387 lines
11 KiB
Python
387 lines
11 KiB
Python
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"""
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uritemplate.variable
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====================
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This module contains the URIVariable class which powers the URITemplate class.
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What treasures await you:
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- URIVariable class
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You see a hammer in front of you.
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What do you do?
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>
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"""
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import sys
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try:
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import collections.abc as collections_abc
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except ImportError:
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import collections as collections_abc
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if sys.version_info.major == 2:
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import urllib
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elif sys.version_info.major == 3:
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import urllib.parse as urllib
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class URIVariable(object):
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"""This object validates everything inside the URITemplate object.
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It validates template expansions and will truncate length as decided by
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the template.
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Please note that just like the :class:`URITemplate <URITemplate>`, this
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object's ``__str__`` and ``__repr__`` methods do not return the same
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information. Calling ``str(var)`` will return the original variable.
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This object does the majority of the heavy lifting. The ``URITemplate``
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object finds the variables in the URI and then creates ``URIVariable``
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objects. Expansions of the URI are handled by each ``URIVariable``
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object. ``URIVariable.expand()`` returns a dictionary of the original
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variable and the expanded value. Check that method's documentation for
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more information.
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"""
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operators = ('+', '#', '.', '/', ';', '?', '&', '|', '!', '@')
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reserved = ":/?#[]@!$&'()*+,;="
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def __init__(self, var):
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#: The original string that comes through with the variable
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self.original = var
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#: The operator for the variable
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self.operator = ''
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#: List of safe characters when quoting the string
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self.safe = ''
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#: List of variables in this variable
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self.variables = []
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#: List of variable names
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self.variable_names = []
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#: List of defaults passed in
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self.defaults = {}
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# Parse the variable itself.
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self.parse()
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self.post_parse()
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def __repr__(self):
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return 'URIVariable(%s)' % self
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def __str__(self):
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return self.original
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def parse(self):
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"""Parse the variable.
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This finds the:
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- operator,
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- set of safe characters,
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- variables, and
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- defaults.
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"""
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var_list = self.original
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if self.original[0] in URIVariable.operators:
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self.operator = self.original[0]
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var_list = self.original[1:]
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if self.operator in URIVariable.operators[:2]:
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self.safe = URIVariable.reserved
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var_list = var_list.split(',')
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for var in var_list:
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default_val = None
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name = var
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if '=' in var:
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name, default_val = tuple(var.split('=', 1))
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explode = False
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if name.endswith('*'):
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explode = True
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name = name[:-1]
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prefix = None
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if ':' in name:
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name, prefix = tuple(name.split(':', 1))
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prefix = int(prefix)
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if default_val:
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self.defaults[name] = default_val
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self.variables.append(
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(name, {'explode': explode, 'prefix': prefix})
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)
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self.variable_names = [varname for (varname, _) in self.variables]
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def post_parse(self):
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"""Set ``start``, ``join_str`` and ``safe`` attributes.
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After parsing the variable, we need to set up these attributes and it
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only makes sense to do it in a more easily testable way.
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"""
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self.safe = ''
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self.start = self.join_str = self.operator
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if self.operator == '+':
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self.start = ''
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if self.operator in ('+', '#', ''):
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self.join_str = ','
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if self.operator == '#':
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self.start = '#'
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if self.operator == '?':
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self.start = '?'
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self.join_str = '&'
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if self.operator in ('+', '#'):
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self.safe = URIVariable.reserved
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def _query_expansion(self, name, value, explode, prefix):
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"""Expansion method for the '?' and '&' operators."""
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if value is None:
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return None
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tuples, items = is_list_of_tuples(value)
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safe = self.safe
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if list_test(value) and not tuples:
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if not value:
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return None
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if explode:
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return self.join_str.join(
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'{}={}'.format(name, quote(v, safe)) for v in value
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)
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else:
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value = ','.join(quote(v, safe) for v in value)
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return '{}={}'.format(name, value)
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if dict_test(value) or tuples:
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if not value:
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return None
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items = items or sorted(value.items())
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if explode:
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return self.join_str.join(
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'{}={}'.format(
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quote(k, safe), quote(v, safe)
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) for k, v in items
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)
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else:
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value = ','.join(
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'{},{}'.format(
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quote(k, safe), quote(v, safe)
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) for k, v in items
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)
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return '{}={}'.format(name, value)
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if value:
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value = value[:prefix] if prefix else value
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return '{}={}'.format(name, quote(value, safe))
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return name + '='
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def _label_path_expansion(self, name, value, explode, prefix):
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"""Label and path expansion method.
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Expands for operators: '/', '.'
