python 爬虫（五）

下载媒体文件

I 使用urllib.request.urlretrieve方法可以下载文件存为指定文件

from urllib.request import urlretrieve
from urllib.request import urlopen
from bs4 import BeautifulSoup

with urlopen("http://www.pythonscraping.com") as html:
    bsObj = BeautifulSoup(html,'html.parser')
imageLocation = bsObj.find('a',{'id':"logo"}).find("img")["src"]
urlretrieve(imageLocation,"logo.jpg")

import os
from urllib.request import urlretrieve
from urllib.request import urlopen
from bs4 import BeautifulSoup

downloadDirectory = "downloaded"
baseUrl = "http://pythonscraping.com"

def getAbsoluteURL(baseUrl, source):
    if source.startswith("http://www."):
        url = "http://" + source[11:]
    elif source.startswith("http://"):
        url = source
    elif source.startswith("www."):
        url = source[4:]
        url = "http://" + source
    else:
        url = baseUrl + "/" + source
    if baseUrl not in url:
        return None
    return url

def getDownLoadPath(baseUrl, absoluteUrl, downloadDirecory):
    path = absoluteUrl.replace("www.","")
    path = path.replace(baseUrl,"")
    path = downloadDirectory + path
    path = path.split("?")[0]
    directory = os.path.dirname(path)
    if not os.path.exists(directory):
        os.makedirs(directory)
    return path

html = urlopen("http://www.pythonscraping.com")
bsObj = BeautifulSoup(html,"html.parser")

downloadList = bsObj.find_all(src=True)

for download in downloadList:
    fileUrl = getAbsoluteURL(baseUrl, download["src"])
    if fileUrl is not None:
        print(fileUrl)
        dir = getDownLoadPath(baseUrl,fileUrl,downloadDirectory)
        print("save: " + dir)
        urlretrieve(fileUrl,dir)