CODEWITHSUNDEEP
python-3.xaws-sdkboto3
NeuroWinter
NeuroWinter

Reputation: 511

Finding items between 2 dates using boto3 and dynamodb scan

I am in the process of moving my NodeJS backend over to Python3.6.

In NodeJS I was able to use the aws SDK to get items between two dates like so :

```

var now = moment().tz("Pacific/Auckland").format()
var yesterday = moment().add(-24,"Hours").tz("Pacific/Auckland").format()
var docClient = new AWS.DynamoDB.DocumentClient();
  var params = {
    TableName : process.env.TableName,
    FilterExpression : '#ts between :val1 and :val2',
    ExpressionAttributeNames: {
        "#ts": "timeStamp",
    },
    ExpressionAttributeValues: {
      ':val1': yesterday,
      ':val2': now
    }
  }

```

And this works fine, however the between function in boto3 does not seem to do the same thing.

This is the current code I am using to try get something similar:

```

import boto3
import time
from datetime import datetime, timedelta
from boto3.dynamodb.conditions import Key, Attr

dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table('table_name')

now = int(datetime.timestamp(datetime.now()))
three_hours_ago =  int(datetime.timestamp(datetime.now() - timedelta(hours=3)))

fe = Key('timeStamp').between(three_hours_ago,now);
response = table.scan(
                FilterExpression=fe
            )
print(response)

```

This returns no items, I am sure that there are items between these two dates.

Any help would be much appreciated.

Upvotes: 8

Views: 16845

Answers (2)

ispravnic
ispravnic

Reputation: 21

A possible solution could be:

attr = boto3.dynamodb.conditions.Attr('timeStamp')

response = table.scan(
                FilterExpression=attr.between(first_date,second_date)
            )

However, please note that the date should be formatted as YYYY-MM-DD (ISO 8601)

Upvotes: 2

NeuroWinter
NeuroWinter

Reputation: 511

I managed to resolve this using the following code:

now             = datetime.datetime.now()
three_hours_ago = now - datetime.timedelta(hours=3)
#  TODO make the db UTC 
now             = now.strftime('%FT%T+13:00')
three_hours_ago = three_hours_ago.strftime('%FT%T+13:00')

fe       = Key('timeStamp').between(three_hours_ago,now);
response = table.scan(
                FilterExpression=fe
            )

Upvotes: 16

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