Lambda error "TypeError: 'str' object does not support item assignment Traceback"

Question

我正在尝试

import json
import uuid
import boto3

def lambda_handler(event, context):
    
    dynamo_client = boto3.resource('dynamodb')
    loadeo_carrier_company = dynamo_client.Table('loadeo_carrier_company')
    
    
    item = {}
    item = event['body']
    print(item)
    item['company_id'] = str(uuid.uuid4())
    
    print (type(item))
    try:
        loadeo_carrier_company.put_item(
          
            Item=item
        )
        return {
            "statusCode": 200,
            "headers" : {
                "Access-Control-Allow-Origin" : "*"
            },
            "message": json.dumps("Record has been inserted"),
            "body": item
        }
    except Exception as e:
            return {
                "statusCode": 500,
                "headers" : {
                    "Access-Control-Allow-Origin" : "*"
                },
                "message": "Error: Unable to save record!"
            }

此代码。

当我通过 Lambda 测试事件对其进行测试时，它工作正常。但是当我创建一个 API 并用邮递员尝试时显示内部服务器错误但是当我查看云监视日志时显示以下错误。

    [ERROR] TypeError: 'str' object does not support item assignment
Traceback (most recent call last):
  File "/var/task/lambda_function.py", line 19, in lambda_handler
    item['company_id'] = str(uuid.uuid4())

注意： Lambda 测试活动运行良好。

"body": {
  "company_name" : "waveaxis pvt ltd",
  "mc_number" : "00000",
  "email_adderess": "waveaxis@waveaxis.co.in",
  "phone_number" : "+91 1234567890",
  "company_address" : "Kormangala, Bengaluru"

},

尝试答案后：

当我从 lambda 测试事件中测试它时：

   {
  "errorMessage": "the JSON object must be str, bytes or bytearray, not dict",
  "errorType": "TypeError",
  "stackTrace": [
    "  File \"/var/task/lambda_function.py\", line 17, in lambda_handler\n    item = json.loads(event['body'])\n",
    "  File \"/var/lang/lib/python3.8/json/__init__.py\", line 341, in loads\n    raise TypeError(f'the JSON object must be str, bytes or bytearray, '\n"
  ]
}

