python尝试和除了url更正Python 3

Question

我正试图从网页上获取HTML。但是，并非所有URL都已正确编写。列表中的大多数无效URL都包含http，但现在URL正在使用https。有些人错过了“www。”，还有其他人“www。”需要添加。

def repl_www_http(url):
    x = url.replace("www.", "")
    y = x.replace("http", "https")
    return y

def repl_www(url):
    y = url.replace("www.", "")
    return y

def repl_http(url):
    y = url.replace("http", "https")
    return y

def repl_no_www(url):
    y = url.replace("//", "//www.")
    return y

def get_html(urllist):
        for i in urllist:
            html = ""
            try:
                html = requests.get(i)
                html = html.text
                return html
            except requests.exceptions.ConnectionError:
                try:
                    html = requests.get(repl_http(i))
                    html = html.text
                    print("replaced // with //www.")
                except requests.exceptions.ConnectionError:
                    try:
                        html = requests.get(repl_http(i))
                        html = html.text
                        print("replaced http with https")
                        return html
                    except requests.exceptions.ConnectionError:
                        try:
                            html = requests.get(repl_www(i))
                            html = html.text
                            print("replaced www. with .")
                            return html
                        except requests.exceptions.ConnectionError:
                            try:
                                html = requests.get(repl_www_http(i))
                                html = html.text
                                print("replaced www with . and http with https")
                                return html
                            except requests.exceptions.ConnectionError:
                                return "no HTML found on this URL"
        print("gethtml finished", html)

这是我得到的错误：

Traceback (most recent call last):  File "C:\replacer.py", line 76, in <module>    html = get_html(i)
  File "C:\replacer.py", line 37, in get_html    html = requests.get(repl_http(i))
  File "C:\Users\LorenzKort\AppData\Local\Programs\Python\Python37\lib\site-packages\requests-2.19.1-py3.7.egg\requests\api.py", line 72, in get
    return request('get', url, params=params, **kwargs)  File "C:\Users\LorenzKort\AppData\Local\Programs\Python\Python37\lib\site-packages\requests-2.19.1-py3.7.egg\requests\api.py", line 58, in request
    return session.request(method=method, url=url, **kwargs)  File "C:\Users\LorenzKort\AppData\Local\Programs\Python\Python37\lib\site-packages\requests-2.19.1-py3.7.egg\requests\sessions.py", line 498, in request
    prep = self.prepare_request(req)  File "C:\Users\LorenzKort\AppData\Local\Programs\Python\Python37\lib\site-packages\requests-2.19.1-py3.7.egg\requests\sessions.py", line 441, in prepare_request
    hooks=merge_hooks(request.hooks, self.hooks),
  File "C:\Users\LorenzKort\AppData\Local\Programs\Python\Python37\lib\site-packages\requests-2.19.1-py3.7.egg\requests\models.py",line 309, in prepare
    self.prepare_url(url, params)  File "C:\Users\LorenzKort\AppData\Local\Programs\Python\Python37\lib\site-packages\requests-2.19.1-py3.7.egg\requests\models.py",
line 383, in prepare_url
    raise MissingSchema(error)requests.exceptions.MissingSchema: Invalid URL 'h': No schema supplied. Perhaps you meant http://h?

如何解决此问题以纠正错误的URL？

Answer 1

问题是url传递给requests.get（）发送MissingSchema错误，你应该在捕获ConnectionError时捕获此错误。

我认为你应该使用生成器来清理你的代码，因为你不应该像这样嵌入try / catch语句。

def get_versions_url(my_url):
    yield my_url
    yield repl_www(my_url)
    yield repl_http(my_url)
    yield repl_http_www(my_url)

def get_html(urllist):
    #use i only for indexes
    for my_url in urllist:
        for url_fixed in get_versions_url(my_url):
            try:
                # I dind't figure out why you return here and do not end first loop
                return requests.get(url_fixed).text
            except requests.exceptions.ConnectionError:
                pass
            except requests.exceptions.MissingSchema:
                pass

然后你可以调试你的发电机。试着做 ：

for url in fix_url(<your url>):
    print(url)

我认为你的一些repl_函数不能像你期望的那样工作。