draft.py

from __future__ import print_function
from boto3.dynamodb.conditions import Key, Attr

import boto3
import json

def lambda_handler(event, context):

    instance = event['query']['instance']
    
    dynamo = boto3.resource('dynamodb').Table('draft')

    items = dynamo.scan(FilterExpression=Attr('instance').eq(instance))['Items']

    if event['query']['operation'] == "list":
        incomplete = [item for item in items if "content" not in item]
        complete = [item for item in items if "content" in item]
        
        if not incomplete:
            return {"state": "complete", "entries": { key: complete[key] for key in ["email", "content"] }}
        
        if incomplete:
            return {"state": "incomplete", "emails": [x['email'] for x in incomplete]}

    if event['query']['operation'] == "create":
        if items:
            return {"state": "error", "message": "An instance with that name already exists."}
        
        emails = event["params"]["emails"]
        
        if not emails:
            return {"state": "error", "message": "No email addresses provided."}

        
        if len(emails) > 20:
            return {"state": "error", "message": "Number of emails limited to 20."}

        
        for email in emails:
            # todo email tokens
            
            dynamo.put_item(
               Item={
                    'id': instance + "/" + email,
                    'instance': instance,
                    'updatetoken': 'testtoken'
                    }
            )
            
            return {"state": "success", "message": "Created draft."}

    if event['query']['operation'] == "complete":
        content = event["params"]["content"]
        email = event['query']['email']
        token = event['query']['token']
        
        if not content:
            return {"state": "error", "message": "No content provided."}
            
        dynamo.update_item(
            Key={ 'id': instance + "/" + email, 'instance': instance },
            UpdateExpression='SET content = :val1',
            ConditionExpression='updatetoken = :t',
            ExpressionAttributeValues={ ':val1': content, ':t': token }
        )
        
        return {"state": "success", "message": "Updated content for " + email + ": " + content}

    raise ValueError("Operation not found.")