Source code for cubicweb.entity

# copyright 2003-2016 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact https://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb is free software: you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option)
# any later version.
#
# CubicWeb is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with CubicWeb.  If not, see <https://www.gnu.org/licenses/>.
"""Base class for entity objects manipulated in clients"""

from cubicweb import set_log_methods
from logging import getLogger
from logilab.common.decorators import cached
from logilab.common.registry import yes
from logilab.mtconverter import TransformData, xml_escape

from rql.utils import rqlvar_maker
from rql.stmts import Select
from rql.nodes import Not, VariableRef, Constant, make_relation, Relation as RqlRelation

from cubicweb import Unauthorized, neg_role
from cubicweb.utils import support_args
from cubicweb.rset import ResultSet
from cubicweb.appobject import AppObject
from cubicweb.schema import RQLVocabularyConstraint, RQLConstraint, GeneratedConstraint
from cubicweb.rqlrewrite import RQLRewriter

from cubicweb.uilib import soup2xhtml
from cubicweb.mttransforms import ENGINE

_marker = object()


def greater_card(rschema, subjtypes, objtypes, index):
    for subjtype in subjtypes:
        for objtype in objtypes:
            card = rschema.rdef(subjtype, objtype).cardinality[index]
            if card in "+*":
                return card
    return "1"


def can_use_rest_path(value):
    """return True if value can be used at the end of a Rest URL path"""
    if value is None:
        return False
    # the check for ?, /, & are to prevent problems when running
    # behind Apache mod_proxy
    if value == "" or "?" in value or "/" in value or "&" in value:
        return False
    return True


def rel_vars(rel):
    return (
        (isinstance(rel.children[0], VariableRef) and rel.children[0].variable or None),
        (
            isinstance(rel.children[1].children[0], VariableRef)
            and rel.children[1].children[0].variable
            or None
        ),
    )


def rel_matches(rel, rtype, role, varname, operator="="):
    if rel.r_type == rtype and rel.children[1].operator == operator:
        same_role_var_idx = 0 if role == "subject" else 1
        variables = rel_vars(rel)
        if variables[same_role_var_idx].name == varname:
            return variables[1 - same_role_var_idx]


def build_cstr_with_linkto_infos(cstr, args, searchedvar, evar, lt_infos, eidvars):
    """restrict vocabulary as much as possible in entity creation,
    based on infos provided by __linkto form param.

    Example based on following schema:

      class works_in(RelationDefinition):
          subject = 'CWUser'
          object = 'Lab'
          cardinality = '1*'
          constraints = [RQLConstraint('S in_group G, O welcomes G')]

      class welcomes(RelationDefinition):
          subject = 'Lab'
          object = 'CWGroup'

    If you create a CWUser in the "scientists" CWGroup you can show
    only the labs that welcome them using :

      lt_infos = {('in_group', 'subject'): 321}

    You get following restriction : 'O welcomes G, G eid 321'

    """
    st = cstr.snippet_rqlst.copy()
    # replace relations in ST by eid infos from linkto where possible
    for (info_rtype, info_role), eids in lt_infos.items():
        eid = eids[0]  # NOTE: we currently assume a pruned lt_info with only 1 eid
        for rel in st.iget_nodes(RqlRelation):
            targetvar = rel_matches(rel, info_rtype, info_role, evar.name)
            if targetvar is not None:
                if targetvar.name in eidvars:
                    rel.parent.remove(rel)
                else:
                    eidrel = make_relation(
                        targetvar, "eid", (targetvar.name, "Substitute"), Constant
                    )
                    rel.parent.replace(rel, eidrel)
                    args[targetvar.name] = eid
                    eidvars.add(targetvar.name)
    # if modified ST still contains evar references we must discard the
    # constraint, otherwise evar is unknown in the final rql query which can
    # lead to a SQL table cartesian product and multiple occurences of solutions
    evarname = evar.name
    for rel in st.iget_nodes(RqlRelation):
        for variable in rel_vars(rel):
            if variable and evarname == variable.name:
                return
    # else insert snippets into the global tree
    return GeneratedConstraint(st, cstr.mainvars - set(evarname))


def pruned_lt_info(eschema, lt_infos):
    pruned = {}
    for (lt_rtype, lt_role), eids in lt_infos.items():
        # we can only use lt_infos describing relation with a cardinality
        # of value 1 towards the linked entity
        if not len(eids) == 1:
            continue
        lt_card = eschema.rdef(lt_rtype, lt_role).cardinality[
            0 if lt_role == "subject" else 1
        ]
        if lt_card not in "?1":
            continue
        pruned[(lt_rtype, lt_role)] = eids
    return pruned


class Entity(AppObject):
    """an entity instance has e_schema automagically set on
    the class and instances has access to their issuing cursor.

