_instance_loading() - Code Metrics - Inspection of "Add trigger for refreshing OSM elements on loading..." - Natureshadow/OSMAlchemy - Measure and Improve Code Quality continuously with Scrutinizer

Test Failed

Push — master ( 3849ae...191233 )

by Dominik

created 2016-09-08 18:49 UTC

_instance_loading() B

↳ Parent: _generate_triggers()

Complexity

Conditions

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	0
CRAP Score	20

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
cc	4
c	1
b	0
f	0
dl	0
loc	33
ccs	0
cts	15
cp	0
crap	20
rs	8.5806

# ~*~ coding: utf-8 ~*~
#-
# OSMAlchemy - OpenStreetMap to SQLAlchemy bridge
# Copyright (c) 2016 Dominik George <[email protected]>
# Copyright (c) 2016 Eike Tim Jesinghaus <[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, _normalise_overpassql,
                          _get_single_element_by_id)

def _generate_triggers(osmalchemy, osmcachedquery, 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(osmalchemy.node, "load")
    @listens_for(osmalchemy.way, "load")
    @listens_for(osmalchemy.relation, "load")
    def _instance_loading(target, context, _=None):

        # Get query session
        session = context.session

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

        # Check whether object needs to be refreshed
        updated = target.osmalchemy_updated
        timediff = datetime.datetime.now() - updated
        if timediff.total_seconds() < maxage:
            return

        # Determine OSM element type and id
        type_ = target.__class__.__name__[3:].lower()
        id_ = target.id

        # Guard against broken objects without an id
        if id_ is None:
            return

        # Get object by id as XML
        xml = _get_single_element_by_id(osmalchemy._overpass, type_, id_)
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

    @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
            tree = _where_to_tree(query.whereclause, target)
            if not tree is None:
                trees[target.__name__] = tree

        # Bail out if no relevant trees were built
        if not trees:
            return

        # Compile to OverpassQL
        oql = _trees_to_overpassql(trees)

        # Look up query in cache
        hashed_oql = hash(_normalise_overpassql(oql))
        cached_query = session.query(osmcachedquery).filter_by(oql_hash=hashed_oql).scalar()
        # Check age if cached query was found
        if cached_query:
            timediff = datetime.datetime.now() - cached_query.oql_queried
            if timediff.seconds < maxage:
                # Return and do nothing if query was run recently
                return

        # Run query online
        xml = _get_elements_by_query(osmalchemy._overpass, oql)
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

        # Store or update query time
        if not cached_query:
            cached_query = osmcachedquery()
            cached_query.oql_hash = hashed_oql
        cached_query.oql_queried = datetime.datetime.now()
        session.add(cached_query)
        session.commit()


