_query_compiling() - Code Metrics - Inspection of "Guard trigger against recursion" - Natureshadow/OSMAlchemy - Measure and Improve Code Quality continuously with Scrutinizer

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Push — master ( da4639...75155f )

by Dominik

created 2016-08-10 20:51 UTC

_query_compiling() C

↳ Parent: _generate_triggers()

Complexity

Conditions

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	0
CRAP Score	56

Importance

Changes	7
Bugs	0	Features	0

Metric	Value
cc	7
c	7
b	0
f	0
dl	0
loc	45
ccs	0
cts	22
cp	0
crap	56
rs	5.5

# ~*~ coding: utf-8 ~*~
#-
# OSMAlchemy - OpenStreetMap to SQLAlchemy bridge
# Copyright (c) 2016 Dominik George <[email protected]>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#
# Alternatively, you are free to use OSMAlchemy under Simplified BSD, The
# MirOS Licence, GPL-2+, LGPL-2.1+, AGPL-3+ or the same terms as Python
# itself.

""" Trigger code for live OSMAlchemy/Overpass integration. """

import datetime

from sqlalchemy import inspect

from sqlalchemy.event import listens_for
from sqlalchemy.orm import Query
from weakref import WeakSet


from .util.db import _import_osm_xml
from .util.online import _get_elements_by_query, _where_to_tree, _trees_to_overpassql

def _generate_triggers(osmalchemy, maxage=60*60*24):

    """ Generates the triggers for online functionality.

      osmalchemy - reference to the OSMAlchemy instance to be configured
      maxage - maximum age of objects before they are updated online, in seconds
    """

    _visited_queries = WeakSet()

    @listens_for(Query, "before_compile")
    def _query_compiling(query):

        # Get the session associated with the query:
        session = query.session

        # Skip if the session was in a trigger before
        # Prevents recursion in import code
        if hasattr(session, "_osmalchemy_in_trigger"):
            return

        # Prevent recursion by skipping already-seen queries
        if query in _visited_queries:
            return
        else:
            _visited_queries.add(query)

        # Check whether this query affects our model
        affected_models = set([c["type"] for c in query.column_descriptions])
        our_models = set([osmalchemy.node, osmalchemy.way,  osmalchemy.relation,

                          osmalchemy.element])
        if affected_models.isdisjoint(our_models):
            # None of our models is affected
            return

        # Check whether this query filters elements
        # Online update will only run on a specified set, not all data
        if query.whereclause is None:
            # No filters
            return

        # Analyse where clause looking for all looked-up fields
        trees = {}
        for target in our_models.intersection(affected_models):
            # Build expression trees first
            trees[target.__name__] = _where_to_tree(query.whereclause, target)

        # Compile to OverpassQL and run query
        query = _trees_to_overpassql(trees)
        print(query)

        xml = _get_elements_by_query(osmalchemy._overpass, query)
class MyParent:
    def __init__(self):
        self._x = 1;
        self.y = 2;

class MyChild(MyParent):
    def some_method(self):
        return self._x    # Ok, since accessed from a child class

class AnotherClass:
    def some_method(self, instance_of_my_child):
        return instance_of_my_child._x   # Would be flagged as AnotherClass is not
                                         # a child class of MyParent

        # Import data
        session._osmalchemy_in_trigger = True
class MyParent:
    def __init__(self):
        self._x = 1;
        self.y = 2;

class MyChild(MyParent):
    def some_method(self):
        return self._x    # Ok, since accessed from a child class

class AnotherClass:
    def some_method(self, instance_of_my_child):
        return instance_of_my_child._x   # Would be flagged as AnotherClass is not
                                         # a child class of MyParent
        _import_osm_xml(osmalchemy, session, xml)
        del session._osmalchemy_in_trigger


