Getting an item from DynamoDB table

Question

I am trying to get an attribute from a table in DynamoDB.  I can see all items in the table via a print and see the attributes in the list.  However, when I try to get just that attribute, I get a response of "none".

The example code was attained from: https://medium.com/@ramjoshi.blogs/aws-dynamodb-with-python-a-beginners-guide-b9cf101436b2

I am executing from Lambda.  Here's the code:
import json
import boto3
from boto3.dynamodb.conditions import Key

def lambda_handler(event, context):
    dynamodb = boto3.resource('dynamodb')
    table = dynamodb.Table('D1-Sites')  
    
    response = table.get_item(Key={'SitesID': '1'})
    print(response)
    
    item = response.get('D1-Website')
    
    print("Should be printing item")
    print(item)
    
    return {
        'statusCode': 200,
        'body': json.dumps('Hello from Lambda!')
    }

In the 1st print, I see a list of every attribute in record 1.
In the last one, it prints "None"

I would like to see the value for a specific attribute: D1-Website.

Any help is appreciated.

Paul · Answer

Hello,

response.get('D1-Website') tries to retrieve the value of the 'D1-Website' key directly from the response dictionary. However, since the response dictionary doesn't have a top-level key named 'D1-Website', this operation returns None. Instead, you should first extract the item from the response and then access the 'D1-Website' attribute from the item

response = table.get_item(Key={'SitesID': '1'})
item = response.get('Item', {})  # Provide a default value to handle None response
d1_website = item.get('D1-Website')

Petrus · Answer

Not out of the woods yet:  Here's the code now:

import json
import boto3
from boto3.dynamodb.conditions import Key

def lambda_handler(event, context):

dynamodb = boto3.resource('dynamodb')
    
    table = dynamodb.Table('D1-Sites')  
    
    response = table.get_item(Key={'SitesID': '1'})
    print ('response: ')
    print(response)
    
    # from re:Post
    item = response.get('D1-Website', {'SitesID': '1'}) # Provide a default value to handle
    d1_website = item.get('D1-Website')
    
    print('d1_website is:')
    print(d1_website)#print the URL
    
    return {
        'statusCode': 200,
        'body': json.dumps('Hello from Lambda!')
    }
And the response:
response: 
{'Item': {'D1-Pricing': 'https://pricingdayones.godaddysites.com/', 'D1-QnA': 'https://faqdayoneslive.godaddysites.com/', 'SitesID': '1', 'D1-Youtube': 'https://m.youtube.com/@DayOnes_live', 'D1-ArtistQuickGuide': 'artistguide.dayones.live', 'D1-FanQuickGuide': 'fanguide.dayones.live', 'D1-Website': 'http://dayones.live'},

d1_website is:
None

Printing the response from "table.get_item(Key={'SitesID': '1'})" shows indeed a list of the table variables for SitesID = 1....the Partition Key.  "D1-Website" is the last return from the attributes in the table with the value.

However, I am still getting a none in variable d1_website attempting ti get the data.  What have I not done correctly?

Peter

Antonio_Lagrotteria · Answer

As reported here: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GettingStarted.ReadItem.html
you may want to retrieve the item via `response["Item"]` first, and then by the field.

Getting an item from DynamoDB table

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