# Standard Python library imports
# 3rd party modules
import pymongo
from scrapy import log
from scrapy.conf import settings
from scrapy.exceptions import DropItem
class MongoDBPipeline(object):
  def __init__(self):
    self.server = settings['MONGODB_SERVER']
    self.port = settings['MONGODB_PORT']
    self.db = settings['MONGODB_DB']
    self.col = settings['MONGODB_COLLECTION']
    connection = pymongo.Connection(self.server, self.port)
    db = connection[self.db]
    self.collection = db[self.col]
  def process_item(self, item, spider):
    err_msg = ''
    for field, data in item.items():
      if not data:
        err_msg += 'Missing %s of poem from %s\n' % (field, item['url'])
    if err_msg:
      raise DropItem(err_msg)
    self.collection.insert(dict(item))
    log.msg('Item written to MongoDB database %s/%s' % (self.db, self.col),
        level=log.DEBUG, spider=spider)
    return item