    A property is set for each attribute and relation on each entity's type
    class. Becare that among attributes, 'eid' is *NEVER* stored in the
    dict containment (which acts as a cache for other attributes dynamically
    fetched)

    :type e_schema: `cubicweb.schema.EntitySchema`
    :ivar e_schema: the entity's schema

    :type rest_attr: str
    :cvar rest_attr: indicates which attribute should be used to build REST urls
       If `None` is specified (the default), the first unique attribute will
       be used ('eid' if none found)

    :type cw_skip_copy_for: list
    :cvar cw_skip_copy_for: a list of couples (rtype, role) for each relation
       that should be skipped when copying this kind of entity. Note that some
       relations such as composite relations or relations that have '?1' as
       object cardinality are always skipped.
    """

    __registry__ = "etypes"
    __select__ = yes()

    # class attributes that must be set in class definition
    rest_attr = None
    fetch_attrs = None
    cw_skip_copy_for = [("in_state", "subject")]
    # class attributes set automatically at registration time
    e_schema = None

    @classmethod
    def __initialize__(cls, schema):
        """initialize a specific entity class by adding descriptors to access
        entity type's attributes and relations
        """
        etype = cls.__regid__
        assert etype != "Any", etype
        cls.e_schema = eschema = schema.eschema(etype)
        for rschema, _ in eschema.attribute_definitions():
            if rschema.type == "eid":
                continue
            setattr(cls, rschema.type, Attribute(rschema.type))
        mixins = []
        for rschema, _, role in eschema.relation_definitions():
            if role == "subject":
                attr = rschema.type
            else:
                attr = "reverse_%s" % rschema.type
            setattr(cls, attr, Relation(rschema, role))

    fetch_attrs = ("modification_date",)

