pass
+
+	@classmethod
+	@abc.abstractmethod
+	def from_args(cls, args):
+		pass