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如何通过忽略boto3中的空元素将JSON数据写入Dynamodb

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我想将以下数据组写入Dynamodb .
大约有100个数据 . 由于不一定需要图像，因此存在具有和不具有image_url元素的混合 .

（questionsList.json）

{
  "q_id" : "001",
  "q_body" : "Where is the capital of the United States?",
  "q_answer" : "Washington, D.C.",
  "image_url" : "/Washington.jpg",
  "keywords" : [
    "UnitedStates",
    "Washington"
  ]
},
{
  "q_id" : "002",
  "q_body" : "Where is the capital city of the UK?",
  "q_answer" : "London",
  "image_url" : "",
  "keywords" : [
    "UK",
    "London"
  ]
},

由于它是写入测试阶段，因此要使用无服务器框架的serverless-dynamodb-local插件而不是 生产环境 环境在localhost：8000中编写要写入的Dynamodb .
为了将上述JSON数据写入此Dynamodb，我在Boto 3（AWS SDK for Python）中编写了以下代码 .

from __future__ import print_function
import boto3
import codecs
import json

dynamodb = boto3.resource('dynamodb', region_name='us-east-1', endpoint_url="http://localhost:8000")

table = dynamodb.Table('questionListTable')

with open("questionList.json", "r", encoding='utf-8') as json_file:
items = json.load(json_file)
for item in items:
    q_id = item['q_id']
    q_body = item['q_body']
    q_answer = item['q_answer']
    image_url = item['image_url']
    keywords = item['keywords']

    print("Adding detail:", q_id, q_body)

    table.put_item(
        Item={
            'q_id': q_id,
            'q_body': q_body,
            'q_answer': q_answer,
            'image_url': image_url,
            'keywords': keywords,
        }
    )

执行此代码时，空字符部分中会发生以下错误 .

botocore.exceptions.ClientError：调用PutItem操作时发生错误（ValidationException）：一个或多个参数值无效：AttributeValue可能不包含空字符串

显然它似乎是由JSON的空字符引起的 .
如果从写入目标中排除包含空字符的image_url，如下所示，写入完成没有任何问题 .

from __future__ import print_function
import boto3
import codecs
import json

dynamodb = boto3.resource('dynamodb', region_name='us-east-1', endpoint_url="http://localhost:8000")

table = dynamodb.Table('questionListTable')

with open("questionList.json", "r", encoding='utf-8') as json_file:
items = json.load(json_file)
for item in items:
    q_id = item['q_id']
    q_body = item['q_body']
    q_answer = item['q_answer']
    #image_url = item['image_url']
    keywords = item['keywords']

    print("Adding detail:", q_id, q_body)

    table.put_item(
        Item={
            'q_id': q_id,
            'q_body': q_body,
            'q_answer': q_answer,
            #'image_url': image_url,
            'keywords': keywords,
        }
    )

由于DynamoDB是NoSQL，可能还有其他方法可以很好地利用这些特性，但是如何更正代码来编写忽略空字符的上述数据呢？我想说"if image_url exists, write it if it does not, ignore it."

谢谢 .

python json amazon-web-services amazon-dynamodb boto3

1 回答

  • 2

    我解决了我的问题 . 您可以按如下方式设置null .

    from __future__ import print_function
import boto3
import codecs
import json

dynamodb = boto3.resource('dynamodb', region_name='ap-northeast-1', endpoint_url="http://localhost:8000")

table = dynamodb.Table('questionListTable')

with open("questionList.json", "r", encoding='utf-8_sig') as json_file:
    items = json.load(json_file)
    for item in items:
    q_id = item['q_id']
    q_body = item['q_body']
    q_answer = item['q_answer']
    image_url = item['image_url'] if item['image_url'] else None
    keywords = item['keywords'] if item['keywords'] else None

    print("Adding detail:", q_id, q_body)

    table.put_item(
        Item={
            'q_id': q_id,
            'q_body': q_body,
            'q_answer': q_answer,
            'image_url': image_url,
            'keywords': keywords,
        }
    )

    要检查Dynamodb的情况，请使用无服务器框架的脱机插件在本地环境中运行API网关 . 当我使用Postman实际调用API时，Null已正确插入值中 .

    {
  "q_id" : "001",
  "q_body" : "Where is the capital of the United States?",
  "q_answer" : "Washington, D.C.",
  "image_url" : "/Washington.jpg",
  "keywords" : [
    "UnitedStates",
    "Washington"
  ]
},
{
  "q_id" : "002",
  "q_body" : "Where is the capital city of the UK?",
  "q_answer" : "London",
  "image_url" : "null",
  "keywords" : [
    "UK",
    "London"
  ]
},
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