new crawler with cache control and error handling

2 files changed, 210 insertions, 8 deletions

diff --git a/pyaggr3g470r/lib/crawler.py b/pyaggr3g470r/lib/crawler.py
index 1d7fca71..6697e4c3 100644
--- a/pyaggr3g470r/lib/crawler.py
+++ b/pyaggr3g470r/lib/crawler.py
@@ -1,11 +1,199 @@
+import conf
+import json
+import logging
+import requests
 import feedparser
-import dateutil.parser.parse
+import dateutil.parser
+from datetime import datetime
+from concurrent.futures import ThreadPoolExecutor
+from requests_futures.sessions import FuturesSession
+from pyaggr3g470r.lib.utils import default_handler
 
+logger = logging.getLogger(__name__)
 
-def get_feed_content(feed):
-    etag = feed.get('etag', None)
-    last_modified = None
-    if feed.get('last_modified'):
-        last_modified = dateutil.parser.parse(feed['last_modified'])\
-                                    .strftime('%a, %d %b %Y %H:%M:%S %Z')
-    return feedparser.parse(feed['link'], etag=etag, modified=last_modified)
+
+def extract_id(entry, keys=[('link', 'link'),
+                            ('published', 'retrieved_date'),
+                            ('updated', 'retrieved_date')], force_id=False):
+    entry_id = entry.get('entry_id') or entry.get('id')
+    if entry_id:
+        return {'entry_id': entry_id}
+    if not entry_id and force_id:
+        entry_id = hash("".join(entry[entry_key] for _, entry_key in keys
+                                if entry_key in entry))
+    else:
+        ids = {}
+        for entry_key, pyagg_key in keys:
+            if entry_key in entry and pyagg_key not in ids:
+                ids[pyagg_key] = entry[entry_key]
+                if 'date' in pyagg_key:
+                    ids[pyagg_key] = dateutil.parser.parse(ids[pyagg_key])\
+                                                    .isoformat()
+        return ids
+
+
+class AbstractCrawler:
+    __session__ = None
+
+    def __init__(self, auth):
+        self.auth = auth
+        self.session = self.get_session()
+        self.url = conf.PLATFORM_URL
+
+    @classmethod
+    def get_session(cls):
+        if cls.__session__ is None:
+            cls.__session__ = FuturesSession(
+                    executor=ThreadPoolExecutor(max_workers=conf.NB_WORKER))
+            cls.__session__.verify = False
+        return cls.__session__
+
+    def query_pyagg(self, method, urn, data=None):
+        if data is None:
+            data = {}
+        method = getattr(self.session, method)
+        return method("%sapi/v1.0/%s" % (self.url, urn),
+                      auth=self.auth, data=json.dumps(data,
+                                                      default=default_handler),
+                      headers={'Content-Type': 'application/json'})
+
+
+class PyAggUpdater(AbstractCrawler):
+
+    def __init__(self, feed, entries, headers, auth):
+        self.feed = feed
+        self.entries = entries
+        self.headers = headers
+        super(PyAggUpdater, self).__init__(auth)
+
+    def to_article(self, entry):
+        date = datetime.now()
+
+        for date_key in ('published', 'updated'):
+            if entry.get(date_key):
+                try:
+                    date = dateutil.parser.parse(entry[date_key])
+                except Exception:
+                    pass
+                else:
+                    break
+        content = ''
+        if entry.get('content'):
+            content = entry['content'][0]['value']
+        elif entry.get('summary'):
+            content = entry['summary']
+
+        return {'feed_id': self.feed['id'],
+                'entry_id': extract_id(entry).get('entry_id', None),
+                'link': entry.get('link', self.feed['site_link']),
+                'title': entry.get('title', 'No title'),
+                'readed': False, 'like': False,
+                'content': content,
+                'retrieved_date': date.isoformat(),
+                'date': date.isoformat()}
+
+    def callback(self, response):
+        try:
+            results = response.result().json()
+        except Exception:
+            logger.exception('something went wront with feed %r %r %r %r',
+                             self.feed, self.headers, response.result(),
+                             getattr(response.result(), 'data', None))
+            return
+        logger.debug('%r %r - %d entries were not matched',
+                     self.feed['id'], self.feed['title'], len(results))
+        for id_to_create in results:
+            entry = self.entries[tuple(sorted(id_to_create.items()))]
+            try:
+                logger.debug('creating %r - %r', entry['title'], id_to_create)