1		# ~~ coding: utf-8 ~~
2		#-
3		# OSMAlchemy - OpenStreetMap to SQLAlchemy bridge
4		# Copyright (c) 2016 Dominik George <[email protected]>
5		#
6		# Permission is hereby granted, free of charge, to any person obtaining a copy
7		# of this software and associated documentation files (the "Software"), to deal
8		# in the Software without restriction, including without limitation the rights
9		# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10		# copies of the Software, and to permit persons to whom the Software is
11		# furnished to do so, subject to the following conditions:
12		#
13		# The above copyright notice and this permission notice shall be included in all
14		# copies or substantial portions of the Software.
15		#
16		# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17		# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18		# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19		# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20		# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21		# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22		# SOFTWARE.
23		#
24		# Alternatively, you are free to use OSMAlchemy under Simplified BSD, The
25		# MirOS Licence, GPL-2+, LGPL-2.1+, AGPL-3+ or the same terms as Python
26		# itself.
27
28	1	""" Trigger code for live OSMAlchemy/Overpass integration. """
29
30	1	import datetime
		0 ignored issues – show Unused Code introduced 2016-08-06 23:53 UTC by Report Bug Copy Issue Report The import `datetime` seems to be unused. Loading history...
31	1	from sqlalchemy import inspect
		0 ignored issues – show Unused Code introduced 2016-08-06 23:53 UTC by Report Bug Copy Issue Report Unused inspect imported from sqlalchemy Loading history...
32	1	from sqlalchemy.event import listens_for
33	1	from sqlalchemy.orm import Query
34	1	from weakref import WeakSet
		0 ignored issues – show introduced 2016-08-06 23:53 UTC by Report Bug Copy Issue Report standard import "from weakref import WeakSet" comes before "from sqlalchemy import inspect" Loading history...
35
36	1	from .util.db import _import_osm_xml
37	1	from .util.online import _get_elements_by_query, _where_to_tree, _trees_to_overpassql
38
39	1	def _generate_triggers(osmalchemy, maxage=606024):
		0 ignored issues – show Unused Code introduced 2016-08-06 23:53 UTC by Report Bug Copy Issue Report The argument `maxage` seems to be unused. Loading history...
40		""" Generates the triggers for online functionality.
41
42		osmalchemy - reference to the OSMAlchemy instance to be configured
43		maxage - maximum age of objects before they are updated online, in seconds
44		"""
45
46		_visited_queries = WeakSet()
47
48		@listens_for(Query, "before_compile")
49		def _query_compiling(query):
		0 ignored issues – show Unused Code introduced 2016-08-06 23:53 UTC by Report Bug Copy Issue Report The variable `_query_compiling` seems to be unused. Loading history...
50		# Get the session associated with the query:
51		session = query.session
52
53		# Skip if the session was in a trigger before
54		# Prevents recursion in import code
55		if hasattr(session, "_osmalchemy_in_trigger"):
56		return
57
58		# Prevent recursion by skipping already-seen queries
59		if query in _visited_queries:
60		return
61		else:
62		_visited_queries.add(query)
63
64		# Check whether this query affects our model
65		affected_models = set([c["type"] for c in query.column_descriptions])
66		our_models = set([osmalchemy.node, osmalchemy.way, osmalchemy.relation,
		0 ignored issues – show Coding Style introduced 2016-08-07 12:46 UTC by Report Bug Copy Issue Report Exactly one space required after comma Loading history...
67		osmalchemy.element])
68		if affected_models.isdisjoint(our_models):
69		# None of our models is affected
70		return
71
72		# Check whether this query filters elements
73		# Online update will only run on a specified set, not all data
74		if query.whereclause is None:
75		# No filters
76		return
77
78		# Analyse where clause looking for all looked-up fields
79		trees = {}
80		for target in our_models.intersection(affected_models):
81		# Build expression trees first
82		trees[target.__name__] = _where_to_tree(query.whereclause, target)
83
84		# Compile to OverpassQL and run query
85		query = _trees_to_overpassql(trees)
86		print(query)
		0 ignored issues – show Unused Code Coding Style introduced 2016-08-10 21:05 UTC by Report Bug Copy Issue Report Unnecessary parens after u'print' keyword Loading history...
87		xml = _get_elements_by_query(osmalchemy._overpass, query)
		0 ignored issues – show Coding Style Best Practice introduced 2016-08-10 21:05 UTC by Report Bug Copy Issue Report It seems like `_overpass` was declared protected and should not be accessed from this context. Prefixing a member variable `_` is usually regarded as the equivalent of declaring it with protected visibility that exists in other languages. Consequentially, such a member should only be accessed from the same class or a child class: class MyParent: def __init__(self): self._x = 1; self.y = 2; class MyChild(MyParent): def some_method(self): return self._x # Ok, since accessed from a child class class AnotherClass: def some_method(self, instance_of_my_child): return instance_of_my_child._x # Would be flagged as AnotherClass is not # a child class of MyParent Loading history...
88
89		# Import data
90		session._osmalchemy_in_trigger = True
		0 ignored issues – show Coding Style Best Practice introduced 2016-08-10 21:05 UTC by Report Bug Copy Issue Report It seems like `_osmalchemy_in_trigger` was declared protected and should not be accessed from this context. Prefixing a member variable `_` is usually regarded as the equivalent of declaring it with protected visibility that exists in other languages. Consequentially, such a member should only be accessed from the same class or a child class: class MyParent: def __init__(self): self._x = 1; self.y = 2; class MyChild(MyParent): def some_method(self): return self._x # Ok, since accessed from a child class class AnotherClass: def some_method(self, instance_of_my_child): return instance_of_my_child._x # Would be flagged as AnotherClass is not # a child class of MyParent Loading history...
91		_import_osm_xml(osmalchemy, session, xml)
92		del session._osmalchemy_in_trigger
93

Natureshadow / OSMAlchemy

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_query_compiling() C

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