philo/validators.py

   1 from django.utils.translation import ugettext_lazy as _
   2 from django.core.validators import RegexValidator
   3 from django.core.exceptions import ValidationError
   4 from django.template import Template, Parser, Lexer, TOKEN_BLOCK, TOKEN_VAR, TemplateSyntaxError
   5 from django.utils import simplejson as json
   6 from django.utils.html import escape, mark_safe
   7 import re
   8 from philo.utils import LOADED_TEMPLATE_ATTR
   9
  10
  11 INSECURE_TAGS = (
  12         'load',
  13         'extends',
  14         'include',
  15         'debug',
  16 )
  17
  18
  19 class RedirectValidator(RegexValidator):
  20         """Based loosely on the URLValidator, but no option to verify_exists"""
  21         regex = re.compile(
  22                 r'^(?:https?://' # http:// or https://
  23                 r'(?:(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+[A-Z]{2,6}\.?|' #domain...
  24                 r'localhost|' #localhost...
  25                 r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})' # ...or ip
  26                 r'(?::\d+)?' # optional port
  27                 r'(?:/?|[/?#]?\S+)|'
  28                 r'[^?#\s]\S*)$',
  29                 re.IGNORECASE)
  30         message = _(u'Enter a valid absolute or relative redirect target')
  31
  32
  33 class URLLinkValidator(RegexValidator):
  34         """Based loosely on the URLValidator, but no option to verify_exists"""
  35         regex = re.compile(
  36                 r'^(?:https?://' # http:// or https://
  37                 r'(?:(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+[A-Z]{2,6}\.?|' #domain...
  38                 r'localhost|' #localhost...
  39                 r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})' # ...or ip
  40                 r'(?::\d+)?' # optional port
  41                 r'|)' # also allow internal links
  42                 r'(?:/?|[/?#]?\S+)$', re.IGNORECASE)
  43         message = _(u'Enter a valid absolute or relative redirect target')
  44
  45
  46 def json_validator(value):
  47         try:
  48                 json.loads(value)
  49         except Exception, e:
  50                 raise ValidationError(u'JSON decode error: %s' % e)
  51
  52
  53 class TemplateValidationParser(Parser):
  54         def __init__(self, tokens, allow=None, disallow=None, secure=True):
  55                 super(TemplateValidationParser, self).__init__(tokens)
  56
  57                 allow, disallow = set(allow or []), set(disallow or [])
  58
  59                 if secure:
  60                         disallow |= set(INSECURE_TAGS)
  61
  62                 self.allow, self.disallow, self.secure = allow, disallow, secure
  63
  64         def parse(self, parse_until=None):
  65                 if parse_until is None:
  66                         parse_until = []
  67
  68                 nodelist = self.create_nodelist()
  69                 while self.tokens:
  70                         token = self.next_token()
  71                         # We only need to parse var and block tokens.
  72                         if token.token_type == TOKEN_VAR:
  73                                 if not token.contents:
  74                                         self.empty_variable(token)
  75
  76                                 filter_expression = self.compile_filter(token.contents)
  77                                 var_node = self.create_variable_node(filter_expression)
  78                                 self.extend_nodelist(nodelist, var_node,token)
  79                         elif token.token_type == TOKEN_BLOCK:
  80                                 if token.contents in parse_until:
  81                                         # put token back on token list so calling code knows why it terminated
  82                                         self.prepend_token(token)
  83                                         return nodelist
  84
  85                                 try:
  86                                         command = token.contents.split()[0]
  87                                 except IndexError:
  88                                         self.empty_block_tag(token)
  89
  90                                 if (self.allow and command not in self.allow) or (self.disallow and command in self.disallow):
  91                                         self.disallowed_tag(command)
  92
  93                                 self.enter_command(command, token)
  94
  95                                 try:
  96                                         compile_func = self.tags[command]
  97                                 except KeyError:
  98                                         self.invalid_block_tag(token, command, parse_until)
  99
 100                                 try:
 101                                         compiled_result = compile_func(self, token)
 102                                 except TemplateSyntaxError, e:
 103                                         if not self.compile_function_error(token, e):
 104                                                 raise
 105
 106                                 self.extend_nodelist(nodelist, compiled_result, token)
 107                                 self.exit_command()
 108
 109                 if parse_until:
 110                         self.unclosed_block_tag(parse_until)
 111
 112                 return nodelist
 113
 114         def disallowed_tag(self, command):
 115                 if self.secure and command in INSECURE_TAGS:
 116                         raise ValidationError('Tag "%s" is not permitted for security reasons.' % command)
 117                 raise ValidationError('Tag "%s" is not permitted here.' % command)
 118
 119
 120 def linebreak_iter(template_source):
 121         # Cribbed from django/views/debug.py:18
 122         yield 0
 123         p = template_source.find('\n')
 124         while p >= 0:
 125                 yield p+1
 126                 p = template_source.find('\n', p+1)
 127         yield len(template_source) + 1
 128
 129
 130 class TemplateValidator(object):
 131         def __init__(self, allow=None, disallow=None, secure=True):
 132                 self.allow = allow
 133                 self.disallow = disallow
 134                 self.secure = secure
 135
 136         def __call__(self, value):
 137                 try:
 138                         self.validate_template(value)
 139                 except ValidationError:
 140                         raise
 141                 except Exception, e:
 142                         if hasattr(e, 'source') and isinstance(e, TemplateSyntaxError):
 143                                 origin, (start, end) = e.source
 144                                 template_source = origin.reload()
 145                                 upto = 0
 146                                 for num, next in enumerate(linebreak_iter(template_source)):
 147                                         if start >= upto and end <= next:
 148                                                 raise ValidationError(mark_safe("Template code invalid: \"%s\" (%s:%d).<br />%s" % (escape(template_source[start:end]), origin.loadname, num, e)))
 149                                         upto = next
 150                         raise ValidationError("Template code invalid. Error was: %s: %s" % (e.__class__.__name__, e))
 151
 152         def validate_template(self, template_string):
 153                 # We want to tokenize like normal, then use a custom parser.
 154                 lexer = Lexer(template_string, None)
 155                 tokens = lexer.tokenize()
 156                 parser = TemplateValidationParser(tokens, self.allow, self.disallow, self.secure)
 157
 158                 for node in parser.parse():
 159                         template = getattr(node, LOADED_TEMPLATE_ATTR, None)