[docs] @classmethod def cw_fetch_order(cls, select, attr, var): """This class method may be used to control sort order when multiple entities of this type are fetched through ORM methods. Its arguments are: * `select`, the RQL syntax tree * `attr`, the attribute being watched * `var`, the variable through which this attribute's value may be accessed in the query When you want to do some sorting on the given attribute, you should modify the syntax tree accordingly. For instance: .. sourcecode:: python from rql import nodes class Version(AnyEntity): __regid__ = 'Version' fetch_attrs = ('num', 'description', 'in_state') @classmethod def cw_fetch_order(cls, select, attr, var): if attr == 'num': func = nodes.Function('version_sort_value') func.append(nodes.variable_ref(var)) sterm = nodes.SortTerm(func, asc=False) select.add_sort_term(sterm) The default implementation call :meth:`~cubicweb.entity.Entity.cw_fetch_unrelated_order` """ cls.cw_fetch_unrelated_order(select, attr, var)
[docs] @classmethod def cw_fetch_unrelated_order(cls, select, attr, var): """This class method may be used to control sort order when multiple entities of this type are fetched to use in edition (e.g. propose them to create a new relation on an edited entity). See :meth:`~cubicweb.entity.Entity.cw_fetch_unrelated_order` for a description of its arguments and usage. By default entities will be listed on their modification date descending, i.e. you'll get entities recently modified first. """ if attr == "modification_date": select.add_sort_var(var, asc=False)
@classmethod def fetch_rql( cls, user, fetchattrs=None, mainvar="X", settype=True, ordermethod="fetch_order" ): st = cls.fetch_rqlst( user, mainvar=mainvar, fetchattrs=fetchattrs, settype=settype, ordermethod=ordermethod, ) return st.as_string() @classmethod def fetch_rqlst( cls, user, select=None, mainvar="X", fetchattrs=None, settype=True, ordermethod="fetch_order", ): if select is None: select = Select() mainvar = select.get_variable(mainvar) select.add_selected(mainvar) elif isinstance(mainvar, str): assert mainvar in select.defined_vars mainvar = select.get_variable(mainvar) # eases string -> syntax tree test transition: please remove once stable select._varmaker = rqlvar_maker( defined=select.defined_vars, aliases=select.aliases, index=26 ) if settype: rel = select.add_type_restriction(mainvar, cls.__regid__) # should use 'is_instance_of' instead of 'is' so we retrieve # subclasses instances as well rel.r_type = "is_instance_of" if fetchattrs is None: fetchattrs = cls.fetch_attrs cls._fetch_restrictions(mainvar, select, fetchattrs, user, ordermethod) return select @classmethod def _fetch_ambiguous_rtypes(cls, select, var, fetchattrs, subjtypes, schema): """find rtypes in `fetchattrs` that relate different subject etypes taken from (`subjtypes`) to different target etypes; these so called "ambiguous" relations, are added directly to the `select` syntax tree selection but removed from `fetchattrs` to avoid the fetch recursion because we have to choose only one targettype for the recursion and adding its own fetch attrs to the selection -when we recurse- would filter out the other possible target types from the result set """ for attr in fetchattrs.copy(): rschema = schema.rschema(attr) if rschema.final: continue ttypes = None for subjtype in subjtypes: cur_ttypes = set(rschema.objects(subjtype)) if ttypes is None: ttypes = cur_ttypes elif cur_ttypes != ttypes: # we found an ambiguous relation: remove it from fetchattrs fetchattrs.remove(attr) # ... and add it to the selection targetvar = select.make_variable() select.add_selected(targetvar) rel = make_relation(var, attr, (targetvar,), VariableRef) select.add_restriction(rel) break @classmethod def _fetch_restrictions( cls, mainvar, select, fetchattrs, user, ordermethod="fetch_order", visited=None ): eschema = cls.e_schema if visited is None: visited = set((eschema.type,)) elif eschema.type in visited: # avoid infinite recursion return else: visited.add(eschema.type) for attr in sorted(fetchattrs): try: rschema = eschema.subjrels[attr] except KeyError: cls.warning( "skipping fetch_attr %s defined in %s (not found in schema)", attr, cls.__regid__, ) continue # XXX takefirst=True to remove warning triggered by ambiguous inlined relations rdef = eschema.rdef(attr, takefirst=True) if not user.matching_groups(rdef.get_groups("read")): continue if rschema.final or rdef.cardinality[0] in "?1": var = select.make_variable() select.add_selected(var) rel = make_relation(mainvar, attr, (var,), VariableRef) select.add_restriction(rel) else: cls.warning( "bad relation %s specified in fetch attrs for %s", attr, cls ) continue if not rschema.final: # XXX we need outer join in case the relation is not mandatory # (card == '?') *or if the entity is being added*, since in # that case the relation may still be missing. As we miss this # later information here, systematically add it. rel.change_optional("right") targettypes = rschema.objects(eschema.type) vreg = user._cw.vreg # XXX user._cw.vreg iiiirk etypecls = vreg["etypes"].etype_class(targettypes[0]) if len(targettypes) > 1: # find fetch_attrs common to all destination types fetchattrs = vreg["etypes"].fetch_attrs(targettypes) # ... and handle ambiguous relations cls._fetch_ambiguous_rtypes( select, var, fetchattrs, targettypes, vreg.schema ) else: fetchattrs = etypecls.fetch_attrs etypecls._fetch_restrictions( var, select, fetchattrs, user, None, visited=visited ) if ordermethod is not None: cmeth = getattr(cls, "cw_" + ordermethod) cmeth(select, attr, var) @classmethod @cached def cw_rest_attr_info(cls): """this class method return an attribute name to be used in URL for entities of this type and a boolean flag telling if its value should be checked for uniqness. The attribute returned is, in order of priority: * class's `rest_attr` class attribute * an attribute defined as unique in the class'schema * 'eid' """ mainattr, needcheck = "eid", True if cls.rest_attr: mainattr = cls.rest_attr needcheck = not cls.e_schema.has_unique_values(mainattr) else: for rschema in cls.e_schema.subject_relations(): if ( rschema.final and rschema not in ("eid", "cwuri") and cls.e_schema.has_unique_values(rschema) and cls.e_schema.rdef(rschema.type).cardinality[0] == "1" ): mainattr = str(rschema) needcheck = False break if mainattr == "eid": needcheck = False return