RPM Support

In [1]: url_slash = "https://dl.fedoraproject.org/pub/epel/7/x86_64/"                                                                                                                                                                         

In [2]: url = "https://dl.fedoraproject.org/pub/epel/7/x86_64"                                                                                                                                                                                

In [3]: from urllib.parse import urljoin                                                                                                                                                                                                      

In [4]: repomd = "repodata/repomd.xml"                                                                                                                                                                                                        

In [5]: urljoin(url_slash, repomd)                                                                                                                                                                                                            
Out[5]: 'https://dl.fedoraproject.org/pub/epel/7/x86_64/repodata/repomd.xml'

In [6]: urljoin(url, repomd)                                                                                                                                                                                                                  
Out[6]: 'https://dl.fedoraproject.org/pub/epel/7/repodata/repomd.xml'

Signature: urljoin(base, url, allow_fragments=True)
Source:   
def urljoin(base, url, allow_fragments=True):
    """Join a base URL and a possibly relative URL to form an absolute
    interpretation of the latter."""
    if not base:
        return url
    if not url:
        return base

    base, url, _coerce_result = _coerce_args(base, url)
    bscheme, bnetloc, bpath, bparams, bquery, bfragment = \
            urlparse(base, '', allow_fragments)
    scheme, netloc, path, params, query, fragment = \
            urlparse(url, bscheme, allow_fragments)

    if scheme != bscheme or scheme not in uses_relative:
        return _coerce_result(url)
    if scheme in uses_netloc:
        if netloc:
            return _coerce_result(urlunparse((scheme, netloc, path,
                                              params, query, fragment)))
        netloc = bnetloc

    if not path and not params:
        path = bpath
        params = bparams
        if not query:
            query = bquery
        return _coerce_result(urlunparse((scheme, netloc, path,
                                          params, query, fragment)))

    base_parts = bpath.split('/')
    if base_parts[-1] != '':
        # the last item is not a directory, so will not be taken into account
        # in resolving the relative path
        del base_parts[-1]

    # for rfc3986, ignore all base path should the first character be root.
    if path[:1] == '/':
        segments = path.split('/')
    else:
        segments = base_parts + path.split('/')
        # filter out elements that would cause redundant slashes on re-joining
        # the resolved_path
        segments[1:-1] = filter(None, segments[1:-1])

    resolved_path = []

    for seg in segments:
        if seg == '..':
            try:
                resolved_path.pop()
            except IndexError:
                # ignore any .. segments that would otherwise cause an IndexError
                # when popped from resolved_path if resolving for rfc3986
                pass
        elif seg == '.':
            continue
        else:
            resolved_path.append(seg)

    if segments[-1] in ('.', '..'):
        # do some post-processing here. if the last segment was a relative dir,
        # then we need to append the trailing '/'
        resolved_path.append('')

    return _coerce_result(urlunparse((scheme, netloc, '/'.join(
        resolved_path) or '/', params, query, fragment)))
File:      ~/.pyenv/versions/3.7.3/lib/python3.7/urllib/parse.py
Type:      function