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1 """ |
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2 This module converts requested URLs to callback view functions. |
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3 |
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4 RegexURLResolver is the main class here. Its resolve() method takes a URL (as |
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5 a string) and returns a tuple in this format: |
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6 |
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7 (view_function, function_args, function_kwargs) |
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8 """ |
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9 |
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10 from django.http import Http404 |
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11 from django.core.exceptions import ImproperlyConfigured, ViewDoesNotExist |
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12 from django.utils.encoding import iri_to_uri, force_unicode, smart_str |
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13 from django.utils.functional import memoize |
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14 import re |
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15 |
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16 try: |
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17 reversed |
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18 except NameError: |
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19 from django.utils.itercompat import reversed # Python 2.3 fallback |
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20 |
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21 _resolver_cache = {} # Maps urlconf modules to RegexURLResolver instances. |
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22 _callable_cache = {} # Maps view and url pattern names to their view functions. |
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23 |
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24 class Resolver404(Http404): |
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25 pass |
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26 |
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27 class NoReverseMatch(Exception): |
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28 # Don't make this raise an error when used in a template. |
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29 silent_variable_failure = True |
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30 |
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31 def get_callable(lookup_view, can_fail=False): |
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32 """ |
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33 Convert a string version of a function name to the callable object. |
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34 |
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35 If the lookup_view is not an import path, it is assumed to be a URL pattern |
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36 label and the original string is returned. |
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37 |
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38 If can_fail is True, lookup_view might be a URL pattern label, so errors |
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39 during the import fail and the string is returned. |
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40 """ |
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41 if not callable(lookup_view): |
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42 try: |
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43 # Bail early for non-ASCII strings (they can't be functions). |
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44 lookup_view = lookup_view.encode('ascii') |
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45 mod_name, func_name = get_mod_func(lookup_view) |
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46 if func_name != '': |
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47 lookup_view = getattr(__import__(mod_name, {}, {}, ['']), func_name) |
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48 except (ImportError, AttributeError): |
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49 if not can_fail: |
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50 raise |
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51 except UnicodeEncodeError: |
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52 pass |
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53 return lookup_view |
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54 get_callable = memoize(get_callable, _callable_cache, 1) |
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55 |
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56 def get_resolver(urlconf): |
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57 if urlconf is None: |
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58 from django.conf import settings |
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59 urlconf = settings.ROOT_URLCONF |
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60 return RegexURLResolver(r'^/', urlconf) |
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61 get_resolver = memoize(get_resolver, _resolver_cache, 1) |
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62 |
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63 def get_mod_func(callback): |
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64 # Converts 'django.views.news.stories.story_detail' to |
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65 # ['django.views.news.stories', 'story_detail'] |
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66 try: |
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67 dot = callback.rindex('.') |
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68 except ValueError: |
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69 return callback, '' |
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70 return callback[:dot], callback[dot+1:] |
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71 |
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72 def reverse_helper(regex, *args, **kwargs): |
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73 """ |
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74 Does a "reverse" lookup -- returns the URL for the given args/kwargs. |
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75 The args/kwargs are applied to the given compiled regular expression. |
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76 For example: |
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77 |
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78 >>> reverse_helper(re.compile('^places/(\d+)/$'), 3) |
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79 'places/3/' |
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80 >>> reverse_helper(re.compile('^places/(?P<id>\d+)/$'), id=3) |
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81 'places/3/' |
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82 >>> reverse_helper(re.compile('^people/(?P<state>\w\w)/(\w+)/$'), 'adrian', state='il') |
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83 'people/il/adrian/' |
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84 |
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85 Raises NoReverseMatch if the args/kwargs aren't valid for the regex. |
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86 """ |
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87 # TODO: Handle nested parenthesis in the following regex. |
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88 result = re.sub(r'\(([^)]+)\)', MatchChecker(args, kwargs), regex.pattern) |
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89 return result.replace('^', '').replace('$', '') |
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90 |
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91 class MatchChecker(object): |
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92 "Class used in reverse RegexURLPattern lookup." |
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93 def __init__(self, args, kwargs): |
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94 self.args, self.kwargs = args, kwargs |
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95 self.current_arg = 0 |
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96 |
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97 def __call__(self, match_obj): |
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98 # match_obj.group(1) is the contents of the parenthesis. |
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99 # First we need to figure out whether it's a named or unnamed group. |
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100 # |
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101 grouped = match_obj.group(1) |
