Scrapy脚本条件匹配失效及无详细报错问题求助

预期逻辑 #

读取Excel文件→提取车牌号码存入plate_num_xlsx变量（先赋默认值避免空值），通过Pandas逐个读取Excel A列的车牌值，发起请求并调用parse函数；在parse函数中执行以下逻辑：

plate = row.css('a::text').get()
price = row.css('p::text').get()
if plate_num_xlsx==plate.replace(" ","")

当Excel中的车牌值与网站解析的车牌值（去除空格后）匹配时，输出结果。

完整脚本代码 #

import scrapy
from scrapy.crawler import CrawlerProcess
import pandas as pd

plate_num_xlsx = 'LA55ERR'

class plateScraper(scrapy.Spider):
    name = 'scrapePlate'
    allowed_domains = ['dvlaregistrations.direct.gov.uk']
    start_urls = [f"https://dvlaregistrations.dvla.gov.uk/search/results.html?search={plate_num_xlsx}&action=index&pricefrom=0&priceto=&prefixmatches=&currentmatches=&limitprefix=&limitcurrent=&limitauction=&searched=true&openoption=&language=en&prefix2=Search&super=&super_pricefrom=&super_priceto="]

    def read_xlsx(self):
        df=pd.read_excel('data.xlsx')
        columnA_values=df['PLATES']
        for row in columnA_values:
            plate_num_xlsx=row
            yield scrapy.Request(start_urls.format(row))

    def parse(self, response):
        for row in response.css('div.resultsstrip'):
            plate = row.css('a::text').get()
            price = row.css('p::text').get()
            if plate_num_xlsx==plate.replace(" ",""):
                print(plate.replace(" ", ""))
                yield {"plate": plate.strip(), "price": price.strip()}

process = CrawlerProcess()
process.crawl(plateScraper)
process.start()

运行日志 #

C:\Users\Admin\AppData\Local\Programs\Python\Python310\python.exe C:/pythonPro/w_crawl/SimonDarak/scrpy_00.py 
2023-01-15 18:07:45 [scrapy.utils.log] INFO: Scrapy 2.7.1 started (bot: scrapybot)
2023-01-15 18:07:45 [scrapy.utils.log] INFO: Versions: lxml 4.9.1.0, libxml2 2.9.12, cssselect 1.2.0, parsel 1.7.0, w3lib 2.1.1, Twisted 22.10.0, Python 3.10.6 (tags/v3.10.6:9c7b4bd, Aug  1 2022, 21:53:49) [MSC v.1932 64 bit (AMD64)], pyOpenSSL 23.0.0 (OpenSSL 3.0.7 1 Nov 2022), cryptography 39.0.0, Platform Windows-10-10.0.19044-SP0
2023-01-15 18:07:45 [scrapy.crawler] INFO: Overridden settings:
{}
2023-01-15 18:07:45 [py.warnings] WARNING: C:\Users\Admin\AppData\Local\Programs\Python\Python310\lib\site-packages\scrapy\utils\request.py:231: ScrapyDeprecationWarning: '2.6' is a deprecated value for the 'REQUEST_FINGERPRINTER_IMPLEMENTATION' setting.

It is also the default value. In other words, it is normal to get this warning if you have not defined a value for the 'REQUEST_FINGERPRINTER_IMPLEMENTATION' setting. This is so for backward compatibility reasons, but it will change in a future version of Scrapy.

See the documentation of the 'REQUEST_FINGERPRINTER_IMPLEMENTATION' setting for information on how to handle this deprecation.
  return cls(crawler)

