python - 如何淡化来自 dynamodb 流的 json
问题描述
event = event = {'Records': [{'eventID': '2339bc590c21035b84f8cc602b12c1d2', 'eventName': 'INSERT', 'eventVersion': '1.1', 'eventSource': 'aws:dynamodb', 'awsRegion': 'us-east-1', 'dynamodb': {'ApproximateCreationDateTime': 1595908037.0, 'Keys': {'id': {'S': '9'}}, 'NewImage': {'last_name': {'S': 'Hus'}, 'id': {'S': '9'}, 'age': {'S': '95'}}, 'SequenceNumber': '3100000000035684810908', 'SizeBytes': 23, 'StreamViewType': 'NEW_IMAGE'}, 'eventSourceARN': 'arn:aws:dynamodb:us-east-1:656441365658:table/glossary/stream/2020-07-28T00:26:55.462'}, {'eventID': 'bbd4073256ef3182b3c00f13ead09501', 'eventName': 'MODIFY', 'eventVersion': '1.1', 'eventSource': 'aws:dynamodb', 'awsRegion': 'us-east-1', 'dynamodb': {'ApproximateCreationDateTime': 1595908037.0, 'Keys': {'id': {'S': '2'}}, 'NewImage': {'last_name': {'S': 'JJ'}, 'id': {'S': '2'}, 'age': {'S': '5'}}, 'SequenceNumber': '3200000000035684810954', 'SizeBytes': 21, 'StreamViewType': 'NEW_IMAGE'}, 'eventSourceARN': 'arn:aws:dynamodb:us-east-1:656441365658:table/glossary/stream/2020-07-28T00:26:55.462'}, {'eventID': 'a9c90c0c4a5a4b64d0314c4557e94e28', 'eventName': 'INSERT', 'eventVersion': '1.1', 'eventSource': 'aws:dynamodb', 'awsRegion': 'us-east-1', 'dynamodb': {'ApproximateCreationDateTime': 1595908037.0, 'Keys': {'id': {'S': '10'}}, 'NewImage': {'last_name': {'S': 'Hus'}, 'id': {'S': '10'}, 'age': {'S': '95'}}, 'SequenceNumber': '3300000000035684810956', 'SizeBytes': 25, 'StreamViewType': 'NEW_IMAGE'}, 'eventSourceARN': 'arn:aws:dynamodb:us-east-1:656441365658:table/glossary/stream/2020-07-28T00:26:55.462'}, {'eventID': '288f4a424992e5917af0350b53f754dc', 'eventName': 'MODIFY', 'eventVersion': '1.1', 'eventSource': 'aws:dynamodb', 'awsRegion': 'us-east-1', 'dynamodb': {'ApproximateCreationDateTime': 1595908037.0, 'Keys': {'id': {'S': '1'}}, 'NewImage': {'last_name': {'S': 'V'}, 'id': {'S': '1'}, 'age': {'S': '2'}}, 'SequenceNumber': '3400000000035684810957', 'SizeBytes': 20, 'StreamViewType': 'NEW_IMAGE'}, 'eventSourceARN': 'arn:aws:dynamodb:us-east-1:656441365658:table/glossary/stream/2020-07-28T00:26:55.462'}]}
以上来自 dynamodb 流。我需要从上面提取一些值
代码低于没有返回
def deserialize(event):
data = {}
data["M"] = event
return extract_some(data)
def extract_some(event):
for key, value in list(event.items()):
if (key == "NULL"):
return None
if (key == "S" or key == "BOOL"):
return value
for record in event['Records']:
doc = deserialise(record['dynamodb']['NewImage'])
print (doc)
预计出局
{'last_name': 'Hus', 'id': '9', 'age': '95'}
{'last_name': 'JJ', 'id': '2', 'age': '5'}
{'last_name': 'Hus', 'id': '10', 'age': '95'}
{'last_name': 'V', 'id': '1', 'age': '2'}
解决方案
尝试这个,
from pprint import pprint
result = []
for r in event['Records']:
tmp = {}
for k, v in r['dynamodb']['NewImage'].items():
if "S" in v.keys() or "BOOL" in v.keys():
tmp[k] = v.get('S', v.get('BOOL', False))
elif 'NULL' in v:
tmp[k] = None
result.append(tmp)
pprint(result)
[{'age': '95', 'id': '9', 'last_name': 'Hus'},
{'age': '5', 'id': '2', 'last_name': 'JJ'},
{'age': '95', 'id': '10', 'last_name': 'Hus'},
{'age': '2', 'id': '1', 'last_name': 'V'}]
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