| 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 | |
| 0c29cf | 7 | from pyramid.compat import bytes_, is_nonstr_iter |
| 52fde9 | 8 | from pyramid.interfaces import IActionInfo |
| ee117e | 9 | |
| 5bf23f | 10 | from pyramid.exceptions import ConfigurationError |
| 52fde9 | 11 | from pyramid.predicates import Notted |
| d98612 | 12 | from pyramid.registry import predvalseq |
| 0c29cf | 13 | from pyramid.util import TopologicalSorter, takes_one_arg |
| d8d3a9 | 14 | |
| 52fde9 | 15 | TopologicalSorter = TopologicalSorter # support bw-compat imports |
| MM | 16 | takes_one_arg = takes_one_arg # support bw-compat imports |
| 0c29cf | 17 | |
| 52fde9 | 18 | |
| MM | 19 | @implementer(IActionInfo) |
| 20 | class ActionInfo(object): | |
| 21 | def __init__(self, file, line, function, src): | |
| 22 | self.file = file | |
| 23 | self.line = line | |
| 24 | self.function = function | |
| 25 | self.src = src | |
| 26 | ||
| 27 | def __str__(self): | |
| 28 | srclines = self.src.split('\n') | |
| 29 | src = '\n'.join(' %s' % x for x in srclines) | |
| 30 | return 'Line %s of file %s:\n%s' % (self.line, self.file, src) | |
| 31 | ||
| 0c29cf | 32 | |
| 52fde9 | 33 | def action_method(wrapped): |
| MM | 34 | """ Wrapper to provide the right conflict info report data when a method |
| 35 | that calls Configurator.action calls another that does the same. Not a | |
| 36 | documented API but used by some external systems.""" | |
| 0c29cf | 37 | |
| 52fde9 | 38 | def wrapper(self, *arg, **kw): |
| MM | 39 | if self._ainfo is None: |
| 40 | self._ainfo = [] | |
| 41 | info = kw.pop('_info', None) | |
| 42 | # backframes for outer decorators to actionmethods | |
| 43 | backframes = kw.pop('_backframes', 0) + 2 | |
| 44 | if is_nonstr_iter(info) and len(info) == 4: | |
| 45 | # _info permitted as extract_stack tuple | |
| 46 | info = ActionInfo(*info) | |
| 47 | if info is None: | |
| 48 | try: | |
| 49 | f = traceback.extract_stack(limit=4) | |
| 50 | ||
| 51 | # Work around a Python 3.5 issue whereby it would insert an | |
| 52 | # extra stack frame. This should no longer be necessary in | |
| 53 | # Python 3.5.1 | |
| 54 | last_frame = ActionInfo(*f[-1]) | |
| 0c29cf | 55 | if last_frame.function == 'extract_stack': # pragma: no cover |
| 52fde9 | 56 | f.pop() |
| MM | 57 | info = ActionInfo(*f[-backframes]) |
| 0c29cf | 58 | except Exception: # pragma: no cover |
| 52fde9 | 59 | info = ActionInfo(None, 0, '', '') |
| MM | 60 | self._ainfo.append(info) |
| 61 | try: | |
| 62 | result = wrapped(self, *arg, **kw) | |
| 63 | finally: | |
| 64 | self._ainfo.pop() | |
| 65 | return result | |
| 66 | ||
| 67 | if hasattr(wrapped, '__name__'): | |
| 68 | functools.update_wrapper(wrapper, wrapped) | |
| 69 | wrapper.__docobj__ = wrapped | |
| 70 | return wrapper | |
| 71 | ||
| 5bf23f | 72 | |
| CM | 73 | MAX_ORDER = 1 << 30 |
| 74 | DEFAULT_PHASH = md5().hexdigest() | |
| 52fde9 | 75 | |
| 561591 | 76 | |
| 32333e | 77 | class not_(object): |
| 49f7c3 | 78 | """ |
| CM | 79 | |
| 80 | You can invert the meaning of any predicate value by wrapping it in a call | |
| 81 | to :class:`pyramid.config.not_`. | |
| 82 | ||
| 83 | .. code-block:: python | |
| 84 | :linenos: | |
| 85 | ||
| 86 | from pyramid.config import not_ | |
| 87 | ||
| 88 | config.add_view( | |
| 89 | 'mypackage.views.my_view', | |
| 08422e | 90 | route_name='ok', |
| 49f7c3 | 91 | request_method=not_('POST') |
| CM | 92 | ) |
| 93 | ||
| 94 | The above example will ensure that the view is called if the request method | |
| 95 | is *not* ``POST``, at least if no other view is more specific. | |
| 96 | ||
| 97 | This technique of wrapping a predicate value in ``not_`` can be used | |
| 98 | anywhere predicate values are accepted: | |
| 99 | ||
| 100 | - :meth:`pyramid.config.Configurator.add_view` | |
