动态组装scrapy GET请求字符串 [英] Dynamically assembling scrapy GET request string

问题描述

我一直在使用 firebug，我有以下字典来查询 api.

I've been working with firebug and I've got the following dictionaries to query an api.

url = "htp://my_url.aspx#top"

querystring = {"dbkey":"x1","stype":"id","s":"27"}

headers = {
    'accept': "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8",
    'upgrade-insecure-requests': "1",
    'user-agent': "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/44.0.2403.125 
    }

对于python请求，使用起来很简单:

with python requests, using this is as simple as:

import requests
response = requests.request("GET", url, headers=headers, params=querystring)
print(response.text)

如何在 Scrapy 中使用这些?我一直在阅读 http://doc.scrapy.org/en/latest/topics/request-response.html 并且我知道以下内容适用于发布:

How can I use these in Scrapy? I've been reading http://doc.scrapy.org/en/latest/topics/request-response.html and I know that the following works for post:

        r = Request(my_url, method="post",  headers= headers, body=payload, callback=self.parse_method)

我试过了:

    r = Request("GET", url, headers=headers, body=querystring, callback=self.parse_third_request)

我得到:

r = Request("GET", url, headers=headers, body=querystring, callback=self.parse_third_request)
TypeError: __init__() got multiple values for keyword argument 'callback'

改为:

    r = Request(method="GET", url=url, headers=headers, body=querystring, callback=self.parse_third_request)

现在得到:

  File "C:\envs\r2\tutorial\tutorial\spiders\parker_spider.py", line 90, in parse_second_request
    r = Request(method="GET", url=url, headers=headers, body=querystring, callback=self.parse_third_request)
  File "C:\envs\virtalenvs\teat\lib\site-packages\scrapy\http\request\__init__.py", line 26, in __init__
    self._set_body(body)
  File "C:\envs\virtalenvs\teat\lib\site-packages\scrapy\http\request\__init__.py", line 68, in _set_body
    self._body = to_bytes(body, self.encoding)
  File "C:\envs\virtalenvs\teat\lib\site-packages\scrapy\utils\python.py", line 117, in to_bytes
    'object, got %s' % type(text).__name__)
TypeError: to_bytes must receive a unicode, str or bytes object, got dict

编辑 2:

我现在有:

    yield Request(method="GET", url=url, headers=headers, body=urllib.urlencode(querystring), callback=self.parse_third_request)

def parse_third_request(self, response):
    from scrapy.shell import inspect_response
    inspect_response(response, self)
    print("hi")
    return None

没有错误，但在 shell 中，当我执行response.url"时，我只得到没有获取参数的基本 url.

There are no errors but in the shell when I do "response.url" I only get the base url with no get parameters.

推荐答案

看Request初始化方法的签名:

class scrapy.http.Request(url[, callback, method='GET', headers, body, cookies, meta, encoding='utf-8', priority=0, dont_filter=False, errback])

GET 字符串在您的情况下用作 callback 参数的位置值.

GET string in your case is used as a positional value for the callback argument.

使用 关键字参数代替 method(尽管 GET 是默认值):

Use a keyword argument for the method instead (though GET is the default):

r = Request(url, method="GET", headers=headers, body=querystring, callback=self.parse_third_request)

这篇关于动态组装scrapy GET请求字符串的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！