Issues in triggers.py (master) - Issues in master - Natureshadow/OSMAlchemy - Measure and Improve Code Quality continuously with Scrutinizer

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osmalchemy/triggers.py (2 issues)

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# ~*~ 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 hashlib import md5
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(oa):
    """ Generates the triggers for online functionality.

      oa - reference to the OSMAlchemy instance to be configured
    """

    _visited_queries = WeakSet()

    @listens_for(oa.node, "load")
    @listens_for(oa.way, "load")
    @listens_for(oa.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

        # 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

        oa.logger.debug("Loading instance of type %s with id %i." % (type_, id_))

        # Check whether object needs to be refreshed
        updated = target.osmalchemy_updated
        timediff = datetime.datetime.now() - updated
        if timediff.total_seconds() < oa.maxage:
            oa.logger.debug("Instance is only %i seconds old, not refreshing online." % timediff.total_seconds())
            return

        oa.logger.debug("Refreshing instance online.")

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

        # 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(oa, xml, session=session)
        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)

        oa.logger.debug("Analysing new ORM query.")

        # Check whether this query affects our model
        affected_models = set([c["type"] for c in query.column_descriptions])
        our_models = set([oa.node, oa.way,  oa.relation,
                          oa.element])
        if affected_models.isdisjoint(our_models):
            # None of our models is affected
            oa.logger.debug("None of our models are 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
            oa.logger.debug("No filters found in query.")
            return

        oa.logger.debug("Building query tree from ORM query structure.")

        # 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:
            oa.logger.debug("No relevant query trees built.")
            return

        # Compile to OverpassQL
        oql = _trees_to_overpassql(trees)
        oa.logger.debug("Compiled OverpassQL: %s" % oql)

        # Look up query in cache
        hashed_oql = md5(_normalise_overpassql(oql).encode()).hexdigest()
        cached_query = session.query(oa.cached_query).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.total_seconds() < oa.maxage:
                # Return and do nothing if query was run recently
                oa.logger.debug("Query was run online only %i seconds ago, not running." % timediff.total_seconds())
                return

        # Run query online
        oa.logger.debug("Running Overpass query.")
        xml = _get_elements_by_query(oa.overpass, oql)

        # 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(oa, xml, session=session)
        del session._osmalchemy_in_trigger

        # Store or update query time
        if not cached_query:
            cached_query = oa.cached_query()
            cached_query.oql_hash = hashed_oql
        cached_query.oql_queried = datetime.datetime.now()
        session.add(cached_query)
        session.commit()
        oa.logger.debug("Query cached.")


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 hashlib import md5
33	1	from sqlalchemy import inspect
34	1	from sqlalchemy.event import listens_for
35		from sqlalchemy.orm import Query
36	1	from weakref import WeakSet
37	1
38		from .util.db import _import_osm_xml
39	1	from .util.online import (_get_elements_by_query, _where_to_tree,
40		_trees_to_overpassql, _normalise_overpassql,
41		_get_single_element_by_id)
42
43		def _generate_triggers(oa):
44		""" Generates the triggers for online functionality.
45
46		oa - reference to the OSMAlchemy instance to be configured
47		"""
48
49		_visited_queries = WeakSet()
50
51		@listens_for(oa.node, "load")
52		@listens_for(oa.way, "load")
53		@listens_for(oa.relation, "load")
54		def _instance_loading(target, context, _=None):
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		# Determine OSM element type and id
64		type_ = target.__class__.__name__[3:].lower()
65		id_ = target.id
66
67
68		# Guard against broken objects without an id
69		if id_ is None:
70		return
71
72		oa.logger.debug("Loading instance of type %s with id %i." % (type_, id_))
73
74		# Check whether object needs to be refreshed
75		updated = target.osmalchemy_updated
76		timediff = datetime.datetime.now() - updated
77		if timediff.total_seconds() < oa.maxage:
78		oa.logger.debug("Instance is only %i seconds old, not refreshing online." % timediff.total_seconds())
79		return
80
81		oa.logger.debug("Refreshing instance online.")
82
83		# Get object by id as XML
84		xml = _get_single_element_by_id(oa.overpass, type_, id_)
85
86		# Import data
87		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 Show Similar Issues like this 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...
88		_import_osm_xml(oa, xml, session=session)
89		del session._osmalchemy_in_trigger
90
91		@listens_for(Query, "before_compile")
92		def _query_compiling(query):
93		# Get the session associated with the query:
94		session = query.session
95
96		# Skip if the session was in a trigger before
97		# Prevents recursion in import code
98		if hasattr(session, "_osmalchemy_in_trigger"):
99		return
100
101		# Prevent recursion by skipping already-seen queries
102		if query in _visited_queries:
103		return
104		else:
105		_visited_queries.add(query)
106
107		oa.logger.debug("Analysing new ORM query.")
108
109		# Check whether this query affects our model
110		affected_models = set([c["type"] for c in query.column_descriptions])
111		our_models = set([oa.node, oa.way, oa.relation,
112		oa.element])
113		if affected_models.isdisjoint(our_models):
114		# None of our models is affected
115		oa.logger.debug("None of our models are affected.")
116		return
117
118		# Check whether this query filters elements
119		# Online update will only run on a specified set, not all data
120		if query.whereclause is None:
121		# No filters
122		oa.logger.debug("No filters found in query.")
123		return
124
125		oa.logger.debug("Building query tree from ORM query structure.")
126
127		# Analyse where clause looking for all looked-up fields
128		trees = {}
129		for target in our_models.intersection(affected_models):
130		# Build expression trees first
131		tree = _where_to_tree(query.whereclause, target)
132		if not tree is None:
133		trees[target.__name__] = tree
134
135		# Bail out if no relevant trees were built
136		if not trees:
137		oa.logger.debug("No relevant query trees built.")
138		return
139
140		# Compile to OverpassQL
141		oql = _trees_to_overpassql(trees)
142		oa.logger.debug("Compiled OverpassQL: %s" % oql)
143
144		# Look up query in cache
145		hashed_oql = md5(_normalise_overpassql(oql).encode()).hexdigest()
146		cached_query = session.query(oa.cached_query).filter_by(oql_hash=hashed_oql).scalar()
147		# Check age if cached query was found
148		if cached_query:
149		timediff = datetime.datetime.now() - cached_query.oql_queried
150		if timediff.total_seconds() < oa.maxage:
151		# Return and do nothing if query was run recently
152		oa.logger.debug("Query was run online only %i seconds ago, not running." % timediff.total_seconds())
153		return
154
155		# Run query online
156		oa.logger.debug("Running Overpass query.")
157		xml = _get_elements_by_query(oa.overpass, oql)
158
159		# Import data
160		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 Show Similar Issues like this 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...
161		_import_osm_xml(oa, xml, session=session)
162		del session._osmalchemy_in_trigger
163
164		# Store or update query time
165		if not cached_query:
166		cached_query = oa.cached_query()
167		cached_query.oql_hash = hashed_oql
168		cached_query.oql_queried = datetime.datetime.now()
169		session.add(cached_query)
170		session.commit()
171		oa.logger.debug("Query cached.")
172

Natureshadow / OSMAlchemy

Issues (77)

osmalchemy/triggers.py (2 issues)

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