我需要向我的 Javascript 添加什么才能显示来自我的 DynamoDB 表和 API 网关的命中计数器？

Question

I want to be able to retrieve the hit counter from my DynamoDB table. I have an API Gateway, Lambda, and DynamoDB table all working with each other correctly. So far the code I have hits the API, triggering a count in the dynamo table, however the count on my site stays at 0. I'm very new to Javascript so I was hoping I could get some guidance for this. Here's the code I have so far:

const countEl = document.getElementById('count');

updateVisitCount();

function updateVisitCount() {
    fetch('https://xxxxxxxxxx.execute-api.us-west-2.amazonaws.com/prod/')
    .then(res => res.json())
    .then(res => {
        countEl.innerHTML = res.value;
    })
}

My Lambda Function:

import json
import os

import boto3

ddb = boto3.resource('dynamodb')
table = ddb.Table(os.environ['HITS_TABLE_NAME'])
_lambda = boto3.client('lambda')


def handler(event, context):
    print('request: {}'.format(json.dumps(event)))
    table.update_item(
        Key={'path': event['path']},
        UpdateExpression='ADD hits :incr',
        ExpressionAttributeValues={':incr': 1}
    )

    resp = _lambda.invoke(
        FunctionName=os.environ['DOWNSTREAM_FUNCTION_NAME'],
        Payload=json.dumps(event),
    )

    body = resp['Payload'].read()

    print('downstream response: {}'.format(body))
    return json.loads(body)

Thanks for your help!

Answer 1

how often is the data on dynamodb updated?

the easy workaround is calling updateVisitCount() every N seconds.

You can try with this code. It will update value every 5 seconds

const countEl = document.getElementById('count');

function updateVisitCount() {
    fetch('https://xxxxxxxxxx.execute-api.us-west-2.amazonaws.com/prod/')
    .then(res => res.json())
    .then(res => {
        countEl.innerHTML = res.value;
    })
}

setInterval(updateVisitCount, 5000)