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#2527 - DynamoDB - Allow nested attributes in ProjectionExpressions

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This commit is contained in:
Bert Blommers 2019-11-03 14:02:25 +00:00
commit 6a601d7d5c
3 changed files with 305 additions and 38 deletions
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42
moto/dynamodb2/models.py
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@ -107,6 +107,19 @@ class DynamoType(object):
else:
self.value.pop(key)
def filter(self, projection_expressions):
nested_projections = [expr[0:expr.index('.')] for expr in projection_expressions if '.' in expr]
if self.is_map():
expressions_to_delete = []
for attr in self.value:
if attr not in projection_expressions and attr not in nested_projections:
expressions_to_delete.append(attr)
elif attr in nested_projections:
relevant_expressions = [expr[len(attr + '.'):] for expr in projection_expressions if expr.startswith(attr + '.')]
self.value[attr].filter(relevant_expressions)
for expr in expressions_to_delete:
self.value.pop(expr)
def __hash__(self):
return hash((self.type, self.value))
@ -477,6 +490,18 @@ class Item(BaseModel):
"%s action not support for update_with_attribute_updates" % action
)
# Filter using projection_expression
# Ensure a deep copy is used to filter, otherwise actual data will be removed
def filter(self, projection_expression):
expressions = [x.strip() for x in projection_expression.split(',')]
top_level_expressions = [expr[0:expr.index('.')] for expr in expressions if '.' in expr]
for attr in list(self.attrs):
if attr not in expressions and attr not in top_level_expressions:
self.attrs.pop(attr)
if attr in top_level_expressions:
relevant_expressions = [expr[len(attr + '.'):] for expr in expressions if expr.startswith(attr + '.')]
self.attrs[attr].filter(relevant_expressions)
class StreamRecord(BaseModel):
def __init__(self, table, stream_type, event_name, old, new, seq):
@ -774,11 +799,8 @@ class Table(BaseModel):
result = self.items[hash_key]
if projection_expression and result:
expressions = [x.strip() for x in projection_expression.split(",")]
result = copy.deepcopy(result)
for attr in list(result.attrs):
if attr not in expressions:
result.attrs.pop(attr)
result.filter(projection_expression)
if not result:
raise KeyError
@ -911,13 +933,10 @@ class Table(BaseModel):
if filter_expression is not None:
results = [item for item in results if filter_expression.expr(item)]
results = copy.deepcopy(results)
if projection_expression:
expressions = [x.strip() for x in projection_expression.split(",")]
results = copy.deepcopy(results)
for result in results:
for attr in list(result.attrs):
if attr not in expressions:
result.attrs.pop(attr)
result.filter(projection_expression)
results, last_evaluated_key = self._trim_results(
results, limit, exclusive_start_key
@ -1004,12 +1023,9 @@ class Table(BaseModel):
results.append(item)
if projection_expression:
expressions = [x.strip() for x in projection_expression.split(",")]
results = copy.deepcopy(results)
for result in results:
for attr in list(result.attrs):
if attr not in expressions:
result.attrs.pop(attr)
result.filter(projection_expression)
results, last_evaluated_key = self._trim_results(
results, limit, exclusive_start_key, index_name