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python - 如何从 Python 中复杂的嵌套 JSON 响应中获取节点

问题描述

您好我有一个嵌套的 JSON 响应，需要获取特定的节点（显然，一个嵌套结构）。在下面给出的示例中，假设它是“body”，如果它不包含任何内部节点，则返回相同的元素，即。'body' ，如果 'body' 中有 'Message' 节点，那么它应该返回 'Message' 节点。如何在 Python 中处理这种情况。

{
  "messageId": "56ba2b85-fb61-4a28-97d3-941237228582",
  "receiptHandle": "AQEB9mKPGdkuDgQkH3tNZ5pMd",
  "body": {
    "Type": "Notification",
    "MessageId": "467a4ce6-4a1e-5cab-8801-1be6b30a621f",
    "TopicArn": "arn:aws:sns:us-east-2:ttttt:TEST",
    "Subject": "01  Publish for TEST ",
    "Message": "{\\\"Store\\\":\\\"I01\\\",\\\"Loc\\\":\\\"I03\\\",\\\"User\\\":\\\"P37\\\",\\\"Mile\\\":\\\"1500\\\",\\\"Status\\\":true}\"",
    "Timestamp": "2020-04-03T08:41:56.047Z",
    "SignatureVersion": "1",
    "Signature": "Kg",
    "SigningCertURL": "something.com",
    "UnsubscribeURL": "subscribermoke.com"
  },
  "attributes": {
    "ApproximateReceiveCount": "42",
    "SentTimestamp": "1585903316106",
    "SenderId": "AIDAJQR6QDGQ7PATMSYEY",
    "ApproximateFirstReceiveTimestamp": "1585903316106"
  },
  "messageAttributes": {},
  "eventSource": "aws:sqs",
  "eventSourceARN": "arn:aws:sqs:us-east-:jjjjjj:sample-Dev",
  "awsRegion": "us-east"
}

附加信息： 这是 JSON 正文中的一个小改动，请查找以供参考。

"消息" : "{\"Store\":\"I01\",\"Loc\":\"I03\",\"User\":\"P37\",\"Mile\":\" 1500\",\"Status\":true}"
我希望将“消息”中的内容作为字典

标签： pythonjsonaws-lambdaamazon-sqsamazon-sns

解决方案

你需要某种形式的递归......但首先你需要修复你的数据对象（我认为）。

这是您需要的大纲：

from pprint import pprint
import json

MESSAGE = {
  "messageId": "56ba2b85-fb61-4a28-97d3-941237228582",
  "receiptHandle": "AQEB9mKPGdkuDgQkH3tNZ5pMd",
  "body": {
    "Type": "Notification",
    "MessageId": "467a4ce6-4a1e-5cab-8801-1be6b30a621f",
    "TopicArn": "arn:aws:sns:us-east-2:ttttt:TEST",
    "Subject": "01  Publish for TEST ",
    "Message": "{\\\"Store\\\":\\\"I01\\\",\\\"Loc\\\":\\\"I03\\\",\\\"User\\\":\\\"P37\\\",\\\"Mile\\\":\\\"1500\\\",\\\"Status\\\":true}\"",
    "Timestamp": "2020-04-03T08:41:56.047Z",
    "SignatureVersion": "1",
    "Signature": "Kg",
    "SigningCertURL": "something.com",
    "UnsubscribeURL": "subscribermoke.com"
  },
  "attributes": {
    "ApproximateReceiveCount": "42",
    "SentTimestamp": "1585903316106",
    "SenderId": "AIDAJQR6QDGQ7PATMSYEY",
    "ApproximateFirstReceiveTimestamp": "1585903316106"
  },
  "messageAttributes": {},
  "eventSource": "aws:sqs",
  "eventSourceARN": "arn:aws:sqs:us-east-:jjjjjj:sample-Dev",
  "awsRegion": "us-east"
}

def find_messages_in_body(body):
    if "Message" in body:
        submsg = body["Message"]
        print(submsg)
        print(type(submsg))
        submsg = json.loads(submsg)
        submsg = find_messages_in_body(submsg)
        return(submsg)
    else:
        return body

pprint(find_messages_in_body(MESSAGE["body"]))

但是当你运行它时，你会发现它是炸弹，因为它的值submsg是一个字符串，而不是一个有效的 JSON 字符串。

那么......你想要的输出又是什么？您确定您正确复制粘贴了输入数据吗？您还有其他输入数据示例吗？

另外......是否有可能会有多个可能的“子消息”？如果是这样，您需要让它返回一个列表，或将其转换为生成器（使用yield而不是return语句）。但首先...检查您的数据对象：MESSAGE["body"]["Message"]此时不是有效的 JSON。

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