1		# ~~ coding: utf-8 ~~
2		#-
3		# OSMAlchemy - OpenStreetMap to SQLAlchemy bridge
4		# Copyright (c) 2016 Dominik George <[email protected]>
5		# Copyright (c) 2016 Eike Tim Jesinghaus <[email protected]>
6		#
7		# Permission is hereby granted, free of charge, to any person obtaining a copy
8		# of this software and associated documentation files (the "Software"), to deal
9		# in the Software without restriction, including without limitation the rights
10		# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11		# copies of the Software, and to permit persons to whom the Software is
12		# furnished to do so, subject to the following conditions:
13		#
14		# The above copyright notice and this permission notice shall be included in all
15		# copies or substantial portions of the Software.
16		#
17		# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18		# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19		# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20		# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21		# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22		# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23		# SOFTWARE.
24		#
25		# Alternatively, you are free to use OSMAlchemy under Simplified BSD, The
26		# MirOS Licence, GPL-2+, LGPL-2.1+, AGPL-3+ or the same terms as Python
27		# itself.
28	1
29		""" Trigger code for live OSMAlchemy/Overpass integration. """
30	1
31	1	import datetime
32	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...
33	1	from sqlalchemy.event import listens_for
34	1	from sqlalchemy.orm import Query
35		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...
36	1
37	1	from .util.db import _import_osm_xml
38		from .util.online import (_get_elements_by_query, _where_to_tree,
39	1	_trees_to_overpassql, _normalise_overpassql,
40		_get_single_element_by_id)
41
42		def _generate_triggers(osmalchemy, osmcachedquery, maxage=606024):
43		""" Generates the triggers for online functionality.
44
45		osmalchemy - reference to the OSMAlchemy instance to be configured
46		maxage - maximum age of objects before they are updated online, in seconds
47		"""
48
49		_visited_queries = WeakSet()
50
51		@listens_for(osmalchemy.node, "load")
52		@listens_for(osmalchemy.way, "load")
53		@listens_for(osmalchemy.relation, "load")
54		def _instance_loading(target, context, _=None):
		0 ignored issues – show Unused Code introduced 2016-09-08 18:56 UTC by Report Bug Copy Issue Report The variable `_instance_loading` seems to be unused. Loading history...
55		# Get query session
56		session = context.session
57
58		# Skip if the session was in a trigger before
59		# Prevents recursion in import code
60		if hasattr(session, "_osmalchemy_in_trigger"):
61		return
62
63		# Check whether object needs to be refreshed
64		updated = target.osmalchemy_updated
65		timediff = datetime.datetime.now() - updated
66		if timediff.total_seconds() < maxage:
67		return
68
69		# Determine OSM element type and id
70		type_ = target.__class__.__name__[3:].lower()
71		id_ = target.id
72
73		# Guard against broken objects without an id
74		if id_ is None:
75		return
76
77		# Get object by id as XML
78		xml = _get_single_element_by_id(osmalchemy._overpass, type_, id_)
		0 ignored issues – show Coding Style Best Practice introduced 2016-09-08 18:56 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...
79
80		# Import data
81		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...
82		_import_osm_xml(osmalchemy, session, xml)
83		del session._osmalchemy_in_trigger
84
85		@listens_for(Query, "before_compile")
86		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...
87		# Get the session associated with the query:
88		session = query.session
89
90		# Skip if the session was in a trigger before
91		# Prevents recursion in import code
92		if hasattr(session, "_osmalchemy_in_trigger"):
93		return
94
95		# Prevent recursion by skipping already-seen queries
96		if query in _visited_queries:
97		return
98		else:
99		_visited_queries.add(query)
100
101		# Check whether this query affects our model
102		affected_models = set([c["type"] for c in query.column_descriptions])
103		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...
104		osmalchemy.element])
105		if affected_models.isdisjoint(our_models):
106		# None of our models is affected
107		return
108
109		# Check whether this query filters elements
110		# Online update will only run on a specified set, not all data
111		if query.whereclause is None:
112		# No filters
113		return
114
115		# Analyse where clause looking for all looked-up fields
116		trees = {}
117		for target in our_models.intersection(affected_models):
118		# Build expression trees first
119		tree = _where_to_tree(query.whereclause, target)
120		if not tree is None:
121		trees[target.__name__] = tree
122
123		# Bail out if no relevant trees were built
124		if not trees:
125		return
126
127		# Compile to OverpassQL
128		oql = _trees_to_overpassql(trees)
129
130		# Look up query in cache
131		hashed_oql = hash(_normalise_overpassql(oql))
132		cached_query = session.query(osmcachedquery).filter_by(oql_hash=hashed_oql).scalar()
133		# Check age if cached query was found
134		if cached_query:
135		timediff = datetime.datetime.now() - cached_query.oql_queried
136		if timediff.seconds < maxage:
137		# Return and do nothing if query was run recently
138		return
139
140		# Run query online
141		xml = _get_elements_by_query(osmalchemy._overpass, oql)
		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...
142
143		# Import data
144		session._osmalchemy_in_trigger = True
		0 ignored issues – show Coding Style Best Practice introduced 2016-09-08 18:56 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...
145		_import_osm_xml(osmalchemy, session, xml)
146		del session._osmalchemy_in_trigger
147
148		# Store or update query time
149		if not cached_query:
150		cached_query = osmcachedquery()
151		cached_query.oql_hash = hashed_oql
152		cached_query.oql_queried = datetime.datetime.now()
153		session.add(cached_query)
154		session.commit()
155

Natureshadow / OSMAlchemy

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