SSHConfig parser should support Host lines with more than one host

[Gary Poster]

The config parser does not support Host files with more than one host. This is acceptable syntax, and it seems reasonable for paramiko to support it. The version of the SSHConfig object below has been changed to support the syntax.

class SSHConfig (object):
    """
    Representation of config information as stored in the format used by
    OpenSSH. Queries can be made via L{lookup}. The format is described in
    OpenSSH's C{ssh_config} man page. This class is provided primarily as a
    convenience to posix users (since the OpenSSH format is a de-facto
    standard on posix) but should work fine on Windows too.

    @since: 1.6
    """

    def __init__(self):
        """
        Create a new OpenSSH config object.
        """
        self._config = [ { 'host': '*' } ]

    def parse(self, file_obj):
        """
        Read an OpenSSH config from the given file object.

        @param file_obj: a file-like object to read the config file from
        @type file_obj: file
        """
        configs = [self._config[0]]
        for line in file_obj:
            line = line.rstrip('\n').lstrip()
            if (line == '') or (line[0] == '#'):
                continue
            if '=' in line:
                key, value = line.split('=', 1)
                key = key.strip().lower()
            else:
                # find first whitespace, and split there
                i = 0
                while (i < len(line)) and not line[i].isspace():
                    i += 1
                if i == len(line):
                    raise Exception('Unparsable line: %r' % line)
                key = line[:i].lower()
                value = line[i:].lstrip()

            if key == 'host':
                del configs[:]
                # the value may be multiple hosts, space-delimited
                for host in value.split():
                    # do we have a pre-existing host config to append to?
                    matches = [c for c in self._config if c['host'] == host]
                    if len(matches) > 0:
                        configs.append(matches[0])
                    else:
                        config = { 'host': host }
                        self._config.append(config)
                        configs.append(config)
            else:
                for config in configs:
                    config[key] = value

    def lookup(self, hostname):
        """
        Return a dict of config options for a given hostname.

        The host-matching rules of OpenSSH's C{ssh_config} man page are used,
        which means that all configuration options from matching host
        specifications are merged, with more specific hostmasks taking
        precedence. In other words, if C{"Port"} is set under C{"Host *"}
        and also C{"Host *.example.com"}, and the lookup is for
        C{"ssh.example.com"}, then the port entry for C{"Host *.example.com"}
        will win out.

        The keys in the returned dict are all normalized to lowercase (look for
        C{"port"}, not C{"Port"}. No other processing is done to the keys or
        values.

        @param hostname: the hostname to lookup
        @type hostname: str
        """
        matches = [x for x in self._config if fnmatch.fnmatch(hostname, x['host'])]
        # sort in order of shortest match (usually '*') to longest
        matches.sort(lambda x,y: cmp(len(x['host']), len(y['host'])))
        ret = {}
        for m in matches:
            ret.update(m)
        del ret['host']
        return ret

[Robey Pointer (robey)]

patch looks good; applying.