AWS AppSync: How to query the database inside resolver?

Question

I am use AWS AppSync and AWS Amplify
I have 2 models:

type Post {
   id: ID!
   title: String!
   description: String
   createdAt: String
}

type User {
   id: ID!
   username: String!
   age: Int!
}

I create a custom req.vtl file like that:

## [Start] Initialization default values. **
$util.qr($ctx.stash.put("defaultValues", $util.defaultIfNull($ctx.stash.defaultValues, {})))
#set( $createdAt = $util.time.nowISO8601() )

$util.qr($ctx.stash.defaultValues.put("id", $util.autoId()))

$util.qr($ctx.stash.defaultValues.put("createdAt", $createdAt ))
$util.qr($context.args.input.put("createdAt", $createdAt ))

$util.toJson({
  "version": "2018-05-29",
  "payload": {}
})
## [End] Initialization default values. **

Everything works perfectly fine but I would like to know how to query the database inside resolver?

Example 1: I want to check if the post.title already exist in other post.

$ctx.args.input.title

If yes, I will create a error:

$util.error("This post already exist")

Example 2: I want to check if the user is over 18 years old.

$ctx.args.input.userId

If no, I will create a error:

$util.error("Your are too young!")

What I want to know is how to communicate with the database (without use lambda function). Can you help me?

If you are other example, you are welcome.

Regards

AWS AppSync: How to query the database inside resolver?

0 Answers0