def register_model_query_hook(cls,
model,
name,
query_hook,
filter_hook,
result_filters=None):
"""Register a hook to be invoked when a query is executed.
Add the hooks to the _model_query_hooks dict. Models are the keys
of this dict, whereas the value is another dict mapping hook names to
callables performing the hook.
Each hook has a "query" component, used to build the query expression
and a "filter" component, which is used to build the filter expression.
Query hooks take as input the query being built and return a
transformed query expression.
Filter hooks take as input the filter expression being built and return
a transformed filter expression
"""
if callable(query_hook):
query_hook = utils.make_weak_ref(query_hook)
if callable(filter_hook):
filter_hook = utils.make_weak_ref(filter_hook)
if callable(result_filters):
result_filters = utils.make_weak_ref(result_filters)
cls._model_query_hooks.setdefault(model, {})[name] = {
'query': query_hook,
'filter': filter_hook,
'result_filters': result_filters
}
def register_hook(model, name, query_hook, filter_hook,
result_filters=None):
"""Register a hook to be invoked when a query is executed.
:param model: The DB Model that the hook applies to.
:type model: sqlalchemy orm model
:param name: A name for the hook.
:type name: str
:param query_hook: The method to be called to augment the query.
:type query_hook: callable or None
:param filter_hook: A method to be called to augment the query filter.
:type filter_hook: callable or None
:param result_filters: A Method to be called to filter the query result.
:type result_filters: callable or None
Adds the hook components to the _model_query_hooks dict. Models are the
keys of this dict, whereas the value is another dict mapping hook names
to callables performing the hook.
Each hook has three components:
"query", used to build the query expression
"filter", used to build the filter expression
"result_filters", used for final filtering on the query result
Query hooks take as input the query being built and return a
transformed query expression.
def mymodel_query_hook(context, original_model, query):
augmented_query = ...
return augmented_query
Filter hooks take as input the filter expression being built and return
a transformed filter expression
def mymodel_filter_hook(context, original_model, filters):
refined_filters = ...
return refined_filters
Result filter hooks take as input the query expression and the filter
expression, and return a final transformed query expression.
def mymodel_result_filter_hook(query, filters):
final_filters = ...
return query.filter(final_filters)
"""
if callable(query_hook):
query_hook = utils.make_weak_ref(query_hook)
if callable(filter_hook):
filter_hook = utils.make_weak_ref(filter_hook)
if callable(result_filters):
result_filters = utils.make_weak_ref(result_filters)
_model_query_hooks.setdefault(model, {})[name] = {
'query': query_hook,
'filter': filter_hook,
'result_filters': result_filters
}
def register_funcs(resource, funcs):
"""Add functions to extend a resource.
:param resource: A resource collection name.
:type resource: str
:param funcs: A list of functions.
:type funcs: list of callable
These functions take a resource dict and a resource object and
update the resource dict with extension data (possibly retrieved
from the resource db object).
def _extend_foo_with_bar(foo_res, foo_db):
foo_res['bar'] = foo_db.bar_info # example
return foo_res
"""
funcs = [utils.make_weak_ref(f) if callable(f) else f for f in funcs]
_resource_extend_functions.setdefault(resource, []).extend(funcs)
def register_dict_extend_funcs(cls, resource, funcs):
funcs = [utils.make_weak_ref(f) if callable(f) else f for f in funcs]
cls._dict_extend_functions.setdefault(resource, []).extend(funcs)