| 101 | ||
| 102 | - :meth:`pyramid.config.Configurator.add_route` | |
| 103 | ||
| 104 | - :meth:`pyramid.config.Configurator.add_subscriber` | |
| 105 | ||
| 106 | - :meth:`pyramid.view.view_config` | |
| 107 | ||
| 108 | - :meth:`pyramid.events.subscriber` | |
| 109 | ||
| 110 | .. versionadded:: 1.5 | |
| 111 | """ | |
| 0c29cf | 112 | |
| 32333e | 113 | def __init__(self, value): |
| CM | 114 | self.value = value |
| 115 | ||
| 116 | ||
| fc3f23 | 117 | # under = after |
| CM | 118 | # over = before |
| a00621 | 119 | |
| 08422e | 120 | |
| 0c29cf | 121 | class PredicateList(object): |
| a00621 | 122 | def __init__(self): |
| CM | 123 | self.sorter = TopologicalSorter() |
| 9c8ec5 | 124 | self.last_added = None |
| a00621 | 125 | |
| CM | 126 | def add(self, name, factory, weighs_more_than=None, weighs_less_than=None): |
| 9c8ec5 | 127 | # Predicates should be added to a predicate list in (presumed) |
| CM | 128 | # computation expense order. |
| a54bc1 | 129 | # if weighs_more_than is None and weighs_less_than is None: |
| MM | 130 | # weighs_more_than = self.last_added or FIRST |
| 131 | # weighs_less_than = LAST | |
| 9c8ec5 | 132 | self.last_added = name |
| 0ccdc2 | 133 | self.sorter.add( |
| 0c29cf | 134 | name, factory, after=weighs_more_than, before=weighs_less_than |
| MM | 135 | ) |
| a00621 | 136 | |
| 51ee34 | 137 | def names(self): |
| BJR | 138 | # Return the list of valid predicate names. |
| 139 | return self.sorter.names | |
| 140 | ||
| 9c8ec5 | 141 | def make(self, config, **kw): |
| CM | 142 | # Given a configurator and a list of keywords, a predicate list is |
| 143 | # computed. Elsewhere in the code, we evaluate predicates using a | |
| 144 | # generator expression. All predicates associated with a view or | |
| 145 | # route must evaluate true for the view or route to "match" during a | |
| 146 | # request. The fastest predicate should be evaluated first, then the | |
| 147 | # next fastest, and so on, as if one returns false, the remainder of | |
| 148 | # the predicates won't need to be evaluated. | |
| 149 | # | |
| 150 | # While we compute predicates, we also compute a predicate hash (aka | |
| 151 | # phash) that can be used by a caller to identify identical predicate | |
| 152 | # lists. | |
| a00621 | 153 | ordered = self.sorter.sorted() |
| CM | 154 | phash = md5() |
| 155 | weights = [] | |
| 9c8ec5 | 156 | preds = [] |
| CM | 157 | for n, (name, predicate_factory) in enumerate(ordered): |
| a00621 | 158 | vals = kw.pop(name, None) |
| 0c29cf | 159 | if vals is None: # XXX should this be a sentinel other than None? |
| a00621 | 160 | continue |
| 9c8ec5 | 161 | if not isinstance(vals, predvalseq): |
| a00621 | 162 | vals = (vals,) |
| CM | 163 | for val in vals: |
| 32333e | 164 | realval = val |
| CM | 165 | notted = False |
| 166 | if isinstance(val, not_): | |
| 167 | realval = val.value | |
| 168 | notted = True | |
| 169 | pred = predicate_factory(realval, config) | |
| 170 | if notted: | |
| 171 | pred = Notted(pred) | |
| 9c8ec5 | 172 | hashes = pred.phash() |
| a00621 | 173 | if not is_nonstr_iter(hashes): |
| CM | 174 | hashes = [hashes] |
| 175 | for h in hashes: | |
| 176 | phash.update(bytes_(h)) | |
| 25c64c | 177 | weights.append(1 << n + 1) |
| 9c8ec5 | 178 | preds.append(pred) |
| a00621 | 179 | if kw: |
| 96dd80 | 180 | from difflib import get_close_matches |
| 0c29cf | 181 | |
| 08422e | 182 | closest = [] |
| 0c29cf | 183 | names = [name for name, _ in ordered] |
| 08422e | 184 | for name in kw: |
| FL | 185 | closest.extend(get_close_matches(name, names, 3)) |
| 186 | ||
| 187 | raise ConfigurationError( | |
| 188 | 'Unknown predicate values: %r (did you mean %s)' | |
| 189 | % (kw, ','.join(closest)) | |
| 190 | ) | |
| 9c8ec5 | 191 | # A "order" is computed for the predicate list. An order is |