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102 m = re.search(r'^\?P<(\w+)>(.*?)$', grouped, re.UNICODE) |
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103 if m: # If this was a named group... |
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104 # m.group(1) is the name of the group |
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105 # m.group(2) is the regex. |
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106 try: |
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107 value = self.kwargs[m.group(1)] |
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108 except KeyError: |
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109 # It was a named group, but the arg was passed in as a |
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110 # positional arg or not at all. |
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111 try: |
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112 value = self.args[self.current_arg] |
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113 self.current_arg += 1 |
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114 except IndexError: |
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115 # The arg wasn't passed in. |
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116 raise NoReverseMatch('Not enough positional arguments passed in') |
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117 test_regex = m.group(2) |
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118 else: # Otherwise, this was a positional (unnamed) group. |
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119 try: |
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120 value = self.args[self.current_arg] |
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121 self.current_arg += 1 |
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122 except IndexError: |
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123 # The arg wasn't passed in. |
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124 raise NoReverseMatch('Not enough positional arguments passed in') |
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125 test_regex = grouped |
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126 # Note we're using re.match here on purpose because the start of |
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127 # to string needs to match. |
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128 if not re.match(test_regex + '$', force_unicode(value), re.UNICODE): |
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129 raise NoReverseMatch("Value %r didn't match regular expression %r" % (value, test_regex)) |
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130 return force_unicode(value) |
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131 |
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132 class RegexURLPattern(object): |
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133 def __init__(self, regex, callback, default_args=None, name=None): |
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134 # regex is a string representing a regular expression. |
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135 # callback is either a string like 'foo.views.news.stories.story_detail' |
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136 # which represents the path to a module and a view function name, or a |
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137 # callable object (view). |
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138 self.regex = re.compile(regex, re.UNICODE) |
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139 if callable(callback): |
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140 self._callback = callback |
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141 else: |
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142 self._callback = None |
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143 self._callback_str = callback |
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144 self.default_args = default_args or {} |
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145 self.name = name |
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146 |
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147 def __repr__(self): |
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148 return '<%s %s %s>' % (self.__class__.__name__, self.name, self.regex.pattern) |
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149 |
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150 def add_prefix(self, prefix): |
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151 """ |
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152 Adds the prefix string to a string-based callback. |
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153 """ |
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154 if not prefix or not hasattr(self, '_callback_str'): |
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155 return |
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156 self._callback_str = prefix + '.' + self._callback_str |
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157 |
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158 def resolve(self, path): |
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159 match = self.regex.search(path) |
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160 if match: |
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161 # If there are any named groups, use those as kwargs, ignoring |
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162 # non-named groups. Otherwise, pass all non-named arguments as |
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163 # positional arguments. |
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164 kwargs = match.groupdict() |
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165 if kwargs: |
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166 args = () |
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167 else: |
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168 args = match.groups() |
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169 # In both cases, pass any extra_kwargs as **kwargs. |
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170 kwargs.update(self.default_args) |
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171 |
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172 return self.callback, args, kwargs |
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173 |
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174 def _get_callback(self): |
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175 if self._callback is not None: |
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176 return self._callback |
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177 try: |
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178 self._callback = get_callable(self._callback_str) |
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179 except ImportError, e: |
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180 mod_name, _ = get_mod_func(self._callback_str) |
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181 raise ViewDoesNotExist, "Could not import %s. Error was: %s" % (mod_name, str(e)) |
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182 except AttributeError, e: |
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183 mod_name, func_name = get_mod_func(self._callback_str) |
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184 raise ViewDoesNotExist, "Tried %s in module %s. Error was: %s" % (func_name, mod_name, str(e)) |
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185 return self._callback |
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186 callback = property(_get_callback) |
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187 |
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188 def reverse(self, viewname, *args, **kwargs): |
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189 mod_name, func_name = get_mod_func(viewname) |
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190 try: |
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191 lookup_view = getattr(__import__(mod_name, {}, {}, ['']), func_name) |
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192 except (ImportError, AttributeError): |
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193 raise NoReverseMatch |
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194 if lookup_view != self.callback: |
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195 raise NoReverseMatch |
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196 return self.reverse_helper(*args, **kwargs) |
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197 |
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198 def reverse_helper(self, *args, **kwargs): |
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199 return reverse_helper(self.regex, *args, **kwargs) |
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200 |
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201 class RegexURLResolver(object): |
