Pipeline doesn't write to MySQL but also gives no error - mysql

Question

I've tried to implement this pipeline in my spider.
After installing the necessary dependencies I am able to run the spider without any errors but for some reason it doesn't write to my database.
I'm pretty sure there is something going wrong with connecting to the database. When I give in a wrong password, I still don't get any error.
When the spider scraped all the data, it needs a few minutes before it starts dumping the stats.
2017-08-31 13:17:12 [scrapy] INFO: Closing spider (finished)
2017-08-31 13:17:12 [scrapy] INFO: Stored csv feed (27 items) in: test.csv
2017-08-31 13:24:46 [scrapy] INFO: Dumping Scrapy stats:
Pipeline:
import MySQLdb.cursors
from twisted.enterprise import adbapi
from scrapy.xlib.pydispatch import dispatcher
from scrapy import signals
from scrapy.utils.project import get_project_settings
from scrapy import log
SETTINGS = {}
SETTINGS['DB_HOST'] = 'mysql.domain.com'
SETTINGS['DB_USER'] = 'username'
SETTINGS['DB_PASSWD'] = 'password'
SETTINGS['DB_PORT'] = 3306
SETTINGS['DB_DB'] = 'database_name'
class MySQLPipeline(object):
#classmethod
def from_crawler(cls, crawler):
return cls(crawler.stats)
def __init__(self, stats):
print "init"
#Instantiate DB
self.dbpool = adbapi.ConnectionPool ('MySQLdb',
host=SETTINGS['DB_HOST'],
user=SETTINGS['DB_USER'],
passwd=SETTINGS['DB_PASSWD'],
port=SETTINGS['DB_PORT'],
db=SETTINGS['DB_DB'],
charset='utf8',
use_unicode = True,
cursorclass=MySQLdb.cursors.DictCursor
)
self.stats = stats
dispatcher.connect(self.spider_closed, signals.spider_closed)
def spider_closed(self, spider):
print "close"
""" Cleanup function, called after crawing has finished to close open
objects.
Close ConnectionPool. """
self.dbpool.close()
def process_item(self, item, spider):
print "process"
query = self.dbpool.runInteraction(self._insert_record, item)
query.addErrback(self._handle_error)
return item
def _insert_record(self, tx, item):
print "insert"
result = tx.execute(
" INSERT INTO matches(type,home,away,home_score,away_score) VALUES (soccer,"+item["home"]+","+item["away"]+","+item["score"].explode("-")[0]+","+item["score"].explode("-")[1]+")"
)
if result > 0:
self.stats.inc_value('database/items_added')
def _handle_error(self, e):
print "error"
log.err(e)
Spider:
import scrapy
import dateparser
from crawling.items import KNVBItem
class KNVBspider(scrapy.Spider):
name = "knvb"
start_urls = [
'http://www.knvb.nl/competities/eredivisie/uitslagen',
]
custom_settings = {
'ITEM_PIPELINES': {
'crawling.pipelines.MySQLPipeline': 301,
}
}
def parse(self, response):
# www.knvb.nl/competities/eredivisie/uitslagen
for row in response.xpath('//div[#class="table"]'):
for div in row.xpath('./div[#class="row"]'):
match = KNVBItem()
match['home'] = div.xpath('./div[#class="value home"]/div[#class="team"]/text()').extract_first()
match['away'] = div.xpath('./div[#class="value away"]/div[#class="team"]/text()').extract_first()
match['score'] = div.xpath('./div[#class="value center"]/text()').extract_first()
match['date'] = dateparser.parse(div.xpath('./preceding-sibling::div[#class="header"]/span/span/text()').extract_first(), languages=['nl']).strftime("%d-%m-%Y")
yield match
If there are better pipelines available to do what I'm trying to achieve that'd be welcome as well. Thanks!
Update:
With the link provided in the accepted answer I eventually got to this function that's working (and thus solved my problem):
def process_item(self, item, spider):
print "process"
query = self.dbpool.runInteraction(self._insert_record, item)
query.addErrback(self._handle_error)
query.addBoth(lambda _: item)
return query

Answer 1

Take a look at this for how to use adbapi with MySQL for saving scraped items. Note the difference in your process_item and their process_item method implementation. While you return the item immediately, they return Deferred object which is the result of runInteraction method and which returns the item upon its completion. I think this is the reason your _insert_record never gets called.

Answer 2

If you can see the insert in your output that's already a good sign.
I'd rewrite the insert function this way:
def _insert_record(self, tx, item):
print "insert"
raw_sql = "INSERT INTO matches(type,home,away,home_score,away_score) VALUES ('%s', '%s', '%s', '%s', '%s')"
sql = raw_sql % ('soccer', item['home'], item['away'], item['score'].explode('-')[0], item['score'].explode('-')[1])
print sql
result = tx.execute(sql)
if result > 0:
self.stats.inc_value('database/items_added')
It allows you to debug the sql you're using. In you version you're not wrapping the string in ' which is a syntax error in mysql.
I'm not sure about your last values (score) so I treated them as strings.