Python爬虫：Scrapy的get请求和post请求

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scrapy 请求继承体系

Request
	|-- FormRequest

通过以下请求测试
GET: https://httpbin.org/get
POST: https://httpbin.org/post

get请求

方式：通过Request 发送

import json

from scrapy import Spider, Request, cmdline


class SpiderRequest(Spider):
    name = "spider_request"

    def start_requests(self):
        url = "https://httpbin.org/get?name=tom"
        yield Request(url, body=json.dumps({"age": "23"}))

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


if __name__ == '__main__':
    cmdline.execute("scrapy crawl spider_request".split())

服务端收到url链接中的参数name，而没有收到body里边的参数age

"args": {
    "name": "tom"
  },

post请求

方式一：通过FormRequest 发送

from scrapy import Spider, cmdline, FormRequest


class SpiderFormData(Spider):
    name = "spider_form_data"

    def start_requests(self):
        url = "https://httpbin.org/post"
        yield FormRequest(url, formdata={"name": "Tom"})

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


if __name__ == '__main__':
    cmdline.execute("scrapy crawl spider_form_data".split())

服务器接收到参数

"form": {
    "name": "Tom"
  }, 

而且headers里边有一个参数

 "headers": {
    "Content-Type": "application/x-www-form-urlencoded", 
  }, 

方式二：通过Request发送

需要添加参数 method="POST"

import json

from scrapy import Spider, Request, cmdline


class SpiderPost(Spider):
    name = "spider_post"

    def start_requests(self):
        url = "https://httpbin.org/post"
        yield Request(url, method="POST", body=json.dumps({"name": "Tom"}))

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


if __name__ == '__main__':
    cmdline.execute("scrapy crawl spider_post".split())

1、直接发送post请求，服务器端收到参数data，和json：

"data": "{\"name\": \"Tom\"}", 
"form": {}, 
"json": {
    "name": "Tom"
  }, 

2、如果添加headers参数:

 "headers": {
    "Content-Type": "application/x-www-form-urlencoded", 
  }, 

服务器收到参数，form将接收到参数，也就是FormRequest的提交方式

"data": "", 
"form": {
    "{\"name\": \"Tom\"}": ""
  }, 
"json": null,

3、如果添加headers参数:

 "headers": {
    "Content-Type": "application/json", 
  }, 

服务器端将收到data 和json 参数，和第一个情形一样，不过有时候不加这个请求头参数获取，会请求错误

"data": "{\"name\": \"Tom\"}", 
"form": {}, 
"json": {
    "name": "Tom"
  }, 

总结

请求方式	使用方法	headers参数	参数	服务器端接收到参数
get	Request	-	?name=tom	args
post	FormRequest	有默认值	formdata={“name”: “Tom”}	form
post	Request	-	body=json.dumps({“name”: “Tom”})	data，json
post	Request	“Content-Type”: “application/x-www-form-urlencoded”	body=json.dumps({“name”: “Tom”})	form
post	Request	“Content-Type”: “application/json”,	body=json.dumps({“name”: “Tom”})	data， json

参考
Scrapy Requests and Responses