mainattr, needcheck @classmethod def _cw_build_entity_query(cls, kwargs): relations = [] restrictions = set() pendingrels = [] eschema = cls.e_schema qargs = {} attrcache = {} for attr, value in kwargs.items(): if attr.startswith("reverse_"): attr = attr[len("reverse_") :] role = "object" else: role = "subject" assert eschema.has_relation(attr, role), "%s %s not found on %s" % ( attr, role, eschema, ) rschema = ( eschema.subjrels[attr] if role == "subject" else eschema.objrels[attr] ) if not rschema.final and isinstance(value, (tuple, list, set, frozenset)): if len(value) == 0: continue # avoid crash with empty IN clause elif len(value) == 1: value = next(iter(value)) else: # prepare IN clause pendingrels.append((attr, role, value)) continue if rschema.final: # attribute relations.append("X %s %%(%s)s" % (attr, attr)) attrcache[attr] = value elif value is None: pendingrels.append((attr, role, value)) else: rvar = attr.upper() if role == "object": relations.append("%s %s X" % (rvar, attr)) else: relations.append("X %s %s" % (attr, rvar)) restriction = "%s eid %%(%s)s" % (rvar, attr) if not restriction in restrictions: restrictions.add(restriction) if hasattr(value, "eid"): value = value.eid qargs[attr] = value rql = "" if relations: rql += ", ".join(relations) if restrictions: rql += " WHERE %s" % ", ".join(restrictions) return rql, qargs, pendingrels, attrcache @classmethod def _cw_handle_pending_relations(cls, eid, pendingrels, execute): for attr, role, values in pendingrels: if role == "object": restr = "Y %s X" % attr else: restr = "X %s Y" % attr if values is None: execute("DELETE %s WHERE X eid %%(x)s" % restr, {"x": eid}) continue execute( "SET %s WHERE X eid %%(x)s, Y eid IN (%s)" % (restr, ",".join(str(getattr(r, "eid", r)) for r in values)), {"x": eid}, build_descr=False, ) @classmethod def cw_instantiate(cls, execute, **kwargs): """add a new entity of this given type Example (in a shell session): >>> companycls = vreg['etypes'].etype_class('Company') >>> personcls = vreg['etypes'].etype_class('Person') >>> c = companycls.cw_instantiate(session.execute, name=u'Logilab') >>> p = personcls.cw_instantiate(session.execute, firstname=u'John', lastname=u'Doe', ... works_for=c) You can also set relations where the entity has 'object' role by prefixing the relation name by 'reverse_'. Also, relation values may be an entity or eid, a list of entities or eids. """ rql, qargs, pendingrels, attrcache = cls._cw_build_entity_query(kwargs) if rql: rql = "INSERT %s X: %s" % (cls.__regid__, rql) else: rql = "INSERT %s X" % (cls.__regid__) try: created = execute(rql, qargs).get_entity(0, 0) except IndexError: raise Exception( "could not create a %r with %r (%r)" % (cls.__regid__, rql, qargs) ) created._cw_update_attr_cache(attrcache) cls._cw_handle_pending_relations(created.eid, pendingrels, execute) return created def __init__(self, req, rset=None, row=None, col=0): AppObject.__init__(self, req, rset=rset, row=row, col=col) self._cw_related_cache = {} self._cw_adapters_cache = {} if rset is not None: self.eid = rset[row][col] else: self.eid = None self._cw_is_saved = True self.cw_attr_cache = {} def __repr__(self): return "<Entity %s %s %s at %s>" % ( self.e_schema, self.eid, list(self.cw_attr_cache), id(self), ) def __lt__(self, other): return NotImplemented def __eq__(self, other): if isinstance(self.eid, int): return self.eid == other.eid return self is other def __hash__(self): if isinstance(self.eid, int): return self.eid return super(Entity, self).__hash__() def _cw_update_attr_cache(self, attrcache): trdata = self._cw.transaction_data uncached_attrs = trdata.get( "%s.storage-special-process-attrs" % self.eid, set() ) uncached_attrs.update(trdata.get("%s.dont-cache-attrs" % self.eid, set())) for attr in uncached_attrs: attrcache.pop(attr, None) self.cw_attr_cache.pop(attr, None) self.cw_attr_cache.update(attrcache) def _cw_dont_cache_attribute(self, attr, repo_side=False): """Called when some attribute has been transformed by a *storage*, hence the original value should not be cached **by anyone**. For example we have a special "fs_importing" mode in BFSS where a file path is given as attribute value and stored as is in the data base. Later access to the attribute will provide the content of the file at the specified path. We do not want the "filepath" value to be cached. """ trdata = self._cw.transaction_data trdata.setdefault("%s.dont-cache-attrs" % self.eid, set()).add(attr) if repo_side: trdata.setdefault("%s.storage-special-process-attrs" % self.eid, set()).add( attr ) def __json_encode__(self): """custom json dumps hook to dump the entity's eid which is not part of dict structure itself """ dumpable = self.cw_attr_cache.copy() dumpable["eid"] = self.eid return dumpable def cw_adapt_to(self, interface): """return an adapter the entity to the given interface name. return None if it can not be adapted. """ cache = self._cw_adapters_cache try: return cache[interface] except KeyError: adapter = self._cw.vreg["adapters"].select_or_none( interface, self._cw, entity=self ) cache[interface] = adapter return adapter def has_eid(self): # XXX cw_has_eid """return True if the entity has an attributed eid (False meaning that the entity has to be created """ try: int(self.eid) return True except (ValueError, TypeError): return False def cw_is_saved(self): """during entity creation, there is some time during which the entity has an eid attributed though it's not saved (eg during 'before_add_entity' hooks). You can use this method to ensure the entity has an eid *and* is saved in its source. """ return self.has_eid() and self._cw_is_saved def cw_check_perm(self, action): self.e_schema.check_perm(self._cw, action, eid=self.eid) def cw_has_perm(self, action): return self.e_schema.has_perm(self._cw, action, eid=self.eid) def view( self, __vid, __registry="views", w=None, initargs=None, **kwargs ): # XXX cw_view """shortcut to apply a view on this entity""" if initargs is None: initargs = kwargs else: initargs.update(kwargs) view = self._cw.vreg[__registry].select( __vid, self._cw, rset=self.cw_rset, row=self.cw_row, col=self.cw_col, **initargs, ) return view.render(row=self.cw_row, col=self.cw_col, w=w, **kwargs) def absolute_url(self, *args, **kwargs): # XXX cw_url """return an absolute url to view this entity""" # use *args since we don't want first argument to be "anonymous" to # avoid potential clash with kwargs if args: assert len(args) == 1, "only 0 or 1 non-named-argument expected" method = args[0] else: method = None if method in (None, "view"): kwargs["_restpath"] = self.rest_path() else: kwargs["rql"] = "Any X WHERE X eid %s" % self.eid return self._cw.build_url(method, **kwargs) def rest_path(self): # XXX cw_rest_path """returns a REST-like (relative) path for this entity""" mainattr, needcheck = self.cw_rest_attr_info() etype = str(self.e_schema) path = etype.lower() fallback = False if mainattr != "eid": value = getattr(self, mainattr) if not can_use_rest_path(value): mainattr = "eid" path = None elif needcheck: # make sure url is not ambiguous try: nbresults = self.