Merge branch 'master' of git://github.com/melinath/philo
[philo.git] / 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
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)