"""
ldapurl - handling of LDAP URLs as described in RFC 4516

See http://www.python-ldap.org/ for details.

\$Id: ldapurl.py,v 1.58 2012/06/07 18:40:59 stroeder Exp $

Python compability note:
This module only works with Python 2.0+ since
1. string methods are used instead of module string and
2. list comprehensions are used.
"""

__version__ = '2.4.10'

__all__ = [
  # constants
  'SEARCH_SCOPE','SEARCH_SCOPE_STR',
  'LDAP_SCOPE_BASE','LDAP_SCOPE_ONELEVEL','LDAP_SCOPE_SUBTREE',
  # functions
  'isLDAPUrl',
  # classes
  'LDAPUrlExtension','LDAPUrlExtensions','LDAPUrl'
]

import UserDict

from urllib import quote,unquote

LDAP_SCOPE_BASE = 0
LDAP_SCOPE_ONELEVEL = 1
LDAP_SCOPE_SUBTREE = 2

SEARCH_SCOPE_STR = {None:'',0:'base',1:'one',2:'sub'}

SEARCH_SCOPE = {
  '':None,
  # the search scope strings defined in RFC2255
  'base':LDAP_SCOPE_BASE,
  'one':LDAP_SCOPE_ONELEVEL,
  'sub':LDAP_SCOPE_SUBTREE,
}

# Some widely used types
StringType = type('')
TupleType=type(())


def isLDAPUrl(s):
  """
  Returns 1 if s is a LDAP URL, 0 else
  """
  s_lower = s.lower()
  return \
    s_lower.startswith('ldap://') or \
    s_lower.startswith('ldaps://') or \
    s_lower.startswith('ldapi://')


def ldapUrlEscape(s):
  """Returns URL encoding of string s"""
  return quote(s).replace(',','%2C').replace('/','%2F')


class LDAPUrlExtension:
  """
  Class for parsing and unparsing LDAP URL extensions
  as described in RFC 4516.

  Usable class attributes:
    critical
          Boolean integer marking the extension as critical
    extype    
          Type of extension
    exvalue
          Value of extension
  """

  def __init__(self,extensionStr=None,critical=0,extype=None,exvalue=None):
    self.critical = critical
    self.extype = extype
    self.exvalue = exvalue
    if extensionStr:
      self._parse(extensionStr)

  def _parse(self,extension):
    extension = extension.strip()
    if not extension:
      # Don't parse empty strings
      self.extype,self.exvalue = None,None
      return
    self.critical = extension[0]=='!'
    if extension[0]=='!':
      extension = extension[1:].strip()
    try:
      self.extype,self.exvalue = extension.split('=',1)
    except ValueError:
      # No value, just the extype
      self.extype,self.exvalue = extension,None
    else:
      self.exvalue = unquote(self.exvalue.strip())
    self.extype = self.extype.strip()

  def unparse(self):
    if self.exvalue is None:
      return '%s%s' % ('!'*(self.critical>0),self.extype)
    else:
      return '%s%s=%s' % (
        '!'*(self.critical>0),
        self.extype,quote(self.exvalue or '')
      )
    
  def __str__(self):
    return self.unparse()

  def __repr__(self):
    return '<%s.%s instance at %s: %s>' % (
      self.__class__.__module__,
      self.__class__.__name__,
      hex(id(self)),
      self.__dict__
    )

  def __eq__(self,other):
    return \
      (self.critical==other.critical) and \
      (self.extype==other.extype) and \
      (self.exvalue==other.exvalue)

  def __ne__(self,other):
    return not self.__eq__(other)


class LDAPUrlExtensions(UserDict.UserDict):
  """
  Models a collection of LDAP URL extensions as
  dictionary type
  """

  def __init__(self,default=None):
    UserDict.UserDict.__init__(self)
    for k,v in (default or {}).items():
      self[k]=v

  def __setitem__(self,name,value):
    """
    value
        Either LDAPUrlExtension instance, (critical,exvalue)
        or string'ed exvalue
    """
    assert isinstance(value,LDAPUrlExtension)
    assert name==value.extype
    self.data[name] = value

  def values(self):
    return [
      self[k]
      for k in self.keys()
    ]

  def __str__(self):
    return ','.join(map(str,self.values()))

