| commit | author | age | ||
| 52fde9 | 1 | import functools |
| d8d3a9 | 2 | from hashlib import md5 |
| 52fde9 | 3 | import traceback |
| f2294f | 4 | from webob.acceptparse import Accept |
| 52fde9 | 5 | from zope.interface import implementer |
| 5bf23f | 6 | |
| ee117e | 7 | from pyramid.compat import ( |
| CM | 8 | bytes_, |
| 9c120b | 9 | is_nonstr_iter |
| 52fde9 | 10 | ) |
| MM | 11 | from pyramid.interfaces import IActionInfo |
| ee117e | 12 | |
| 5bf23f | 13 | from pyramid.exceptions import ConfigurationError |
| 52fde9 | 14 | from pyramid.predicates import Notted |
| d98612 | 15 | from pyramid.registry import predvalseq |
| d8d3a9 | 16 | from pyramid.util import ( |
| CM | 17 | TopologicalSorter, |
| 52fde9 | 18 | takes_one_arg, |
| MM | 19 | ) |
| d8d3a9 | 20 | |
| 52fde9 | 21 | TopologicalSorter = TopologicalSorter # support bw-compat imports |
| MM | 22 | takes_one_arg = takes_one_arg # support bw-compat imports |
| 23 | ||
| 24 | @implementer(IActionInfo) | |
| 25 | class ActionInfo(object): | |
| 26 | def __init__(self, file, line, function, src): | |
| 27 | self.file = file | |
| 28 | self.line = line | |
| 29 | self.function = function | |
| 30 | self.src = src | |
| 31 | ||
| 32 | def __str__(self): | |
| 33 | srclines = self.src.split('\n') | |
| 34 | src = '\n'.join(' %s' % x for x in srclines) | |
| 35 | return 'Line %s of file %s:\n%s' % (self.line, self.file, src) | |
| 36 | ||
| 37 | def action_method(wrapped): | |
| 38 | """ Wrapper to provide the right conflict info report data when a method | |
| 39 | that calls Configurator.action calls another that does the same. Not a | |
| 40 | documented API but used by some external systems.""" | |
| 41 | def wrapper(self, *arg, **kw): | |
| 42 | if self._ainfo is None: | |
| 43 | self._ainfo = [] | |
| 44 | info = kw.pop('_info', None) | |
| 45 | # backframes for outer decorators to actionmethods | |
| 46 | backframes = kw.pop('_backframes', 0) + 2 | |
| 47 | if is_nonstr_iter(info) and len(info) == 4: | |
| 48 | # _info permitted as extract_stack tuple | |
| 49 | info = ActionInfo(*info) | |
| 50 | if info is None: | |
| 51 | try: | |
| 52 | f = traceback.extract_stack(limit=4) | |
| 53 | ||
| 54 | # Work around a Python 3.5 issue whereby it would insert an | |
| 55 | # extra stack frame. This should no longer be necessary in | |
| 56 | # Python 3.5.1 | |
| 57 | last_frame = ActionInfo(*f[-1]) | |
| 58 | if last_frame.function == 'extract_stack': # pragma: no cover | |
| 59 | f.pop() | |
| 60 | info = ActionInfo(*f[-backframes]) | |
| 61 | except Exception: # pragma: no cover | |
| 62 | info = ActionInfo(None, 0, '', '') | |
| 63 | self._ainfo.append(info) | |
| 64 | try: | |
| 65 | result = wrapped(self, *arg, **kw) | |
| 66 | finally: | |
| 67 | self._ainfo.pop() | |
| 68 | return result | |
| 69 | ||
| 70 | if hasattr(wrapped, '__name__'): | |
| 71 | functools.update_wrapper(wrapper, wrapped) | |
| 72 | wrapper.__docobj__ = wrapped | |
| 73 | return wrapper | |
| 74 | ||
| 5bf23f | 75 | |
| CM | 76 | MAX_ORDER = 1 << 30 |
| 77 | DEFAULT_PHASH = md5().hexdigest() | |
| 52fde9 | 78 | |
| 561591 | 79 | |
| 32333e | 80 | class not_(object): |
| 49f7c3 | 81 | """ |
| CM | 82 | |
| 83 | You can invert the meaning of any predicate value by wrapping it in a call | |
| 84 | to :class:`pyramid.config.not_`. | |
| 85 | ||
| 86 | .. code-block:: python | |
| 87 | :linenos: | |
| 88 | ||
| 89 | from pyramid.config import not_ | |
| 90 | ||
| 91 | config.add_view( | |
| 92 | 'mypackage.views.my_view', | |
| 08422e | 93 | route_name='ok', |
| 49f7c3 | 94 | request_method=not_('POST') |
| CM | 95 | ) |
| 96 | ||
| 97 | The above example will ensure that the view is called if the request method | |
| 98 | is *not* ``POST``, at least if no other view is more specific. | |
| 99 | ||