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"""
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join_str = self.join_str
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safe = self.safe
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if value is None or (len(value) == 0 and value != ''):
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return None
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tuples, items = is_list_of_tuples(value)
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if list_test(value) and not tuples:
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if not explode:
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join_str = ','
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fragments = [quote(v, safe) for v in value if v is not None]
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return join_str.join(fragments) if fragments else None
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if dict_test(value) or tuples:
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items = items or sorted(value.items())
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format_str = '%s=%s'
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if not explode:
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format_str = '%s,%s'
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join_str = ','
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expanded = join_str.join(
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format_str % (
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quote(k, safe), quote(v, safe)
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) for k, v in items if v is not None
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)
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return expanded if expanded else None
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value = value[:prefix] if prefix else value
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return quote(value, safe)
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def _semi_path_expansion(self, name, value, explode, prefix):
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"""Expansion method for ';' operator."""
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join_str = self.join_str
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safe = self.safe
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if value is None:
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return None
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if self.operator == '?':
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join_str = '&'
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tuples, items = is_list_of_tuples(value)
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if list_test(value) and not tuples:
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if explode:
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expanded = join_str.join(
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'{}={}'.format(
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name, quote(v, safe)
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) for v in value if v is not None
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)
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return expanded if expanded else None
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else:
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value = ','.join(quote(v, safe) for v in value)
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return '{}={}'.format(name, value)
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if dict_test(value) or tuples:
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items = items or sorted(value.items())
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if explode:
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return join_str.join(
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'{}={}'.format(
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quote(k, safe), quote(v, safe)
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) for k, v in items if v is not None
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)
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else:
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expanded = ','.join(
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'{},{}'.format(
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quote(k, safe), quote(v, safe)
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) for k, v in items if v is not None
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)
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return '{}={}'.format(name, expanded)
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value = value[:prefix] if prefix else value
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if value:
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return '{}={}'.format(name, quote(value, safe))
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return name
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def _string_expansion(self, name, value, explode, prefix):
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if value is None:
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return None
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tuples, items = is_list_of_tuples(value)
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if list_test(value) and not tuples:
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return ','.join(quote(v, self.safe) for v in value)
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if dict_test(value) or tuples:
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items = items or sorted(value.items())
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format_str = '%s=%s' if explode else '%s,%s'
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return ','.join(
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format_str % (
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quote(k, self.safe), quote(v, self.safe)
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) for k, v in items
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)
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value = value[:prefix] if prefix else value
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return quote(value, self.safe)
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def expand(self, var_dict=None):
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"""Expand the variable in question.
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Using ``var_dict`` and the previously parsed defaults, expand this
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variable and subvariables.
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:param dict var_dict: dictionary of key-value pairs to be used during
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expansion
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:returns: dict(variable=value)
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Examples::
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# (1)
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v = URIVariable('/var')
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expansion = v.expand({'var': 'value'})
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print(expansion)
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# => {'/var': '/value'}
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# (2)
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v = URIVariable('?var,hello,x,y')
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expansion = v.expand({'var': 'value', 'hello': 'Hello World!',
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'x': '1024', 'y': '768'})
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print(expansion)
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# => {'?var,hello,x,y':
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# '?var=value&hello=Hello%20World%21&x=1024&y=768'}
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"""
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return_values = []
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for name, opts in self.variables:
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value = var_dict.get(name, None)
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if not value and value != '' and name in self.defaults:
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value = self.defaults[name]
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if value is None:
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continue
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expanded = None
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if self.operator in ('/', '.'):
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expansion = self._label_path_expansion
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elif self.operator in ('?', '&'):
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expansion = self._query_expansion
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elif self.operator == ';':
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expansion = self._semi_path_expansion
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else:
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expansion = self._string_expansion
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expanded = expansion(name, value, opts['explode'], opts['prefix'])
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if expanded is not None:
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return_values.append(expanded)
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value = ''
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if return_values:
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value = self.start + self.join_str.join(return_values)
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return {self.original: value}
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def is_list_of_tuples(value):
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if (not value or
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not isinstance(value, (list, tuple)) or
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not all(isinstance(t, tuple) and len(t) == 2 for t in value)):
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return False, None
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return True, value
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def list_test(value):
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return isinstance(value, (list, tuple))
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def dict_test(value):
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return isinstance(value, (dict, collections_abc.MutableMapping))
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try:
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texttype = unicode
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except NameError: # Python 3
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texttype = str
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stringlikes = (texttype, bytes)
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def _encode(value, encoding='utf-8'):
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if (isinstance(value, texttype) and
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getattr(value, 'encode', None) is not None):
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return value.encode(encoding)
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return value
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def quote(value, safe):
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if not isinstance(value, stringlikes):
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value = str(value)
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return urllib.quote(_encode(value), safe)
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