使用 BeautifulSoup 美化方法的 Python 出现奇怪错误

Question

I got the following problem. I wrote a simple "TextBasedBrowser" (if you can even call it browser at this point:D). The website scraping and parsing with BS4 works great so far, but the its formatted like shit and pretty much unreadable. As soon as I try to use the prettify() method from BS4 it throws me an AttributeError. I searched quite a while on google but couldnt find anything. This is my Code (prettify() method is commented out there):

from bs4 import BeautifulSoup
import requests
import sys
import os

legal_html_tags = ['p', 'a', 'ul', 'ol', 'li', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'title']
saved_pages = []


def search_url(url):
    saved_pages.append(url.rstrip(".com"))
    url = requests.get(f'https://{url}')
    return url.text


def parse_html(html_page):
    final_text = ""
    soup = BeautifulSoup(html_page, 'html.parser')
    # soup = soup.prettify()
    plain_text = soup.find_all(text=True)
    for t in plain_text:
        if t.parent.name in legal_html_tags:
            final_text += '{} '.format(t)
    return final_text


def save_webpage(url, tb_dir):
    with open(f'{tb_dir}/{url.rstrip(".com")}.txt', 'w', encoding="utf-8") as tab:
        tab.write(parse_html(search_url(url)))


def check_url(url):
    if url.endswith(".com") or url.endswith(".org") or url.endswith(".net"):
        return True
    else:
        return False


args = sys.argv
directory = args[1]
try:
    os.mkdir(directory)
except FileExistsError:
    print("Error: File already exists")

while True:
    url_ = input()
    if url_ == "exit":
        break
    elif url_ in saved_pages:
        with open(f'{directory}/{url_}.txt', 'r', encoding="utf-8") as curr_page:
            print(curr_page.read())
    elif not check_url(url_):
        print("Error: Invalid URL")
    else:
        save_webpage(url_, directory)
        print(parse_html(search_url(url_)))

And this is the Error:

Traceback (most recent call last):
  File "browser.py", line 56, in <module>
    save_webpage(url_, directory)
  File "browser.py", line 29, in save_webpage
    tab.write(parse_html(search_url(url)))
  File "browser.py", line 20, in parse_html
    plain_text = soup.find_all(text=True)
AttributeError: 'str' object has no attribute 'find_all'

If I include the encoding parameter in the prettify() method it throws me 'bytes' instead of 'str' object.

Answer 1

prettify turns your parsed HTML object into a string, so you can't call find_all on it. Maybe you just want to return soup.prettify() ? This might be what you want:

def parse_html(html_page):
    final_text = ""
    soup = BeautifulSoup(html_page, 'html.parser')
    plain_text = soup.find_all(text=True)
    for t in plain_text:
        if t.parent.name in legal_html_tags:
            final_text += t.prettify() + " "
    return final_text

Answer 2

You have re-assigned the soup variable into a string using the.prettify() method

soup = soup.prettify()

find_all() is a method for soup objects only

You should call find_all(text = True) first and extract all html tags with text, then you perform string operations.