_instance_loading() - Code Metrics - Natureshadow/OSMAlchemy - Measure and Improve Code Quality continuously with Scrutinizer

_instance_loading() B
last analyzed 2016-09-16 10:27 UTC

↳ Parent: _generate_triggers()

Complexity

Conditions

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	0
CRAP Score	20

Importance

Changes	2
Bugs	0	Features	0

Metric	Value
cc	4
c	2
b	0
f	0
dl	0
loc	39
ccs	0
cts	18
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 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
		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...
34	1	from sqlalchemy.event import listens_for
35		from sqlalchemy.orm import Query
36	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...
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):
		0 ignored issues – show Coding Style Naming introduced 2016-09-09 12:38 UTC by Report Bug Copy Issue Report The name `oa` does not conform to the argument naming conventions (`[a-z_][a-z0-9_]{2,30}$`). This check looks for invalid names for a range of different identifiers. You can set regular expressions to which the identifiers must conform if the defaults do not match your requirements. If your project includes a Pylint configuration file, the settings contained in that file take precedence. To find out more about Pylint, please refer to their site. Loading history...
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):
		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		# 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())
		0 ignored issues – show Coding Style introduced 2016-09-09 12:38 UTC by Report Bug Copy Issue Report This line is too long as per the coding-style (113/100). This check looks for lines that are too long. You can specify the maximum line length. Loading history...
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 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):
		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...
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,
		0 ignored issues – show Coding Style introduced 2016-09-09 12:38 UTC by Report Bug Copy Issue Report Exactly one space required after comma Loading history...
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())
		0 ignored issues – show Coding Style introduced 2016-09-09 12:38 UTC by Report Bug Copy Issue Report This line is too long as per the coding-style (116/100). This check looks for lines that are too long. You can specify the maximum line length. Loading history...
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 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

_instance_loading() B last analyzed 2016-09-16 10:27 UTC

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_instance_loading() B
last analyzed 2016-09-16 10:27 UTC