| 100 | This technique of wrapping a predicate value in ``not_`` can be used | |
| 101 | anywhere predicate values are accepted: | |
| 102 | ||
| 103 | - :meth:`pyramid.config.Configurator.add_view` | |
| 104 | ||
| 105 | - :meth:`pyramid.config.Configurator.add_route` | |
| 106 | ||
| 107 | - :meth:`pyramid.config.Configurator.add_subscriber` | |
| 108 | ||
| 109 | - :meth:`pyramid.view.view_config` | |
| 110 | ||
| 111 | - :meth:`pyramid.events.subscriber` | |
| 112 | ||
| 113 | .. versionadded:: 1.5 | |
| 114 | """ | |
| 32333e | 115 | def __init__(self, value): |
| CM | 116 | self.value = value |
| 117 | ||
| 118 | ||
| fc3f23 | 119 | # under = after |
| CM | 120 | # over = before |
| a00621 | 121 | |
| CM | 122 | class PredicateList(object): |
| 08422e | 123 | |
| a00621 | 124 | def __init__(self): |
| CM | 125 | self.sorter = TopologicalSorter() |
| 9c8ec5 | 126 | self.last_added = None |
| a00621 | 127 | |
| CM | 128 | def add(self, name, factory, weighs_more_than=None, weighs_less_than=None): |
| 9c8ec5 | 129 | # Predicates should be added to a predicate list in (presumed) |
| CM | 130 | # computation expense order. |
| 131 | ## if weighs_more_than is None and weighs_less_than is None: | |
| 132 | ## weighs_more_than = self.last_added or FIRST | |
| 133 | ## weighs_less_than = LAST | |
| 134 | self.last_added = name | |
| 0ccdc2 | 135 | self.sorter.add( |
| CM | 136 | name, |
| 137 | factory, | |
| 138 | after=weighs_more_than, | |
| 139 | before=weighs_less_than, | |
| 140 | ) | |
| a00621 | 141 | |
| 51ee34 | 142 | def names(self): |
| BJR | 143 | # Return the list of valid predicate names. |
| 144 | return self.sorter.names | |
| 145 | ||
| 9c8ec5 | 146 | def make(self, config, **kw): |
| CM | 147 | # Given a configurator and a list of keywords, a predicate list is |
| 148 | # computed. Elsewhere in the code, we evaluate predicates using a | |
| 149 | # generator expression. All predicates associated with a view or | |
| 150 | # route must evaluate true for the view or route to "match" during a | |
| 151 | # request. The fastest predicate should be evaluated first, then the | |
| 152 | # next fastest, and so on, as if one returns false, the remainder of | |
| 153 | # the predicates won't need to be evaluated. | |
| 154 | # | |
| 155 | # While we compute predicates, we also compute a predicate hash (aka | |
| 156 | # phash) that can be used by a caller to identify identical predicate | |
| 157 | # lists. | |
| a00621 | 158 | ordered = self.sorter.sorted() |
| CM | 159 | phash = md5() |
| 160 | weights = [] | |
| 9c8ec5 | 161 | preds = [] |
| CM | 162 | for n, (name, predicate_factory) in enumerate(ordered): |
| a00621 | 163 | vals = kw.pop(name, None) |
| 9c8ec5 | 164 | if vals is None: # XXX should this be a sentinel other than None? |
| a00621 | 165 | continue |
| 9c8ec5 | 166 | if not isinstance(vals, predvalseq): |
| a00621 | 167 | vals = (vals,) |
| CM | 168 | for val in vals: |
| 32333e | 169 | realval = val |
| CM | 170 | notted = False |
| 171 | if isinstance(val, not_): | |
| 172 | realval = val.value | |
| 173 | notted = True | |
| 174 | pred = predicate_factory(realval, config) | |
| 175 | if notted: | |
| 176 | pred = Notted(pred) | |
| 9c8ec5 | 177 | hashes = pred.phash() |
| a00621 | 178 | if not is_nonstr_iter(hashes): |
| CM | 179 | hashes = [hashes] |
| 180 | for h in hashes: | |
| 181 | phash.update(bytes_(h)) | |
| 25c64c | 182 | weights.append(1 << n + 1) |
| 9c8ec5 | 183 | preds.append(pred) |
| a00621 | 184 | if kw: |
| 96dd80 | 185 | from difflib import get_close_matches |
| 08422e | 186 | closest = [] |
| FL | 187 | names = [ name for name, _ in ordered ] |
| 188 | for name in kw: | |
| 189 | closest.extend(get_close_matches(name, names, 3)) | |
| 190 | ||
| 191 | raise ConfigurationError( | |
| 192 | 'Unknown predicate values: %r (did you mean %s)' | |
