umSqxvL8

1import boto3
2import json
3import os
4
5
6db = boto3.resource('dynamodb')
7connections_table = db.Table('hey-multiplayer-services')
8
9
10def lambda_handler(event, context):
11    connection_id = get_connection_id(event)
12    delete_db_item(connection_id)
13    notify_other_connections(connection_id, event)
14    return {
15        'statusCode': 200,
16        'body': json.dumps('Hello from Lambda!')
17    }
18    
19
20def notify_other_connections(this_connection_id, event):
21    items = connections_table.scan(ProjectionExpression="connectionId")
22    for item in items["Items"]:
23        print(item)
24        connection_id = item["connectionId"]
25        if connection_id == this_connection_id:
26            continue
27        send_message(this_connection_id, connection_id, event)
28
29
30def send_message(sender_connection_id, reciever_connection_id, event):
31    print("notify {} of {}".format(reciever_connection_id, sender_connection_id))
32    api = boto3.client(
33        'apigatewaymanagementapi', 
34        endpoint_url="https://" + event["requestContext"]["domainName"] + "/" + event["requestContext"]["stage"]
35    )
36    api.post_to_connection(
37        Data = json.dumps({
38            "action": "exit",
39            "connectionId": sender_connection_id
40        }),
41        ConnectionId = reciever_connection_id
42    )
43
44
45def get_connection_id(event):
46    return event['requestContext']['connectionId']
47
48
49def delete_db_item(connection_id):
50    connections_table.delete_item(
51        Key = {
52            'connectionId': connection_id
53        }
54    )
55