  def __repr__(self):
    return '<%s.%s instance at %s: %s>' % (
      self.__class__.__module__,
      self.__class__.__name__,
      hex(id(self)),
      self.data
    )

  def __eq__(self,other):
    assert isinstance(other,self.__class__),TypeError(
      "other has to be instance of %s" % (self.__class__)
    )
    return self.data==other.data
    
  def parse(self,extListStr):
    for extension_str in extListStr.strip().split(','):
      if extension_str:
        e = LDAPUrlExtension(extension_str)
        self[e.extype] = e

  def unparse(self):
    return ','.join([ v.unparse() for v in self.values() ])


class LDAPUrl:
  """
  Class for parsing and unparsing LDAP URLs
  as described in RFC 4516.

  Usable class attributes:
    urlscheme
        URL scheme (either ldap, ldaps or ldapi)
    hostport
        LDAP host (default '')
    dn
        String holding distinguished name (default '')
    attrs
        list of attribute types (default None)
    scope
        integer search scope for ldap-module
    filterstr
        String representation of LDAP Search Filters
        (see RFC 4515)
    extensions
        Dictionary used as extensions store
    who
        Maps automagically to bindname LDAP URL extension
    cred
        Maps automagically to X-BINDPW LDAP URL extension
  """

  attr2extype = {'who':'bindname','cred':'X-BINDPW'}

  def __init__(
    self,
    ldapUrl=None,
    urlscheme='ldap',
    hostport='',dn='',attrs=None,scope=None,filterstr=None,
    extensions=None,
    who=None,cred=None
  ):
    self.urlscheme=urlscheme
    self.hostport=hostport
    self.dn=dn
    self.attrs=attrs
    self.scope=scope
    self.filterstr=filterstr
    self.extensions=(extensions or LDAPUrlExtensions({}))
    if ldapUrl!=None:
      self._parse(ldapUrl)
    if who!=None:
      self.who = who
    if cred!=None:
      self.cred = cred

  def __eq__(self,other):
    return \
      self.urlscheme==other.urlscheme and \
      self.hostport==other.hostport and \
      self.dn==other.dn and \
      self.attrs==other.attrs and \
      self.scope==other.scope and \
      self.filterstr==other.filterstr and \
      self.extensions==other.extensions

  def __ne__(self,other):
    return not self.__eq__(other)

  def _parse(self,ldap_url):
    """
    parse a LDAP URL and set the class attributes
    urlscheme,host,dn,attrs,scope,filterstr,extensions
    """
    if not isLDAPUrl(ldap_url):
      raise ValueError,'Parameter ldap_url does not seem to be a LDAP URL.'
    scheme,rest = ldap_url.split('://',1)
    self.urlscheme = scheme.strip()
    if not self.urlscheme in ['ldap','ldaps','ldapi']:
      raise ValueError,'LDAP URL contains unsupported URL scheme %s.' % (self.urlscheme)
    slash_pos = rest.find('/')
    qemark_pos = rest.find('?')
    if (slash_pos==-1) and (qemark_pos==-1):
      # No / and ? found at all
      self.hostport = unquote(rest)
      self.dn = ''
      return
    else:
      if slash_pos!=-1 and (qemark_pos==-1 or (slash_pos<qemark_pos)):
        # Slash separates DN from hostport
        self.hostport = unquote(rest[:slash_pos])
        # Eat the slash from rest
        rest = rest[slash_pos+1:]
      elif qemark_pos!=1 and (slash_pos==-1 or (slash_pos>qemark_pos)):
        # Question mark separates hostport from rest, DN is assumed to be empty
        self.hostport = unquote(rest[:qemark_pos])
        # Do not eat question mark
        rest = rest[qemark_pos:]
      else:
        raise ValueError,'Something completely weird happened!'
    paramlist=rest.split('?',4)
    paramlist_len = len(paramlist)
    if paramlist_len>=1:
      self.dn = unquote(paramlist[0]).strip()
    if (paramlist_len>=2) and (paramlist[1]):
      self.attrs = unquote(paramlist[1].strip()).split(',')
    if paramlist_len>=3:
      scope = paramlist[2].strip()
      try:
        self.scope = SEARCH_SCOPE[scope]
      except KeyError:
        raise ValueError,"Search scope must be either one of base, one or sub. LDAP URL contained %s" % (repr(scope))
    if paramlist_len>=4:
      filterstr = paramlist[3].strip()
      if not filterstr:
        self.filterstr = None
      else:
        self.filterstr = unquote(filterstr)
    if paramlist_len>=5:
      if paramlist[4]:
        self.extensions = LDAPUrlExtensions()
        self.extensions.parse(paramlist[4])
      else:
        self.extensions = None
    return

  def applyDefaults(self,defaults):
    """
    Apply defaults to all class attributes which are None.

