如何用Python下载网页上图像

如何用Python下载网页上图像

　　网络抓取是一种从网站获取数据的技术。在网上冲浪时，许多网站不允许用户保存数据供个人使用。一种方法是手动复制粘贴数据，这既乏味又耗时。网页抓取是从网站提取数据过程的自动化。在本文中，我们将讨论如何用Python下载网页上图像。

所需模块

• bs4： Beautiful Soup(bs4) 是一个用于从 HTML 和 XML 文件中提取数据的 Python 库。该模块不是 Python 内置的。
• requests：  Requests 允许您极其轻松地发送 HTTP/1.1 请求。该模块也不是内置于 Python 中的。
• os： python中的OS模块提供了与操作系统交互的功能。OS，属于Python 的标准实用程序模块。该模块提供了一种使用操作系统相关功能的可移植方式。

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方法

• 导入模块
• 获取 HTML 代码

　　使用 Beautiful Soup 中的findAll方法从 HTML 代码中获取img标签列表。

images = soup.findAll('img')

　　使用 os 中的mkdir方法创建单独的文件夹用于下载图像。

os.mkdir(folder_name)

　　遍历所有图像并获取该图像的源 URL。获取源URL后，最后一步是下载图像获取图像内容

r = requests.get(Source URL).content

　　使用文件处理下载图像

# Enter File Name with Extension like jpg, png etc..
with open("File Name","wb+") as f:
      f.write(r)

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使用Python下载网页上图像

from bs4 import *
import requests
import os

# CREATE FOLDER
def folder_create(images):
	try:
		folder_name = input("Enter Folder Name:- ")
		# folder creation
		os.mkdir(folder_name)

	# if folder exists with that name, ask another name
	except:
		print("Folder Exist with that name!")
		folder_create()

	# image downloading start
	download_images(images, folder_name)


# DOWNLOAD ALL IMAGES FROM THAT URL
def download_images(images, folder_name):

	# initial count is zero
	count = 0

	# print total images found in URL
	print(f"Total {len(images)} Image Found!")

	# checking if images is not zero
	if len(images) != 0:
		for i, image in enumerate(images):
			# From image tag ,Fetch image Source URL

						# 1.data-srcset
						# 2.data-src
						# 3.data-fallback-src
						# 4.src

			# Here we will use exception handling

			# first we will search for "data-srcset" in img tag
			try:
				# In image tag ,searching for "data-srcset"
				image_link = image["data-srcset"]
				
			# then we will search for "data-src" in img 
			# tag and so on..
			except:
				try:
					# In image tag ,searching for "data-src"
					image_link = image["data-src"]
				except:
					try:
						# In image tag ,searching for "data-fallback-src"
						image_link = image["data-fallback-src"]
					except:
						try:
							# In image tag ,searching for "src"
							image_link = image["src"]

						# if no Source URL found
						except:
							pass

			# After getting Image Source URL
			# We will try to get the content of image
			try:
				r = requests.get(image_link).content
				try:

					# possibility of decode
					r = str(r, 'utf-8')

				except UnicodeDecodeError:

					# After checking above condition, Image Download start
					with open(f"{folder_name}/images{i+1}.jpg", "wb+") as f:
						f.write(r)

					# counting number of image downloaded
					count += 1
			except:
				pass

		# There might be possible, that all
		# images not download
		# if all images download
		if count == len(images):
			print("All Images Downloaded!")
			
		# if all images not download
		else:
			print(f"Total {count} Images Downloaded Out of {len(images)}")

# MAIN FUNCTION START
def main(url):

	# content of URL
	r = requests.get(url)

	# Parse HTML Code
	soup = BeautifulSoup(r.text, 'html.parser')

	# find all images in URL
	images = soup.findAll('img')

	# Call folder create function
	folder_create(images)


# take url
url = input("Enter URL:- ")

# CALL MAIN FUNCTION
main(url)

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