| from __future__ import unicode_literals |
| |
| |
| class HostsLine(object): |
| def __init__(self, ip_address, canonical_hostname, aliases=None, comment=None): |
| self.ip_address = ip_address |
| self.canonical_hostname = canonical_hostname |
| self.aliases = aliases if aliases is not None else [] |
| self.comment = comment |
| if self.ip_address is None: |
| assert self.canonical_hostname is None |
| assert not self.aliases |
| assert self.comment is not None |
| |
| @classmethod |
| def from_string(cls, line): |
| if not line.strip(): |
| return |
| |
| line = line.strip() |
| |
| ip_address = None |
| canonical_hostname = None |
| aliases = [] |
| comment = None |
| |
| comment_parts = line.split("#", 1) |
| if len(comment_parts) > 1: |
| comment = comment_parts[1] |
| |
| data = comment_parts[0].strip() |
| |
| if data: |
| fields = data.split() |
| if len(fields) < 2: |
| raise ValueError("Invalid hosts line") |
| |
| ip_address = fields[0] |
| canonical_hostname = fields[1] |
| aliases = fields[2:] |
| |
| return cls(ip_address, canonical_hostname, aliases, comment) |
| |
| |
| class HostsFile(object): |
| def __init__(self): |
| self.data = [] |
| self.by_hostname = {} |
| |
| def set_host(self, host): |
| if host.canonical_hostname is None: |
| self.data.append(host) |
| elif host.canonical_hostname in self.by_hostname: |
| old_host = self.by_hostname[host.canonical_hostname] |
| old_host.ip_address = host.ip_address |
| old_host.aliases = host.aliases |
| old_host.comment = host.comment |
| else: |
| self.data.append(host) |
| self.by_hostname[host.canonical_hostname] = host |
| |
| @classmethod |
| def from_file(cls, f): |
| rv = cls() |
| for line in f: |
| host = HostsLine.from_string(line) |
| if host is not None: |
| rv.set_host(host) |
| return rv |
| |
| def to_string(self): |
| field_widths = [0, 0] |
| for line in self.data: |
| if line.ip_address is not None: |
| field_widths[0] = max(field_widths[0], len(line.ip_address)) |
| field_widths[1] = max(field_widths[1], len(line.canonical_hostname)) |
| |
| lines = [] |
| |
| for host in self.data: |
| line = "" |
| if host.ip_address is not None: |
| ip_string = host.ip_address.ljust(field_widths[0]) |
| hostname_str = host.canonical_hostname |
| if host.aliases: |
| hostname_str = "%s %s" % (hostname_str.ljust(field_widths[1]), |
| " ".join(host.aliases)) |
| line = "%s %s" % (ip_string, hostname_str) |
| if host.comment: |
| if line: |
| line += " " |
| line += "#%s" % host.comment |
| lines.append(line) |
| |
| lines.append("") |
| |
| return "\n".join(lines) |
| |
| def to_file(self, f): |
| f.write(self.to_string().encode("utf8")) |
