Scrapy code can't accept arguments in Python script

Question

I'm attempting to run Scrapy within a Python script. Here's the relevant code:

import scrapy
from scrapy.crawler import CrawlerProcess

class PostSpider(scrapy.Spider):
    name = "post crawler"
    allowed_domains = ['test.com']

    def __init__(self, **kwargs):
        super(PostSpider, self).__init__(**kwargs)

        url = kwargs.get('url')
        print(url)
        self.start_urls = ['https://www.test.com/wp-json/test/2.0/posts' + url]

    def parse(self, response):
        post = json.loads(response.body_as_unicode())
        post = post["content"]
        return post

posts = GA.retrieve(TIA.start_date, TIA.end_date, "content type auto")

process = CrawlerProcess({
    'USER_AGENT': 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)'
}) 

for post in posts:
    post_url = post[2]
    process.crawl(PostSpider(url=post_url))
    process.start()

I'm attempting to follow the guidelines here and here somewhat. However, I can't get it to work. Here's the error message I received:

Unhandled error in Deferred:
2016-03-25 20:49:43 [twisted] CRITICAL: Unhandled error in Deferred:


Traceback (most recent call last):
  File "text_analysis.py", line 48, in <module>
    process.crawl(PostSpider(url=post_url))
  File "/Users/terence/TIA/lib/python3.5/site-packages/scrapy/crawler.py", line 163, in crawl
    return self._crawl(crawler, *args, **kwargs)
  File "/Users/terence/TIA/lib/python3.5/site-packages/scrapy/crawler.py", line 167, in _crawl
    d = crawler.crawl(*args, **kwargs)
  File "/Users/terence/TIA/lib/python3.5/site-packages/twisted/internet/defer.py", line 1274, in unwindGenerator
    return _inlineCallbacks(None, gen, Deferred())
--- <exception caught here> ---
  File "/Users/terence/TIA/lib/python3.5/site-packages/twisted/internet/defer.py", line 1128, in _inlineCallbacks
    result = g.send(result)
  File "/Users/terence/TIA/lib/python3.5/site-packages/scrapy/crawler.py", line 71, in crawl
    self.spider = self._create_spider(*args, **kwargs)
  File "/Users/terence/TIA/lib/python3.5/site-packages/scrapy/crawler.py", line 94, in _create_spider
    return self.spidercls.from_crawler(self, *args, **kwargs)
  File "/Users/terence/TIA/lib/python3.5/site-packages/scrapy/spiders/__init__.py", line 50, in from_crawler
    spider = cls(*args, **kwargs)
  File "text_analysis.py", line 17, in __init__
    self.start_urls = ['https://www.techinasia.com/wp-json/techinasia/2.0/posts' + url]
builtins.TypeError: Can't convert 'NoneType' object to str implicitly
2016-03-25 20:49:43 [twisted] CRITICAL: 
/xiaomi-still-got-it-bitches
2016-03-25 20:49:43 [scrapy] INFO: Enabled extensions:
['scrapy.extensions.corestats.CoreStats', 'scrapy.extensions.logstats.LogStats']

I can't seem to figure out what's wrong.

dron22 · Accepted Answer · 2016-03-25 13:15:02Z

4

The call of process.crawl() must be

process.crawl(PostSpider, url=post_url)

as the definition is

crawl(crawler_or_spidercls, *args, **kwargs)

It expects the spider class (not the instantiated object) as the first argument. All following positional and keyword arguments (*args, **kwargs) are passed on to the spider init function.

answered Mar 25, 2016 at 13:15

dron22

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Comments

paul trmbrth · Accepted Answer · 2016-03-25 13:14:51Z

2

CrawlerProcess.crawl expects a Spider class, not a Spider instance.

You should pass arguments like this:

process.crawl(PostSpider, url=post_url)

answered Mar 25, 2016 at 13:14

paul trmbrth

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