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202 def __init__(self, regex, urlconf_name, default_kwargs=None): |
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203 # regex is a string representing a regular expression. |
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204 # urlconf_name is a string representing the module containing urlconfs. |
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205 self.regex = re.compile(regex, re.UNICODE) |
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206 self.urlconf_name = urlconf_name |
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207 self.callback = None |
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208 self.default_kwargs = default_kwargs or {} |
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209 self._reverse_dict = {} |
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210 |
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211 def __repr__(self): |
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212 return '<%s %s %s>' % (self.__class__.__name__, self.urlconf_name, self.regex.pattern) |
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213 |
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214 def _get_reverse_dict(self): |
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215 if not self._reverse_dict and hasattr(self.urlconf_module, 'urlpatterns'): |
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216 for pattern in reversed(self.urlconf_module.urlpatterns): |
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217 if isinstance(pattern, RegexURLResolver): |
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218 for key, value in pattern.reverse_dict.iteritems(): |
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219 self._reverse_dict[key] = (pattern,) + value |
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220 else: |
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221 self._reverse_dict[pattern.callback] = (pattern,) |
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222 self._reverse_dict[pattern.name] = (pattern,) |
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223 return self._reverse_dict |
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224 reverse_dict = property(_get_reverse_dict) |
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225 |
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226 def resolve(self, path): |
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227 tried = [] |
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228 match = self.regex.search(path) |
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229 if match: |
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230 new_path = path[match.end():] |
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231 for pattern in self.urlconf_module.urlpatterns: |
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232 try: |
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233 sub_match = pattern.resolve(new_path) |
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234 except Resolver404, e: |
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235 tried.extend([(pattern.regex.pattern + ' ' + t) for t in e.args[0]['tried']]) |
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236 else: |
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237 if sub_match: |
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238 sub_match_dict = dict([(smart_str(k), v) for k, v in match.groupdict().items()]) |
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239 sub_match_dict.update(self.default_kwargs) |
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240 for k, v in sub_match[2].iteritems(): |
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241 sub_match_dict[smart_str(k)] = v |
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242 return sub_match[0], sub_match[1], sub_match_dict |
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243 tried.append(pattern.regex.pattern) |
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244 raise Resolver404, {'tried': tried, 'path': new_path} |
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245 |
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246 def _get_urlconf_module(self): |
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247 try: |
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248 return self._urlconf_module |
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249 except AttributeError: |
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250 try: |
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251 self._urlconf_module = __import__(self.urlconf_name, {}, {}, ['']) |
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252 except Exception, e: |
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253 # Either an invalid urlconf_name, such as "foo.bar.", or some |
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254 # kind of problem during the actual import. |
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255 raise ImproperlyConfigured, "Error while importing URLconf %r: %s" % (self.urlconf_name, e) |
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256 return self._urlconf_module |
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257 urlconf_module = property(_get_urlconf_module) |
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258 |
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259 def _get_url_patterns(self): |
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260 return self.urlconf_module.urlpatterns |
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261 url_patterns = property(_get_url_patterns) |
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262 |
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263 def _resolve_special(self, view_type): |
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264 callback = getattr(self.urlconf_module, 'handler%s' % view_type) |
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265 mod_name, func_name = get_mod_func(callback) |
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266 try: |
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267 return getattr(__import__(mod_name, {}, {}, ['']), func_name), {} |
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268 except (ImportError, AttributeError), e: |
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269 raise ViewDoesNotExist, "Tried %s. Error was: %s" % (callback, str(e)) |
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270 |
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271 def resolve404(self): |
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272 return self._resolve_special('404') |
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273 |
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274 def resolve500(self): |
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275 return self._resolve_special('500') |
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276 |
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277 def reverse(self, lookup_view, *args, **kwargs): |
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278 try: |
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279 lookup_view = get_callable(lookup_view, True) |
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280 except (ImportError, AttributeError): |
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281 raise NoReverseMatch |
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282 if lookup_view in self.reverse_dict: |
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283 return u''.join([reverse_helper(part.regex, *args, **kwargs) for part in self.reverse_dict[lookup_view]]) |
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284 raise NoReverseMatch |
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285 |
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286 def reverse_helper(self, lookup_view, *args, **kwargs): |
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287 sub_match = self.reverse(lookup_view, *args, **kwargs) |
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288 result = reverse_helper(self.regex, *args, **kwargs) |
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289 return result + sub_match |
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290 |
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291 def resolve(path, urlconf=None): |
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292 return get_resolver(urlconf).resolve(path) |
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293 |
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294 def reverse(viewname, urlconf=None, args=None, kwargs=None): |
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295 args = args or [] |
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296 kwargs = kwargs or {} |
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297 return iri_to_uri(u'/' + get_resolver(urlconf).reverse(viewname, *args, **kwargs)) |
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298 |