2023-01-15 18:07:45 [scrapy.utils.log] DEBUG: Using reactor: twisted.internet.selectreactor.SelectReactor
2023-01-15 18:07:45 [scrapy.extensions.telnet] INFO: Telnet Password: adce4fc71429f9ef
2023-01-15 18:07:45 [scrapy.middleware] INFO: Enabled extensions:
['scrapy.extensions.corestats.CoreStats',
 'scrapy.extensions.telnet.TelnetConsole',
 'scrapy.extensions.logstats.LogStats']
2023-01-15 18:07:46 [scrapy.middleware] INFO: Enabled downloader middlewares:
['scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware',
 'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware',
 'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware',
 'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware',
 'scrapy.downloadermiddlewares.retry.RetryMiddleware',
 'scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware',
 'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware',
 'scrapy.downloadermiddlewares.redirect.RedirectMiddleware',
 'scrapy.downloadermiddlewares.cookies.CookiesMiddleware',
 'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware',
 'scrapy.downloadermiddlewares.stats.DownloaderStats']
2023-01-15 18:07:46 [scrapy.middleware] INFO: Enabled spider middlewares:
['scrapy.spidermiddlewares.httperror.HttpErrorMiddleware',
 'scrapy.spidermiddlewares.offsite.OffsiteMiddleware',
 'scrapy.spidermiddlewares.referer.RefererMiddleware',
 'scrapy.spidermiddlewares.urllength.UrlLengthMiddleware',
 'scrapy.spidermiddlewares.depth.DepthMiddleware']
2023-01-15 18:07:46 [scrapy.middleware] INFO: Enabled item pipelines:
[]
2023-01-15 18:07:46 [scrapy.core.engine] INFO: Spider opened
2023-01-15 18:07:46 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2023-01-15 18:07:46 [scrapy.extensions.telnet] INFO: Telnet console listening on 127.0.0.1:6023
2023-01-15 18:07:47 [filelock] DEBUG: Attempting to acquire lock 2802896714000 on C:\Users\Admin\AppData\Local\Programs\Python\Python310\lib\site-packages\tldextract\.suffix_cache/publicsuffix.org-tlds\de84b5ca2167d4c83e38fb162f2e8738.tldextract.json.lock
2023-01-15 18:07:47 [filelock] DEBUG: Lock 2802896714000 acquired on C:\Users\Admin\AppData\Local\Programs\Python\Python310\lib\site-packages\tldextract\.suffix_cache/publicsuffix.org-tlds\de84b5ca2167d4c83e38fb162f2e8738.tldextract.json.lock
2023-01-15 18:07:47 [filelock] DEBUG: Attempting to release lock 2802896714000 on C:\Users\Admin\AppData\Local\Programs\Python\Python310\lib\site-packages\tldextract\.suffix_cache/publicsuffix.org-tlds\de84b5ca2167d4c83e38fb162f2e8738.tldextract.json.lock
2023-01-15 18:07:47 [filelock] DEBUG: Lock 2802896714000 released on C:\Users\Admin\AppData\Local\Programs\Python\Python310\lib\site-packages\tldextract\.suffix_cache/publicsuffix.org-tlds\de84b5ca2167d4c83e38fb162f2e8738.tldextract.json.lock
2023-01-15 18:07:47 [scrapy.core.engine] DEBUG: Crawled (200) <GET https://dvlaregistrations.dvla.gov.uk/search/results.html?search=LA55ERR&action=index&pricefrom=0&priceto=&prefixmatches=&currentmatches=&limitprefix=&limitcurrent=&limitauction=&searched=true&openoption=&language=en&prefix2=Search&super=&super_pricefrom=&super_priceto=> (referer: None)
2023-01-15 18:07:47 [scrapy.core.engine] INFO: Closing spider (finished)
2023-01-15 18:07:47 [scrapy.statscollectors] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 461,
 'downloader/request_count': 1,
 'downloader/request_method_count/GET': 1,
 'downloader/response_bytes': 11458,
 'downloader/response_count': 1,
 'downloader/response_status_count/200': 1,
 'elapsed_time_seconds': 0.709073,
 'finish_reason': 'finished',
 'finish_time': datetime.datetime(2023, 1, 15, 14, 7, 47, 140805),
 'httpcompression/response_bytes': 75657,
 'httpcompression/response_count': 1,
 'log_count/DEBUG': 6,
 'log_count/INFO': 10,
 'log_count/WARNING': 1,
 'response_received_count': 1,
 'scheduler/dequeued': 1,
 'scheduler/dequeued/memory': 1,
 'scheduler/enqueued': 1,
 'scheduler/enqueued/memory': 1,
 'start_time': datetime.datetime(2023, 1, 15, 14, 7, 46, 431732)}
2023-01-15 18:07:47 [scrapy.core.engine] INFO: Spider closed (finished)

Process finished with exit code 0

问题诊断与修复 #

脚本无输出的核心问题及对应修复方案如下：

1. 自定义读取Excel方法未触发 #

Scrapy默认只会执行start_urls中的请求，自定义的read_xlsx方法不会自动调用。需将Excel读取逻辑移至start_requests方法（Scrapy生成初始请求的标准入口）：

def start_requests(self):
    df = pd.read_excel('data.xlsx')
    columnA_values = df['PLATES']
    for row in columnA_values:
        # 跳过空值避免无效请求
        if pd.isna(row):
            continue
        url = f"https://dvlaregistrations.dvla.gov.uk/search/results.html?search={row}&action=index&pricefrom=0&priceto=&prefixmatches=&currentmatches=&limitprefix=&limitcurrent=&limitauction=&searched=true&openoption=&language=en&prefix2=Search&super=&super_pricefrom=&super_priceto="
        # 通过meta传递当前请求的车牌值
        yield scrapy.Request(url, meta={'plate_num_xlsx': row})

2. 车牌值无法正确传递到parse方法 #

原代码中read_xlsx里的plate_num_xlsx是局部变量，parse方法无法获取当前请求对应的车牌。需通过meta参数传递，在parse中取出使用：

def parse(self, response):
    plate_num_xlsx = response.meta['plate_num_xlsx']
    for row in response.css('div.resultsstrip'):
        plate = row.css('a::text').get()
        price = row.css('p::text').get()
        # 增加非空判断，避免AttributeError
        if plate and plate_num_xlsx == plate.replace(" ", ""):
            print(plate.replace(" ", ""))
            yield {"plate": plate.strip(), "price": price.strip()}

3. URL拼接错误 #

原代码中start_urls.format(row)会报错，因为start_urls是列表而非字符串。直接构造完整URL即可，如上述start_requests中的写法。

修复后的完整代码 #

import scrapy
from scrapy.crawler import CrawlerProcess
import pandas as pd

class plateScraper(scrapy.Spider):
    name = 'scrapePlate'
    allowed_domains = ['dvlaregistrations.direct.gov.uk']

    def start_requests(self):
        df = pd.read_excel('data.xlsx')
        columnA_values = df['PLATES']
        for row in columnA_values:
            if pd.isna(row):
                continue
            url = f"https://dvlaregistrations.dvla.gov.uk/search/results.html?search={row}&action=index&pricefrom=0&priceto=&prefixmatches=&currentmatches=&limitprefix=&limitcurrent=&limitauction=&searched=true&openoption=&language=en&prefix2=Search&super=&super_pricefrom=&super_priceto="
            yield scrapy.Request(url, meta={'plate_num_xlsx': row})

    def parse(self, response):
        plate_num_xlsx = response.meta['plate_num_xlsx']
        for row in response.css('div.resultsstrip'):
            plate = row.css('a::text').get()
            price = row.css('p::text').get()
            if plate and plate_num_xlsx == plate.replace(" ", ""):
                print(plate.replace(" ", ""))
                yield {"plate": plate.strip(), "price": price.strip()}

process = CrawlerProcess()
process.crawl(plateScraper)
process.start()

内容的提问来源于stack exchange，提问作者xlmaster