Pagination 刮痧'；s分页错误

嗨，伙计们，我在抓取一个网站时遇到了以下分页错误

2017-07-27 18:30:21 [scrapy.core.scraper] ERROR: Spider error processing <GET https://www.pedidosja.com.br/restaurantes/sao-paulo?a=rua%20tenente%20negr%C3%A3o%20200&cep=04530030&doorNumber=200&bairro=Itaim%20Bibi&lat=-23.585202&lng=-46.671715199999994> (referer: None)
Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/scrapy/utils/defer.py", line 102, in iter_errback
    yield next(it)
  File "/usr/local/lib/python3.5/dist-packages/scrapy/spidermiddlewares/offsite.py", line 29, in process_spider_output
    for x in result:
  File "/usr/local/lib/python3.5/dist-packages/scrapy/spidermiddlewares/referer.py", line 339, in <genexpr>
    return (_set_referer(r) for r in result or ())
  File "/usr/local/lib/python3.5/dist-packages/scrapy/spidermiddlewares/urllength.py", line 37, in <genexpr>
    return (r for r in result or () if _filter(r))
  File "/usr/local/lib/python3.5/dist-packages/scrapy/spidermiddlewares/depth.py", line 58, in <genexpr>
    return (r for r in result or () if _filter(r))
  File "/root/Documents/Spiders/pedidosYa/pedidosYa/spiders/pedidosya.py", line 35, in parse
    next_page_url = response.urljoin(next_page_url)
  File "/usr/local/lib/python3.5/dist-packages/scrapy/http/response/text.py", line 82, in urljoin
    return urljoin(get_base_url(self), url)
  File "/usr/lib/python3.5/urllib/parse.py", line 416, in urljoin
    base, url, _coerce_result = _coerce_args(base, url)
  File "/usr/lib/python3.5/urllib/parse.py", line 112, in _coerce_args
    raise TypeError("Cannot mix str and non-str arguments")
TypeError: Cannot mix str and non-str arguments
2017-07-27 18:30:21 [scrapy.core.engine] INFO: Closing spider (finished)
2017-07-27 18:30:21 [scrapy.extensions.feedexport] INFO: Stored csv feed (13 items) in: test3.csv
2017-07-27 18:30:21 [scrapy.statscollectors] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 653,
 'downloader/request_count': 2,
 'downloader/request_method_count/GET': 2,
 'downloader/response_bytes': 62571,
 'downloader/response_count': 2,
 'downloader/response_status_count/200': 2,
 'finish_reason': 'finished',
 'finish_time': datetime.datetime(2017, 7, 27, 23, 30, 21, 221038),
 'item_scraped_count': 13,
 'log_count/DEBUG': 16,
 'log_count/ERROR': 1,
 'log_count/INFO': 8,
 'memusage/max': 49278976,
 'memusage/startup': 49278976,
 'response_received_count': 2,
 'scheduler/dequeued': 1,
 'scheduler/dequeued/memory': 1,
 'scheduler/enqueued': 1,
 'scheduler/enqueued/memory': 1,
 'spider_exceptions/TypeError': 1,
 'start_time': datetime.datetime(2017, 7, 27, 23, 30, 17, 538310)}
2017-07-27 18:30:21 [scrapy.core.engine] INFO: Spider closed (finished)

提前谢谢你，祝你度过美好的一天

next_page_url = response.css('li.arrow.next > a ::attr(href)').extract()
                                                              ^^^^^^^^^^
if next_page_url:
    next_page_url = response.urljoin(next_page_url)
                                     ^^^^^^^^^^^^^

在这里，您正在列表上调用

urljoin

，因为创建

next\u page\u url

时

extract（）

方法返回所有值的列表，即使它只是一个成员。
要解决此问题，请改用

extract\u first（）

：

next_page_url = response.css('li.arrow.next > a ::attr(href)').extract_first()
                                                               ^^^^^^^^^^^^^^^

---

问题出在这一行：

next_page_url = response.css('li.arrow.next > a::attr(href)').extract()

因为

extract（）。或者使用
extract\u first（）
方法，该方法将仅给出第一个结果：

next_page_url = response.css('li.arrow.next > a::attr(href)').extract_first()

或者自己获取结果列表的第一个元素：

next_page_url = response.css('li.arrow.next > a::attr(href)').extract()[0]

next_page_url = response.css('li.arrow.next > a::attr(href)').extract()[0]