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