蟒蛇3。 如何将下载的网页保存到指定的目录？

Question

I am trying to save all the < a > links within the python homepage into a folder named 'Downloaded pages'. However after 2 iterations through the for loop I receive the following error:

www.python.org#content <_io.BufferedWriter name='Downloaded Pages/www.python.org#content'> www.python.org#python-network <_io.BufferedWriter name='Downloaded Pages/www.python.org#python-network'>

Traceback (most recent call last): File "/Users/Lucas/Python/AP book exercise/Web Scraping/linkVerification.py", line 26, in downloadedPage = open(os.path.join('Downloaded Pages', os.path.basename(linkUrlToOpen)), 'wb') IsADirectoryError: [Errno 21] Is a directory: 'Downloaded Pages/'

I am unsure why this happens as it appears the pages are being saved as due to seeing '<_io.BufferedWriter name='Downloaded Pages/www.python.org#content'>', which says to me its the correct path.

This is my code:

import requests, os, bs4

# Create a new folder to download webpages to
os.makedirs('Downloaded Pages', exist_ok=True)

# Download webpage
url = 'https://www.python.org/'
res = requests.get(url)
res.raise_for_status() # Check if the download was successful

soupObj = bs4.BeautifulSoup(res.text, 'html.parser') # Collects all text form the webpage

# Find all 'a' links on the webpage
linkElem = soupObj.select('a')
numOfLinks = len(linkElem)

for i in range(numOfLinks):
    linkUrlToOpen = 'https://www.python.org' + linkElem[i].get('href')
    print(os.path.basename(linkUrlToOpen))

    # save each downloaded page to the 'Downloaded pages' folder
    downloadedPage = open(os.path.join('Downloaded Pages', os.path.basename(linkUrlToOpen)), 'wb')
    print(downloadedPage)
    if linkElem == []:
        print('Error, link does not work')
    else:
        for chunk in res.iter_content(100000):
            downloadedPage.write(chunk)
        downloadedPage.close()

Appreciate any advice, thanks.

Answer 1

The problem is that when you try to do things like parse the basename of a page with an .html dir it works, but when you try to do it with one that doesn't specify it on the url like "http://python.org/" the basename is actually empty (you can try printing first the url and then the basename bewteen brackets or something to see what i mean). So to work arround that, the easiest solution would be to use absolue paths like @Thyebri said.

And also, remember that the file you write cannot contain characters like '/', '\' or '?'

So, i dont know if the following code it's messy or not, but using the re library i would do the following:

filename = re.sub('[\/*:"?]+', '-', linkUrlToOpen.split("://")[1])
downloadedPage = open(os.path.join('Downloaded_Pages', filename), 'wb')

So, first i remove part i remove the "https://" part, and then with the regular expressions library i replace all the usual symbols that are present in url links with a dash '-' and that is the name that will be given to the file.

Hope it works!