| 193 | % (kw, ','.join(closest)) | |
| 194 | ) | |
| 9c8ec5 | 195 | # A "order" is computed for the predicate list. An order is |
| CM | 196 | # a scoring. |
| 197 | # | |
| 198 | # Each predicate is associated with a weight value. The weight of a | |
| 199 | # predicate symbolizes the relative potential "importance" of the | |
| 200 | # predicate to all other predicates. A larger weight indicates | |
| 201 | # greater importance. | |
| 202 | # | |
| 203 | # All weights for a given predicate list are bitwise ORed together | |
| 204 | # to create a "score"; this score is then subtracted from | |
| 205 | # MAX_ORDER and divided by an integer representing the number of | |
| 206 | # predicates+1 to determine the order. | |
| 207 | # | |
| 208 | # For views, the order represents the ordering in which a "multiview" | |
| 209 | # ( a collection of views that share the same context/request/name | |
| 210 | # triad but differ in other ways via predicates) will attempt to call | |
| 211 | # its set of views. Views with lower orders will be tried first. | |
| 212 | # The intent is to a) ensure that views with more predicates are | |
| 213 | # always evaluated before views with fewer predicates and b) to | |
| 214 | # ensure a stable call ordering of views that share the same number | |
| 215 | # of predicates. Views which do not have any predicates get an order | |
| 216 | # of MAX_ORDER, meaning that they will be tried very last. | |
| a00621 | 217 | score = 0 |
| CM | 218 | for bit in weights: |
| 219 | score = score | bit | |
| 9c8ec5 | 220 | order = (MAX_ORDER - score) / (len(preds) + 1) |
| CM | 221 | return order, preds, phash.hexdigest() |
| f2294f | 222 | |
| MM | 223 | |
| 4a9f4f | 224 | def normalize_accept_offer(offer, verify=True): |
| MM | 225 | if verify: |
| 226 | Accept.parse_offer(offer) | |
| 227 | return offer.lower() | |
| 228 | ||
| 229 | ||
| f2294f | 230 | def sort_accept_offers(offers, order=None): |
| MM | 231 | """ |
| 4a9f4f | 232 | Sort a list of offers by preference. |
| f2294f | 233 | |
| 4a9f4f | 234 | For a given ``type/subtype`` category of offers, this algorithm will |
| MM | 235 | always sort offers with params higher than the bare offer. |
| f2294f | 236 | |
| MM | 237 | :param offers: A list of offers to be sorted. |
| 238 | :param order: A weighted list of offers where items closer to the start of | |
| 239 | the list will be a preferred over items closer to the end. | |
| 240 | :return: A list of offers sorted first by specificity (higher to lower) | |
| 241 | then by ``order``. | |
| 242 | ||
| 243 | """ | |
| 244 | if order is None: | |
| 245 | order = [] | |
| 246 | ||
| 247 | max_weight = len(offers) | |
| 248 | ||
| 249 | def find_order_index(value, default=None): | |
| 250 | return next((i for i, x in enumerate(order) if x == value), default) | |
| 251 | ||
| 252 | def offer_sort_key(value): | |
| 253 | """ | |
| 4a9f4f | 254 | (type_weight, params_weight) |
| f2294f | 255 | |
| MM | 256 | type_weight: |
| 4a9f4f | 257 | - index of specific ``type/subtype`` in order list |
| f2294f | 258 | - ``max_weight * 2`` if no match is found |
| MM | 259 | |
| 260 | params_weight: | |
| 261 | - index of specific ``type/subtype;params`` in order list | |
| 262 | - ``max_weight`` if not found | |
| 263 | - ``max_weight + 1`` if no params at all | |
| 264 | ||
| 265 | """ | |
| 266 | parsed = Accept.parse_offer(value) | |
| 267 | ||
| 4a9f4f | 268 | type_w = find_order_index( |
| MM | 269 | parsed.type + '/' + parsed.subtype, |
| 270 | max_weight, | |
| 271 | ) | |
| f2294f | 272 | |
| MM | 273 | if parsed.params: |
| 274 | param_w = find_order_index(value, max_weight) | |
| 275 | ||
| 276 | else: | |
| 277 | param_w = max_weight + 1 | |
| 278 | ||
| 4a9f4f | 279 | return (type_w, param_w) |
| f2294f | 280 | |
| MM | 281 | return sorted(offers, key=offer_sort_key) |