__unique except AttributeError: rql = "Any COUNT(X) WHERE X is %s, X %s %%(value)s" % ( etype, mainattr, ) nbresults = self.__unique = self._cw.execute(rql, {"value": value})[ 0 ][0] if nbresults != 1: # ambiguity? mainattr = "eid" path = None if mainattr == "eid": value = self.eid if path is None: # fallback url: <base-url>/<eid> url is used as cw entities uri, # prefer it to <base-url>/<etype>/eid/<eid> return str(value) return "%s/%s" % (path, self._cw.url_quote(value)) def cw_attr_metadata(self, attr, metadata): """return a metadata for an attribute (None if unspecified)""" value = getattr(self, "%s_%s" % (attr, metadata), None) if value is None and metadata == "encoding": value = self._cw.vreg.property_value("ui.encoding") return value def printable_value( self, attr, value=_marker, attrtype=None, format="text/html", displaytime=True ): # XXX cw_printable_value """return a displayable value (i.e. unicode string) which may contains html tags """ attr = str(attr) if value is _marker: value = getattr(self, attr) if isinstance(value, str): value = value.strip() if value is None or value == "": # don't use "not", 0 is an acceptable value return "" if attrtype is None: attrtype = self.e_schema.destination(attr) props = self.e_schema.rdef(attr) if attrtype == "String": # internalinalized *and* formatted string such as schema # description... if props.internationalizable: value = self._cw._(value) attrformat = self.cw_attr_metadata(attr, "format") if attrformat: return self._cw_mtc_transform( value, attrformat, format, self._cw.encoding ) elif attrtype == "Bytes": attrformat = self.cw_attr_metadata(attr, "format") if attrformat: encoding = self.cw_attr_metadata(attr, "encoding") return self._cw_mtc_transform( value.getvalue(), attrformat, format, encoding ) return "" value = self._cw.printable_value( attrtype, value, props, displaytime=displaytime ) if format == "text/html": value = xml_escape(value) return value def _cw_mtc_transform(self, data, format, target_format, encoding, _engine=ENGINE): trdata = TransformData(data, format, encoding, appobject=self) data = _engine.convert(trdata, target_format).decode() if target_format == "text/html": data = soup2xhtml(data, self._cw.encoding) return data # entity cloning ########################################################## def copy_relations(self, ceid): # XXX cw_copy_relations """copy relations of the object with the given eid on this object (this method is called on the newly created copy, and ceid designates the original entity). By default meta and composite relations are skipped. Overrides this if you want another behaviour """ assert self.has_eid() execute = self._cw.execute skip_copy_for = {"subject": set(), "object": set()} for rtype, role in self.cw_skip_copy_for: assert role in ("subject", "object"), role skip_copy_for[role].add(rtype) for rschema in self.e_schema.subject_relations(): if rschema.type in skip_copy_for["subject"]: continue if rschema.final or rschema.meta or rschema.rule: continue # skip already defined relations if getattr(self, rschema.type): continue # XXX takefirst=True to remove warning triggered by ambiguous relations rdef = self.e_schema.rdef(rschema, takefirst=True) # skip composite relation if rdef.composite: continue # skip relation with card in ?1 else we either change the copied # object (inlined relation) or inserting some inconsistency if rdef.cardinality[1] in "?1": continue rql = "SET X %s V WHERE X eid %%(x)s, Y eid %%(y)s, Y %s V" % ( rschema.type, rschema.type, ) execute(rql, {"x": self.eid, "y": ceid}) self.cw_clear_relation_cache(rschema.type, "subject") for rschema in self.e_schema.object_relations(): if rschema.meta or rschema.rule: continue # skip already defined relations if self.related(rschema.type, "object"): continue if rschema.type in skip_copy_for["object"]: continue # XXX takefirst=True to remove warning triggered by ambiguous relations rdef = self.e_schema.rdef(rschema, "object", takefirst=True) # skip composite relation if rdef.composite: continue # skip relation with card in ?1 else we either change the copied # object (inlined relation) or inserting some inconsistency if rdef.cardinality[0] in "?1": continue rql = "SET V %s X WHERE X eid %%(x)s, Y eid %%(y)s, V %s Y" % ( rschema.type, rschema.type, ) execute(rql, {"x": self.eid, "y": ceid}) self.cw_clear_relation_cache(rschema.type, "object") # data fetching methods ################################################### @cached def as_rset(self): # XXX .cw_as_rset """returns a resultset containing `self` information""" rset = ResultSet( [(self.eid,)], "Any X WHERE X eid %(x)s", {"x": self.eid}, [(self.cw_etype,)], ) rset.req = self._cw return rset def _cw_to_complete_relations(self): """by default complete final relations to when calling .complete()""" for rschema in self.e_schema.subject_relations(): if rschema.final: continue targets = rschema.objects(self.e_schema) if rschema.inlined: matching_groups = self._cw.user.matching_groups if all( matching_groups(e.get_groups("read")) and rschema.rdef(self.e_schema, e).get_groups("read") for e in targets ): yield rschema, "subject" def _cw_to_complete_attributes(self, skip_bytes=True, skip_pwd=True): for rschema, attrschema in self.e_schema.attribute_definitions(): # skip binary data by default if skip_bytes and attrschema.type == "Bytes": continue attr = rschema.type if attr == "eid": continue # password retrieval is blocked at the repository server level rdef = rschema.rdef(self.e_schema, attrschema) if not self._cw.user.matching_groups(rdef.get_groups("read")) or ( attrschema.type == "Password" and skip_pwd ): self.cw_attr_cache[attr] = None continue yield attr _cw_completed = False def complete( self, attributes=None, skip_bytes=True, skip_pwd=True ): # XXX cw_complete """complete this entity by adding missing attributes (i.e. query the repository to fill the entity) :type skip_bytes: bool :param skip_bytes: if true, attribute of type Bytes won't be considered """ assert self.has_eid() if self._cw_completed: return if attributes is None: self._cw_completed = True varmaker = rqlvar_maker() V = next(varmaker) rql = ["WHERE %s eid %%(x)s" % V] selected = [] for attr in attributes or self._cw_to_complete_attributes(skip_bytes, skip_pwd): # if attribute already in entity, nothing to do if attr in self.cw_attr_cache: continue # case where attribute must be completed, but is not yet in entity var = next(varmaker) rql.append("%s %s %s" % (V, attr, var)) selected.append((attr, var)) # +1 since this doesn't include the main variable lastattr = len(selected) + 1 if attributes is None: # fetch additional relations (restricted to 0..1 relations) for rschema, role in self._cw_to_complete_relations(): rtype = rschema.type if self.cw_relation_cached(rtype, role): continue # at this point we suppose that: # * this is a inlined relation # * entity (self) is the subject # * user has read perm on the relation and on the target entity assert rschema.inlined assert role == "subject" var = next(varmaker) # keep outer join anyway, we don't want .complete to crash on # missing mandatory relation (see #1058267) rql.append("%s %s %s?" % (V, rtype, var)) selected.append(((rtype, role), var)) if selected: # select V, we need it as the left most selected variable # if some outer join are included to fetch inlined relations rql = "Any %s,%s %s" % ( V, ",".join(var for attr, var in selected), ",".join(rql), ) try: rset = self._cw.execute(rql, {"x": self.eid}, build_descr=False)[0] except IndexError: raise Exception( "unable to fetch attributes for entity with eid %s" % self.eid ) # handle attributes for i in range(1, lastattr): self.cw_attr_cache[str(selected[i - 1][0])] = rset[i] # handle relations for i in range(lastattr, len(rset)): rtype, role = selected[i - 1][0] value = rset[i] if value is None: rrset = ResultSet([], rql, {"x": self.eid}) rrset.req = self._cw else: rrset = self._cw.eid_rset(value) self.cw_set_relation_cache(rtype, role, rrset) def cw_attr_value(self, name): """get value for the attribute relation <name>, query the repository to get the value if necessary. :type name: str :param name: name of the attribute to get """ try: return self.cw_attr_cache[name] except KeyError: if not self.cw_is_saved(): return None rql = "Any A WHERE X eid %%(x)s, X %s A" % name try: rset = self._cw.execute(rql, {"x": self.eid}) except Unauthorized: self.cw_attr_cache[name] = value = None else: assert rset.rowcount <= 1, (self, rql, rset.rowcount) try: self.cw_attr_cache[name] = value = rset.rows[0][0] except IndexError: # probably a multisource error self.critical( "can't get value for attribute %s of entity with eid %s", name, self.eid, ) if self.e_schema.destination(name) == "String": self.cw_attr_cache[name] = value = self._cw._("unaccessible") else: self.cw_attr_cache[name] = value = None return value def related( self, rtype, role="subject", limit=None, entities=False, # XXX .cw_related safe=False, targettypes=None, ): """returns a resultset of related entities :param rtype: the name of the relation, aka relation type :param role: the role played by 'self' in the relation ('subject' or 'object') :param limit: resultset's maximum size :param entities: if True, the entites are returned; if False, a result set is returned :param safe: if True, an empty rset/list of entities will be returned in case of :exc:`Unauthorized`, else (the default), the exception is propagated :param targettypes: a tuple of target entity types to restrict the query """ rtype = str(rtype) # Caching restricted/limited results is best avoided. cacheable = limit is None and targettypes is None if cacheable: cache_key = "%s_%s" % (rtype, role) if cache_key in self._cw_related_cache: return self._cw_related_cache[cache_key][entities] if not self.has_eid(): if entities: return [] return self._cw.empty_rset() rql = self.cw_related_rql(rtype, role, limit=limit, targettypes=targettypes) try: rset = self._cw.execute(rql, {"x": self.eid}) except Unauthorized: if not safe: raise rset = self._cw.empty_rset() if cacheable: self.cw_set_relation_cache(rtype, role, rset) if entities: return tuple(rset.entities()) else: return rset def cw_related_rql(self, rtype, role="subject", targettypes=None, limit=None): return self.cw_related_rqlst( rtype, role=role, targettypes=targettypes, limit=limit ).as_string() def cw_related_rqlst( self, rtype, role="subject", targettypes=None, limit=None, sort_terms=None ): """Return the select node of the RQL query of entities related through `rtype` with this entity as `role`, possibly filtered by `targettypes`. The RQL query can be given a `limit` and sort terms with `sort_terms` arguments being a sequence of ``(<relation type>, <sort ascending>)`` (e.g. ``[('name', True), ('modification_date', False)]`` would lead to a sorting by ``name``, ascending and then by ``modification_date``, descending. If `sort_terms` is not specified the default sorting is by ``modification_date``, descending. """ vreg = self._cw.vreg rschema = vreg.schema[rtype] select = Select() mainvar, evar = select.get_variable("X"), select.get_variable("E") select.add_selected(mainvar) if limit is not None: select.set_limit(limit) select.add_eid_restriction(evar, "x", "Substitute") if role == "subject": rel = make_relation(evar, rtype, (mainvar,), VariableRef) select.add_restriction(rel) if targettypes is None: targettypes = rschema.objects(self.e_schema) else: select.add_constant_restriction(mainvar, "is", targettypes, "etype") gcard = greater_card(rschema, (self.e_schema,), targettypes, 0) else: rel = make_relation(mainvar, rtype, (evar,), VariableRef) select.add_restriction(rel) if targettypes is None: targettypes = rschema.subjects(self.e_schema) else: select.add_constant_restriction(mainvar, "is", targettypes, "etype") gcard = greater_card(rschema, targettypes, (self.e_schema,), 1) etypecls = vreg["etypes"].etype_class(targettypes[0]) if len(targettypes) > 1: fetchattrs = vreg["etypes"].fetch_attrs(targettypes) self._fetch_ambiguous_rtypes( select, mainvar, fetchattrs, targettypes, vreg.schema ) else: fetchattrs = etypecls.fetch_attrs etypecls.fetch_rqlst(self._cw.user, select, mainvar, fetchattrs, settype=False) # optimisation: remove ORDERBY if cardinality is 1 or ? (though # greater_card return 1 for those both cases) if gcard == "1": select.remove_sort_terms() elif not select.orderby: # Build a mapping (rtype, node) for relations usable for sorting. sorting_relations = {} for r in select.where.get_nodes(RqlRelation): lhs, rhs = r.children if lhs.variable != mainvar: continue if r.operator() != "=": continue rhs_term = rhs.children[0] if not isinstance(rhs_term, VariableRef): continue sorting_relations[r.r_type] = r sort_terms = sort_terms or [("modification_date", False)] for term, order in sort_terms: # Add a relation for sorting only if it is not only retrieved # (e.g. modification_date) instead of adding another variable # for sorting. This should not be problematic. rel = sorting_relations.get(term) if rel is None: mdvar = select.make_variable() rel = make_relation(mainvar, term, (mdvar,), VariableRef) select.add_restriction(rel) var = rel.children[1].children[0].variable select.add_sort_var(var, asc=order) return select # generic vocabulary methods ############################################## def cw_linkable_rql( self, rtype, targettype, role, ordermethod=None, vocabconstraints=True, lt_infos={}, limit=None, ): """build a rql to fetch targettype entities either related or unrelated to this entity using (rtype, role) relation. Consider relation permissions so that returned entities may be actually linked by `rtype`. `lt_infos` are supplementary informations, usually coming from __linkto parameter, that can help further restricting the results in case current entity is not yet created. It is a dict describing entities the current entity will be linked to, which keys are (rtype, role) tuples and values are a list of eids. """ return self._cw_compute_linkable_rql( rtype, targettype, role, ordermethod=None, vocabconstraints=vocabconstraints, lt_infos=lt_infos, limit=limit, unrelated_only=False, ) def cw_unrelated_rql( self, rtype, targettype, role, ordermethod=None, vocabconstraints=True, lt_infos={}, limit=None, ): """build a rql to fetch `targettype` entities unrelated to this entity using (rtype, role) relation. Consider relation permissions so that returned entities may be actually linked by `rtype`. `lt_infos` are supplementary informations, usually coming from __linkto parameter, that can help further restricting the results in case current entity is not yet created. It is a dict describing entities the current entity will be linked to, which keys are (rtype, role) tuples and values are a list of eids. """ return self._cw_compute_linkable_rql( rtype, targettype, role, ordermethod=None, vocabconstraints=vocabconstraints, lt_infos=lt_infos, limit=limit, unrelated_only=True, ) def _cw_compute_linkable_rql( self, rtype, targettype, role, ordermethod=None, vocabconstraints=True, lt_infos={}, limit=None, unrelated_only=False, ): """build a rql to fetch `targettype` entities that may be related to this entity using the (rtype, role) relation. By default (unrelated_only=False), this includes the already linked entities as well as the unrelated ones. If `unrelated_only` is True, the rql filters out the already related entities. """ ordermethod = ordermethod or "fetch_unrelated_order" rschema = self._cw.vreg.schema.rschema(rtype) rdef = rschema.role_rdef(self.e_schema, targettype, role) rewriter = RQLRewriter(self._cw) select = Select() # initialize some variables according to the `role` of `self` in the # relation (variable names must respect constraints conventions): # * variable for myself (`evar`) # * variable for searched entities (`searchvedvar`) if role == "subject": evar = subjvar = select.get_variable("S") searchedvar = objvar = select.get_variable("O") else: searchedvar = subjvar = select.get_variable("S") evar = objvar = select.get_variable("O") select.add_selected(searchedvar) if limit is not None: select.set_limit(limit) # initialize some variables according to `self` existence if rdef.role_cardinality(neg_role(role)) in "?1": # if cardinality in '1?', we want a target entity which isn't # already linked using this relation variable = select.make_variable() if role == "subject": rel = make_relation(variable, rtype, (searchedvar,), VariableRef) else: rel = make_relation(searchedvar, rtype, (variable,), VariableRef) select.add_restriction(Not(rel)) elif self.has_eid() and unrelated_only: # elif we have an eid, we don't want a target entity which is # already linked to ourself through this relation rel = make_relation(subjvar, rtype, (objvar,), VariableRef) select.add_restriction(Not(rel)) if self.has_eid(): rel = make_relation(evar, "eid", ("x", "Substitute"), Constant) select.add_restriction(rel) args = {"x": self.eid} if role == "subject": sec_check_args = {"fromeid": self.eid} else: sec_check_args = {"toeid": self.eid} existant = None # instead of 'SO', improve perfs else: args = {} sec_check_args = {} existant = searchedvar.name # undefine unused evar, or the type resolver will consider it select.undefine_variable(evar) # retrieve entity class for targettype to compute base rql etypecls = self._cw.vreg["etypes"].etype_class(targettype) etypecls.fetch_rqlst( self._cw.user, select, searchedvar, ordermethod=ordermethod ) # from now on, we need variable type resolving self._cw.vreg.compute_var_types(self._cw, select, args) # insert RQL expressions for schema constraints into the rql syntax tree if vocabconstraints: cstrcls = (RQLVocabularyConstraint, RQLConstraint) else: cstrcls = RQLConstraint lt_infos = pruned_lt_info(self.e_schema, lt_infos or {}) # if there are still lt_infos, use set to keep track of added eid # relations (adding twice the same eid relation is incorrect RQL) eidvars = set() for cstr in rdef.constraints: # consider constraint.mainvars to check if constraint apply if isinstance(cstr, cstrcls) and searchedvar.name in cstr.mainvars: if not self.has_eid(): if lt_infos: # we can perhaps further restrict with linkto infos using # a custom constraint built from cstr and lt_infos cstr = build_cstr_with_linkto_infos( cstr, args, searchedvar, evar, lt_infos, eidvars ) if cstr is None: continue # could not build constraint -> discard elif evar.name in cstr.mainvars: continue # compute a varmap suitable to RQLRewriter.rewrite argument varmap = dict( (v, v) for v in (searchedvar.name, evar.name) if v in select.defined_vars and v in cstr.mainvars ) # rewrite constraint by constraint since we want a AND between # expressions. rewriter.rewrite(select, [(varmap, (cstr,))], args, existant) # insert security RQL expressions granting the permission to 'add' the # relation into the rql syntax tree, if necessary rqlexprs = rdef.get_rqlexprs("add") if not self.has_eid(): rqlexprs = [ rqlexpr for rqlexpr in rqlexprs if searchedvar.name in rqlexpr.mainvars ] if rqlexprs and not rdef.has_perm(self._cw, "add", **sec_check_args): # compute a varmap suitable to RQLRewriter.rewrite argument varmap = dict( (v, v) for v in (searchedvar.name, evar.name) if v in select.defined_vars ) # rewrite all expressions at once since we want a OR between them. rewriter.rewrite(select, [(varmap, rqlexprs)], args, existant) # ensure we have an order defined if not select.orderby: select.add_sort_var(select.defined_vars[searchedvar.name]) # we're done, turn the rql syntax tree as a string rql = select.as_string() return rql, args def unrelated( self, rtype, targettype, role="subject", limit=None, ordermethod=None, lt_infos={}, ): # XXX .cw_unrelated """return a result set of target type objects that may be related by a given relation, with self as subject or object """ try: rql, args = self.cw_unrelated_rql( rtype, targettype, role, limit=limit, ordermethod=ordermethod, lt_infos=lt_infos, ) except Unauthorized: return self._cw.empty_rset() return self._cw.execute(rql, args) # relations cache handling ################################################# def cw_relation_cached(self, rtype, role): """return None if the given relation isn't already cached on the instance, else the content of the cache (a 2-uple (rset, entities)). """ return self._cw_related_cache.get("%s_%s" % (rtype, role)) def cw_set_relation_cache(self, rtype, role, rset): """set cached values for the given relation""" if rset: related = tuple(rset.entities(0)) rschema = self._cw.vreg.schema.rschema(rtype) if role == "subject": rcard = rschema.rdef(self.e_schema, related[0].e_schema).cardinality[1] target = "object" else: rcard = rschema.rdef(related[0].e_schema, self.e_schema).cardinality[0] target = "subject" if rcard in "?1": for rentity in related: rentity._cw_related_cache["%s_%s" % (rtype, target)] = ( self.as_rset(), (self,), ) else: related = () self._cw_related_cache["%s_%s" % (rtype, role)] = (rset, related) def cw_clear_relation_cache(self, rtype=None, role=None): """clear cached values for the given relation or the entire cache if no relation is given """ if rtype is None: self._cw_related_cache.clear() self._cw_adapters_cache.clear() else: assert role self._cw_related_cache.pop("%s_%s" % (rtype, role), None) def cw_clear_all_caches(self): """flush all caches on this entity. Further attributes/relations access will triggers new database queries to get back values. If you use custom caches on your entity class (take care to @cached!), you should override this method to clear them as well. """ # clear attributes cache self._cw_completed = False self.cw_attr_cache.clear() # clear relations cache self.cw_clear_relation_cache() # rest path unique cache try: del self.__unique except AttributeError: pass # raw edition utilities ################################################### def cw_set(self, **kwargs): """update this entity using given attributes / relation, working in the same fashion as :meth:`cw_instantiate`. Example (in a shell session): >>> c = rql('Any X WHERE X is Company').get_entity(0, 0) >>> p = rql('Any X WHERE X is Person').get_entity(0, 0) >>> c.cw_set(name=u'Logilab') >>> p.cw_set(firstname=u'John', lastname=u'Doe', works_for=c) You can also set relations where the entity has 'object' role by prefixing the relation name by 'reverse_'. Also, relation values may be an entity or eid, a list of entities or eids, or None (meaning that all relations of the given type from or to this object should be deleted). """ assert kwargs assert self.cw_is_saved(), ( "should not call set_attributes while entity " "hasn't been saved yet" ) rql, qargs, pendingrels, attrcache = self._cw_build_entity_query(kwargs) if rql: rql = "SET " + rql qargs["x"] = self.eid if " WHERE " in rql: rql += ", X eid %(x)s" else: rql += " WHERE X eid %(x)s" self._cw.execute(rql, qargs) # update current local object _after_ the rql query to avoid # interferences between the query execution itself and the cw_edited / # skip_security machinery self._cw_update_attr_cache(attrcache) self._cw_handle_pending_relations(self.eid, pendingrels, self._cw.execute) # XXX update relation cache def cw_delete(self, **kwargs): assert self.has_eid(), self.eid self._cw.execute( "DELETE %s X WHERE X eid %%(x)s" % self.e_schema, {"x": self.eid}, **kwargs ) # server side utilities #################################################### def _cw_clear_local_perm_cache(self, action): for rqlexpr in self.e_schema.get_rqlexprs(action): self._cw.local_perm_cache.pop((rqlexpr.eid, (("x", self.eid),)), None) # attribute and relation descriptors ########################################## class Attribute(object): """descriptor that controls schema attribute access""" def __init__(self, attrname): assert attrname != "eid" self._attrname = attrname def __get__(self, eobj, eclass): if eobj is None: return self return eobj.cw_attr_value(self._attrname) class Relation(object): """descriptor that controls schema relation access""" def __init__(self, rschema, role): self._rtype = rschema.type self._role = role def __get__(self, eobj, eclass): if eobj is None: raise AttributeError("%s can only be accessed from instances" % self._rtype) return eobj.related(self._rtype, self._role, entities=True) def __set__(self, eobj, value): raise NotImplementedError # entity adapters ############################################################# class Adapter(AppObject): """base class for adapters""" __registry__ = "adapters" class EntityAdapter(Adapter): """base class for entity adapters (eg adapt an entity to an interface) An example would be: >>> some_entity.cw_adapt_to('IDownloadable') """ def __init__(self, _cw, **kwargs): try: self.entity = kwargs.pop("entity") except KeyError: self.entity = kwargs["rset"].get_entity( kwargs.get("row") or 0, kwargs.get("col") or 0 ) Adapter.__init__(self, _cw, **kwargs) set_log_methods(Entity, getLogger("cubicweb.entity"))