Introduce dynamic scope_path regexps
Instead of relying on scope_path's being "one slash deep", we should
instead allow for either:
1. scope_paths that have a pre-defined depth
2. scope_paths that can be arbitrarily deep
We achieve 1 by setting an entities scope_logic to another logic
module. We then recursively call getScopeDepth until we get to the
topmost entity (that is, an unscoped entity).
A little different is the solution to 2, since some entities can have
an arbitrarily deep scope (such as Documents), we need to have some
way of signaling this to getScopePattern. A clean solution is to
return None, rather than a number. If None is returned, the
SCOPE_PATH_ARG_PATTERN is returned as regexp instead, which will
match an arbitrarily deeply nested scope.
The solution for 2 requires that we return None somewhere in the
scope_logic chain, the most straight forward method to do so is to
override getScopeDepth anywhere such a scope is needed and make it
return None. A more elegant solution however, is to set the
scope_logic to that module in all entities that require it.
Patch by: Sverre Rabbelier
"""
This object provides quoting for GEOS geometries into PostgreSQL/PostGIS.
"""
from django.contrib.gis.db.backend.postgis.query import GEOM_FROM_WKB
from psycopg2 import Binary
from psycopg2.extensions import ISQLQuote
class PostGISAdaptor(object):
def __init__(self, geom):
"Initializes on the geometry."
# Getting the WKB (in string form, to allow easy pickling of
# the adaptor) and the SRID from the geometry.
self.wkb = str(geom.wkb)
self.srid = geom.srid
def __conform__(self, proto):
# Does the given protocol conform to what Psycopg2 expects?
if proto == ISQLQuote:
return self
else:
raise Exception('Error implementing psycopg2 protocol. Is psycopg2 installed?')
def __eq__(self, other):
return (self.wkb == other.wkb) and (self.srid == other.srid)
def __str__(self):
return self.getquoted()
def getquoted(self):
"Returns a properly quoted string for use in PostgreSQL/PostGIS."
# Want to use WKB, so wrap with psycopg2 Binary() to quote properly.
return "%s(%s, %s)" % (GEOM_FROM_WKB, Binary(self.wkb), self.srid or -1)