在请求中传递标题的影响? [英] Effects of passing headers in a requests?

问题描述

我想知道当您在requests.get中传递标题时有什么区别，即requests.get(url, headers)和requests.get(url)之间的区别.

I want to know what difference it makes when you pass headers in requests.get i.e. the difference between requests.get(url, headers) and requests.get(url).

我有这两段代码:

from lxml import html
from lxml import etree
import requests
import re

url = "http://www.amazon.in/SanDisk-micro-USB-connector-OTG-enabled-Android/dp/B00RBGYGMO"

page = requests.get(url)
tree = html.fromstring(page.text)
XPATH_IMAGE_SOURCE = '//*[@id="main-image-container"]//img/@src'
image_source = tree.xpath(XPATH_IMAGE_SOURCE)
print 'type: ',type(image_source[0])
print image_source[0]

其结果是您期望的网址.但这:

this whose out put is a url as you'd expect. But this:

from lxml import html
from lxml import etree
import requests
import re

url = "http://www.amazon.in/SanDisk-micro-USB-connector-OTG-enabled-Android/dp/B00RBGYGMO"
headers = {'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/42.0.2311.90 Safari/537.36'}
page = requests.get(url, headers=headers)

tree = html.fromstring(page.text)
XPATH_IMAGE_SOURCE = '//*[@id="main-image-container"]//img/@src'
image_source = tree.xpath(XPATH_IMAGE_SOURCE)
print 'type: ',type(image_source[0])
print image_source[0]

具有以data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAoHBwgHBgoIC开头的输出 我猜这是没有渲染的实际图像，只是纯数据.知道如何将其保留为url形式吗?标头的存在还会以其他方式影响我们得到的响应吗?

has an output that starts with data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAoHBwgHBgoIC I'm guessing this is the actual image without the rendering, just plain data. Any idea how I could keep it in url form? In what other ways does the presence of a header affect the response we get?

谢谢

推荐答案

将第一个代码的响应保存到html文件并在浏览器中打开:

Save the first code's response to html file and open in your browser:

如您所见，没有标题的亚马逊就禁止了您.

as you can see, you are banned by amazon without headers.

使用此xpath:

XPATH_IMAGE_SOURCE = '//*[@id="main-image-container"]//img/@data-old-hires'

退出:

type:  <class 'lxml.etree._ElementStringResult'>
http://ecx.images-amazon.com/images/I/617TjMIouyL._SL1274_.jpg

这是原始的html数据:

this is raw html data:

<img alt=".." src="&#10;data:image/webp;base64,UklGRuYIAABXRUJQVlA4INoIAACQQQCdASosAcsAPrFWpEqkIqQhIxN6gIgWCek6r4bUf/..." 
data-old-hires="http://ecx.images-amazon.com/images/I/617TjMIouyL._SL1274_.jpg"

图片网址位于data-old-hires属性中.

这篇关于在请求中传递标题的影响?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！