当我从邮递员那里打电话时。执行在 try 块之前停止，没有错误

编辑 2：为事件

打印 json

{
   "resource":"/",
   "path":"/",
   "httpMethod":"PUT",
   "headers":{
      "Accept":"*/*",
      "Accept-Encoding":"gzip, deflate, br",
      "Authorization":"Bearer eyJraWQiOiJCUUl6ZkxcL1VOdm9QTDVxNExlWGFRNXNxOG1mVmhmXC9rK3ZJUDdYc0p0VjQ9IiwiYWxnIjoiUlMyNTYifQ.eyJzdWIiOiJkYjdkODBmOC1mY2VhLTQwYjItYTZhYi1jMjhhNTZiMTI1NDIiLCJ0b2tlbl91c2UiOiJhY2Nlc3MiLCJzY29wZSI6ImNhcnJpZXJcL3JlYWQgY2FycmllclwvdXBkYXRlIGNhcnJpZXJcL2RlbGV0ZSIsImF1dGhfdGltZSI6MTYwMjA0NDQ5NywiaXNzIjoiaHR0cHM6XC9cL2NvZ25pdG8taWRwLnVzLWVhc3QtMS5hbWF6b25hd3MuY29tXC91cy1lYXN0LTFfWW5nVnJxYUFGIiwiZXhwIjoxNjAyMDQ4MDk3LCJpYXQiOjE2MDIwNDQ0OTcsInZlcnNpb24iOjIsImp0aSI6ImExMzg4ZGUyLTRhZWQtNGI2MC04YjM0LWYzN2I1N2RjM2ZmMiIsImNsaWVudF9pZCI6IjVlZzU1NWhpNzAwZ21lbWc3N3B0NWkzbDIyIiwidXNlcm5hbWUiOiJHb29nbGVfMTEyNjUyMTUzMDI4OTQyNjAzNDM5In0.XMy9GP03o5EYrcLtQFzrMV6KID4IlDI_n0WrHa8osY_7CeeDjaCjH6Dtr766TAommLUzcLoKt-NrBUdq0Zfx-BL919j25rwiZXJbHiZP_4y9n891ddOXfPabO7n8O84-63W6l13QEBozuc21vXi7vuE_dSJ7KAgute46KP3LyoS73WPDhYim_7HZJO8pVedk64hhGNZsYWv6VU5QeQyqPl926spA25ZBo_z5dcoBnMZ_i2n5nz6qxRcINOKfMXL1f4_nDRbtKb5Pd33hKnsKYLkxEI0mrT1JKPJhkJRg9vGqaKcd13oqrigJRFSXYuVQuKNDluc38KbQJcwUoXDjjA",
      "Content-Type":"application/json",
      "Host":"661ny3iw92.execute-api.us-east-2.amazonaws.com",
      "Postman-Token":"654cfdd0-8080-48a5-8758-3aa7e5bcefcc",
      "User-Agent":"PostmanRuntime/7.26.5",
      "X-Amzn-Trace-Id":"Root=1-5fa13860-63da2718701bf3fc458c78e1",
      "X-Forwarded-For":"157.49.141.105",
      "X-Forwarded-Port":"443",
      "X-Forwarded-Proto":"https"
   },
   "multiValueHeaders":{
      "Accept":[
         "*/*"
      ],
      "Accept-Encoding":[
         "gzip, deflate, br"
      ],
      "Authorization":[
         "Bearer eyJraWQiOiJCUUl6ZkxcL1VOdm9QTDVxNExlWGFRNXNxOG1mVmhmXC9rK3ZJUDdYc0p0VjQ9IiwiYWxnIjoiUlMyNTYifQ.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.XMy9GP03o5EYrcLtQFzrMV6KID4IlDI_n0WrHa8osY_7CeeDjaCjH6Dtr766TAommLUzcLoKt-NrBUdq0Zfx-BL919j25rwiZXJbHiZP_4y9n891ddOXfPabO7n8O84-63W6l13QEBozuc21vXi7vuE_dSJ7KAgute46KP3LyoS73WPDhYim_7HZJO8pVedk64hhGNZsYWv6VU5QeQyqPl926spA25ZBo_z5dcoBnMZ_i2n5nz6qxRcINOKfMXL1f4_nDRbtKb5Pd33hKnsKYLkxEI0mrT1JKPJhkJRg9vGqaKcd13oqrigJRFSXYuVQuKNDluc38KbQJcwUoXDjjA"
      ],
      "Content-Type":[
         "application/json"
      ],
      "Host":[
         "661ny3iw92.execute-api.us-east-2.amazonaws.com"
      ],
      "Postman-Token":[
         "654cfdd0-8080-48a5-8758-3aa7e5bcefcc"
      ],
      "User-Agent":[
         "PostmanRuntime/7.26.5"
      ],
      "X-Amzn-Trace-Id":[
         "Root=1-5fa13860-63da2718701bf3fc458c78e1"
      ],
      "X-Forwarded-For":[
         "157.49.141.105"
      ],
      "X-Forwarded-Port":[
         "443"
      ],
      "X-Forwarded-Proto":[
         "https"
      ]
   },
   "queryStringParameters":"None",
   "multiValueQueryStringParameters":"None",
   "pathParameters":"None",
   "stageVariables":"None",
   "requestContext":{
      "resourceId":"529nsbfu6a",
      "resourcePath":"/",
      "httpMethod":"PUT",
      "extendedRequestId":"VbW_FFkYCYcF3PQ=",
      "requestTime":"03/Nov/2020:11:00:48 +0000",
      "path":"/dev",
      "accountId":"272075499248",
      "protocol":"HTTP/1.1",
      "stage":"dev",
      "domainPrefix":"661ny3iw92",
      "requestTimeEpoch":1604401248435,
      "requestId":"970dd9d2-9b35-45c5-b194-806060e27d10",
      "identity":{
         "cognitoIdentityPoolId":"None",
         "accountId":"None",
         "cognitoIdentityId":"None",
         "caller":"None",
         "sourceIp":"157.49.141.105",
         "principalOrgId":"None",
         "accessKey":"None",
         "cognitoAuthenticationType":"None",
         "cognitoAuthenticationProvider":"None",
         "userArn":"None",
         "userAgent":"PostmanRuntime/7.26.5",
         "user":"None"
      },
      "domainName":"661ny3iw92.execute-api.us-east-2.amazonaws.com",
      "apiId":"661ny3iw92"
   },
   "body":"{\r\n    \"company_name\": \"waveaxis pvt ltd\",\r\n    \"mc_number\": \"00000\",\r\n    \"email_adderess\": \"waveaxis@waveaxis.co.in\",\r\n    \"phone_number\": \"+91 1234567890\",\r\n    \"company_address\": \"Kormangala, Bengaluru\"\r\n}\r\n",
   "isBase64Encoded":False
}

Answer 1

根据我的记忆，您的 event['body'] 可能只是一个 json 字符串，而不是实际的 json。

因此，而不是

item = event['body']

你可以使用

item = json.loads(event['body'])

应该将 json 字符串解析为 json 对象。

更新

根据 event 的发布形式，您应该使用 ast，而不是 json

import ast

item = ast.literal_eval(event['body'])

Lambda error "TypeError: 'str' object does not support item assignment Traceback"

Lambda error "TypeError: 'str' object does not support item assignment Traceback"

amazon-web-services

python-3.x

postman

aws-lambda

aws-api-gateway

更新