    defaults
        Dictionary containing a mapping from class attributes
        to default values
    """
    for k in defaults.keys():
      if getattr(self,k) is None:
        setattr(self,k,defaults[k])

  def initializeUrl(self):
    """
    Returns LDAP URL suitable to be passed to ldap.initialize()
    """
    if self.urlscheme=='ldapi':
      # hostport part might contain slashes when ldapi:// is used
      hostport = ldapUrlEscape(self.hostport)
    else:
      hostport = self.hostport
    return '%s://%s' % (self.urlscheme,hostport)

  def unparse(self):
    """
    Returns LDAP URL depending on class attributes set.
    """
    if self.attrs is None:
      attrs_str = ''
    else:
      attrs_str = ','.join(self.attrs)
    scope_str = SEARCH_SCOPE_STR[self.scope]
    if self.filterstr is None:
      filterstr = ''
    else:
      filterstr = ldapUrlEscape(self.filterstr)
    dn = ldapUrlEscape(self.dn)
    if self.urlscheme=='ldapi':
      # hostport part might contain slashes when ldapi:// is used
      hostport = ldapUrlEscape(self.hostport)
    else:
      hostport = self.hostport
    ldap_url = '%s://%s/%s?%s?%s?%s' % (
      self.urlscheme,
      hostport,dn,attrs_str,scope_str,filterstr
    )
    if self.extensions:
      ldap_url = ldap_url+'?'+self.extensions.unparse()
    return ldap_url
  
  def htmlHREF(self,urlPrefix='',hrefText=None,hrefTarget=None):
    """
    Returns a string with HTML link for this LDAP URL.
    
    urlPrefix
        Prefix before LDAP URL (e.g. for addressing another web-based client)
    hrefText
        link text/description
    hrefTarget
        string added as link target attribute
    """
    assert type(urlPrefix)==StringType, "urlPrefix must be StringType"
    if hrefText is None:
      hrefText = self.unparse()
    assert type(hrefText)==StringType, "hrefText must be StringType"
    if hrefTarget is None:
      target = ''
    else:
      assert type(hrefTarget)==StringType, "hrefTarget must be StringType"
      target = ' target="%s"' % hrefTarget
    return '<a%s href="%s%s">%s</a>' % (
      target,urlPrefix,self.unparse(),hrefText
    )

  def __str__(self):
    return self.unparse()

  def __repr__(self):
    return '<%s.%s instance at %s: %s>' % (
      self.__class__.__module__,
      self.__class__.__name__,
      hex(id(self)),
      self.__dict__
    )

  def __getattr__(self,name):
    if self.attr2extype.has_key(name):
      extype = self.attr2extype[name]
      if self.extensions and \
         self.extensions.has_key(extype) and \
         not self.extensions[extype].exvalue is None:
        result = unquote(self.extensions[extype].exvalue)
      else:
        return None
    else:
      raise AttributeError,"%s has no attribute %s" % (
        self.__class__.__name__,name
      )
    return result # __getattr__()

  def __setattr__(self,name,value):
    if self.attr2extype.has_key(name):
      extype = self.attr2extype[name]
      if value is None:
        # A value of None means that extension is deleted
        delattr(self,name)
      elif value!=None:
        # Add appropriate extension
        self.extensions[extype] = LDAPUrlExtension(
          extype=extype,exvalue=unquote(value)
        )
    else:
      self.__dict__[name] = value

  def __delattr__(self,name):
    if self.attr2extype.has_key(name):
      extype = self.attr2extype[name]
      if self.extensions:
        try:
          del self.extensions[extype]
        except KeyError:
          pass
    else:
      del self.__dict__[name]

