Scrapy 1.8.0返回错误500，但Python代码返回成功200

Question

地址是：“https://planningapi.agileapplications.co.uk/api/application/search?reference=GDO+19%2F12”

我可以通过Python请求库轻松下载此页面：

headers = {
            'x-client': 'EXMOOR',
            'x-product': 'CITIZENPORTAL',
            'x-service': 'PA',
            }
url='https://planningapi.agileapplications.co.uk/api/application/search?reference=GDO+19%2F12'
resp = requests.get(url, headers=headers)

或者我可以通过CURL轻松下载页面：

curl 'https://planningapi.agileapplications.co.uk/api/application/search?reference=GDO+19%2F12' -H 'x-product: CITIZENPORTAL' -H 'x-service: PA' -H 'x-client: EXMOOR'

它们都返回状态200结果：

{"total":1,"results":[{"id":18468,"reference":"GDO 19/12","proposal":"Prior notification for excavations to bury tanks and trenches to lay water pipes","location":"Land North West of North and South Ley, Exford, Minehead, Somerset.","username":"","applicantSurname":"Mr & Mrs M Burnett","agentName":"JCH Planning Limited","decisionText":null,"registrationDate":"2019-10-04","decisionDate":"2019-10-30","finalGrantDate":null,"appealLodgedDate":null,"appealDecisionDate":null,"areaId":[],"wardId":[],"parishId":[3],"responded":null,"lastLetterDate":null,"targetResponseDate":null}]}

但是Scrapy返回状态500错误：

formdata = {'reference': 'GDO 19/12', }

headers = {
    'x-client': 'EXMOOR',
    'x-product': 'CITIZENPORTAL',
    'x-service': 'PA',
    }

fr = scrapy.FormRequest(
    url='https://planningapi.agileapplications.co.uk/api/application/search',
    method='GET',
    meta=response.meta,
    headers=headers,
    formdata=formdata,
    dont_filter=True,
    callback=self.ref_result_2,
    )

yield fr

可能是因为Scrapy将标题键大写（我尝试过将它们取消大写，但Twisted也这样做了——它再次将它们大写），可能是出于其他原因

如何调整我的Scrapy 1.8.0代码以成功获得与Python请求相同的结果

Answer 1

这实际上是因为Scrapy将标题字段大写。如果您尝试在cURL命令中大写，那么您将得到与Scrapy相同的错误（您可以在spider类中的Scrapy设置handle_httpstatus_list中测试它，并在parse方法中打印response.text）。正如您已经说过的，Twisted也会这样做，因此覆盖scrapy.http.Headers不是解决方案

但是，您可以按照this issue comment的说明，使用技巧使Twisted不大写特定的头：

# -*- coding: utf-8 -*-
from pprint import pprint
import scrapy
from twisted.web.http_headers import Headers as TwistedHeaders

TwistedHeaders._caseMappings.update({
    b'x-client': b'x-client',
    b'x-product': b'x-product',
    b'x-service': b'x-service',
})

class Foo(scrapy.Spider):
    name = 'foo'
    handle_httpstatus_list = [500]

    def start_requests(self):
        formdata = {'reference': 'GDO 19/12'}
        headers = {
            'x-client': 'EXMOOR',
            'x-product': 'CITIZENPORTAL',
            'x-service': 'PA'
        }
        yield scrapy.FormRequest(
            'https://planningapi.agileapplications.co.uk/api/application/search',
            method='GET', headers=headers, formdata=formdata, callback=self.parse)

    def parse(self, response):
        pprint(response.text)

现在您将得到结果。另一方面，根据第3.2节RFC 7230，标题字段应不区分大小写