django-orchestra-test/orchestra/contrib/orders/helpers.py

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from django.core.exceptions import ObjectDoesNotExist
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from orchestra.core import services
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def get_related_object(origin, max_depth=2):
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"""
Introspects origin object and return the first related service object
WARNING this is NOT an exhaustive search but a compromise between cost and
flexibility. A more comprehensive approach may be considered if
a use-case calls for it.
"""
def related_iterator(node):
for field in node._meta.private_fields:
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if hasattr(field, 'ct_field'):
yield getattr(node, field.name)
for field in node._meta.fields:
if field.rel:
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try:
yield getattr(node, field.name)
except ObjectDoesNotExist:
pass
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# BFS model relation transversal
queue = [[origin]]
while queue:
models = queue.pop(0)
if len(models) > max_depth:
return None
node = models[-1]
if len(models) > 1:
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if type(node) in services:
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return node
for related in related_iterator(node):
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if related and related not in models:
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new_models = list(models)
new_models.append(related)
queue.append(new_models)