| CM | 192 | # a scoring. |
| 193 | # | |
| 194 | # Each predicate is associated with a weight value. The weight of a | |
| 195 | # predicate symbolizes the relative potential "importance" of the | |
| 196 | # predicate to all other predicates. A larger weight indicates | |
| 197 | # greater importance. | |
| 198 | # | |
| 199 | # All weights for a given predicate list are bitwise ORed together | |
| 200 | # to create a "score"; this score is then subtracted from | |
| 201 | # MAX_ORDER and divided by an integer representing the number of | |
| 202 | # predicates+1 to determine the order. | |
| 203 | # | |
| 204 | # For views, the order represents the ordering in which a "multiview" | |
| 205 | # ( a collection of views that share the same context/request/name | |
| 206 | # triad but differ in other ways via predicates) will attempt to call | |
| 207 | # its set of views. Views with lower orders will be tried first. | |
| 208 | # The intent is to a) ensure that views with more predicates are | |
| 209 | # always evaluated before views with fewer predicates and b) to | |
| 210 | # ensure a stable call ordering of views that share the same number | |
| 211 | # of predicates. Views which do not have any predicates get an order | |
| 212 | # of MAX_ORDER, meaning that they will be tried very last. | |
| a00621 | 213 | score = 0 |
| CM | 214 | for bit in weights: |
| 215 | score = score | bit | |
| 9c8ec5 | 216 | order = (MAX_ORDER - score) / (len(preds) + 1) |
| CM | 217 | return order, preds, phash.hexdigest() |
| f2294f | 218 | |
| MM | 219 | |
| 19eef8 | 220 | def normalize_accept_offer(offer, allow_range=False): |
| MM | 221 | if allow_range and '*' in offer: |
| 222 | return offer.lower() | |
| 223 | return str(Accept.parse_offer(offer)) | |
| 4a9f4f | 224 | |
| MM | 225 | |
| f2294f | 226 | def sort_accept_offers(offers, order=None): |
| MM | 227 | """ |
| 4a9f4f | 228 | Sort a list of offers by preference. |
| f2294f | 229 | |
| 4a9f4f | 230 | For a given ``type/subtype`` category of offers, this algorithm will |
| MM | 231 | always sort offers with params higher than the bare offer. |
| f2294f | 232 | |
| MM | 233 | :param offers: A list of offers to be sorted. |
| 234 | :param order: A weighted list of offers where items closer to the start of | |
| 235 | the list will be a preferred over items closer to the end. | |
| 236 | :return: A list of offers sorted first by specificity (higher to lower) | |
| 237 | then by ``order``. | |
| 238 | ||
| 239 | """ | |
| 240 | if order is None: | |
| 241 | order = [] | |
| 242 | ||
| 243 | max_weight = len(offers) | |
| 244 | ||
| 245 | def find_order_index(value, default=None): | |
| 246 | return next((i for i, x in enumerate(order) if x == value), default) | |
| 247 | ||
| 248 | def offer_sort_key(value): | |
| 249 | """ | |
| 4a9f4f | 250 | (type_weight, params_weight) |
| f2294f | 251 | |
| MM | 252 | type_weight: |
| 4a9f4f | 253 | - index of specific ``type/subtype`` in order list |
| f2294f | 254 | - ``max_weight * 2`` if no match is found |
| MM | 255 | |
| 256 | params_weight: | |
| 257 | - index of specific ``type/subtype;params`` in order list | |
| 258 | - ``max_weight`` if not found | |
| 259 | - ``max_weight + 1`` if no params at all | |
| 260 | ||
| 261 | """ | |
| 262 | parsed = Accept.parse_offer(value) | |
| 263 | ||
| 4a9f4f | 264 | type_w = find_order_index( |
| 0c29cf | 265 | parsed.type + '/' + parsed.subtype, max_weight |
| 4a9f4f | 266 | ) |
| f2294f | 267 | |
| MM | 268 | if parsed.params: |
| 269 | param_w = find_order_index(value, max_weight) | |
| 270 | ||
| 271 | else: | |
| 272 | param_w = max_weight + 1 | |
| 273 | ||
| 4a9f4f | 274 | return (type_w, param_w) |
| f2294f | 275 | |
| MM | 276 | return sorted(offers, key=offer_sort_key) |