+                self.to_article(entry)
+            except:
+                logger.exception('%r %r %r something failed when parsing %r',
+                                 self.feed['title'], self.feed['id'],
+                                 self.feed['link'], entry)
+            self.query_pyagg('post', 'article', self.to_article(entry))
+
+        now = datetime.now()
+        logger.debug('%r %r - updating feed etag %r last_mod %r',
+                     self.feed['id'], self.feed['title'],
+                     self.headers.get('etag'), now)
+
+        self.query_pyagg('put', 'feed/%d' % self.feed['id'], {'error_count': 0,
+                     'etag': self.headers.get('etag', ''),
+                     'last_modified': self.headers.get('last-modified', '')})
+
+
+class FeedCrawler(AbstractCrawler):
+
+    def __init__(self, feed, auth):
+        self.feed = feed
+        super(FeedCrawler, self).__init__(auth)
+
+    def callback(self, response):
+        try:
+            response = response.result()
+            response.raise_for_status()
+        except Exception as error:
+            error_count = self.feed['error_count'] + 1
+            logger.warn('%r %r - an error occured while fetching feed; bumping'
+                        ' error count to %r', self.feed['title'],
+                        self.feed['id'], error_count)
+            self.query_pyagg('put', 'feed/%d' % self.feed['id'],
+                             {'error_count': error_count,
+                              'last_error': str(error)})
+            return
+
+        if response.status_code == 304:
+            logger.debug("%r %r - feed responded with 304",
+                         self.feed['id'], self.feed['title'])
+            return
+        if self.feed['etag'] and response.headers.get('etag') \
+                and response.headers.get('etag') == self.feed['etag']:
+            logger.debug("%r %r - feed responded with same etag (%d) %r",
+                         self.feed['id'], self.feed['title'],
+                         response.status_code, self.feed['link'])
+            return
+        ids, entries = [], {}
+        parsed_response = feedparser.parse(response.text)
+        for entry in parsed_response['entries']:
+            entries[tuple(sorted(extract_id(entry).items()))] = entry
+            ids.append(extract_id(entry))
+        logger.debug('%r %r - found %d entries %r',
+                     self.feed['id'], self.feed['title'], len(ids), ids)
+        future = self.query_pyagg('get', 'articles/challenge', {'ids': ids})
+        updater = PyAggUpdater(self.feed, entries, response.headers, self.auth)
+        future.add_done_callback(updater.callback)
+
+
+class CrawlerScheduler(AbstractCrawler):
+
+    def __init__(self, username, password):
+        self.auth = (username, password)
+        super(CrawlerScheduler, self).__init__(self.auth)
+
+    def prepare_headers(self, feed):
+        headers = {}
+        if feed.get('etag', None):
+            headers['If-None-Match'] = feed['etag']
+        elif feed.get('last_modified'):
+            headers['If-Modified-Since'] = feed['last_modified']
+        logger.debug('%r %r - calculated headers %r',
+                     feed['id'], feed['title'], headers)
+        return headers
+
+    def callback(self, response):
+        response = response.result()
+        response.raise_for_status()
+        feeds = response.json()
+        logger.debug('%d to fetch %r', len(feeds), feeds)
+        for feed in feeds:
+            logger.info('%r %r - fetching resources',
+                        feed['id'], feed['title'])
+            future = self.session.get(feed['link'],
+                                      headers=self.prepare_headers(feed))
+            future.add_done_callback(FeedCrawler(feed, self.auth).callback)
+
+    def run(self):
+        logger.debug('retreving fetchable feed')
+        future = self.query_pyagg('get', 'feeds/fetchable')
+        future.add_done_callback(self.callback)
diff --git a/pyaggr3g470r/lib/utils.py b/pyaggr3g470r/lib/utils.py
new file mode 100644
index 00000000..a4f4b3ec
--- /dev/null
+++ b/pyaggr3g470r/lib/utils.py
@@ -0,0 +1,14 @@
+import types
+
+def default_handler(obj):
+    """JSON handler for default query formatting"""
+    if hasattr(obj, 'isoformat'):
+        return obj.isoformat()
+    if hasattr(obj, 'dump'):
+        return obj.dump()
+    if isinstance(obj, (set, frozenset, types.GeneratorType)):
+        return list(obj)
+    if isinstance(obj, BaseException):
+        return str(obj)
+    raise TypeError("Object of type %s with value of %r "
+                    "is not JSON serializable" % (type(obj), obj))