AWS AppSync JavaScript resolver function reference for HTTP

The AWS AppSync HTTP resolver functions enable you to send requests from AWS AppSync to any HTTP endpoint, and responses from your HTTP endpoint back to AWS AppSync. With your request handler, you can provide hints to AWS AppSync about the nature of the operation to be invoked. This section describes the different configurations for the supported HTTP resolver.

Request

type HTTPRequest = {
  method: 'PUT' | 'POST' | 'GET' | 'DELETE' | 'PATCH';
  params?: {
    query?: { [key: string]: any };
    headers?: { [key: string]: string };
    body?: any;
  };
  resourcePath: string;
};

The following snippet is an example of an HTTP POST request, with a text/plain body:

export function request(ctx) {
  return {
    method: 'POST',
    params: {
      headers: { 'Content-Type': 'text/plain' },
      body: 'this is an example of text body',
    },
    resourcePath: '/',
  };
}

Method

Note

This applies only to the Request handler.

HTTP method or verb (GET, POST, PUT, PATCH, or DELETE) that AWS AppSync sends to the HTTP endpoint.

"method": "PUT"

ResourcePath

Note

This applies only to the Request handler.

The resource path that you want to access. Along with the endpoint in the HTTP data source, the resource path forms the URL that the AWS AppSync service makes a request to.

"resourcePath": "/v1/users"

When the request is evaluated, this path is sent as part of the HTTP request, including the HTTP endpoint. For example, the previous example might translate to the following:

PUT <endpoint>/v1/users

Params fields

Note

This applies only to the Request handler.

Used to specify what action your search performs, most commonly by setting the query value inside the body. However, there are several other capabilities that can be configured, such as the formatting of responses.

headers

The header information, as key-value pairs. Both the key and the value must be strings.

For example:

"headers" : {
    "Content-Type" : "application/json"
}

Currently supported Content-Type headers are:

text/*
application/xml
application/json
application/soap+xml
application/x-amz-json-1.0
application/x-amz-json-1.1
application/vnd.api+json
application/x-ndjson

You can’t set the following HTTP headers:

HOST
CONNECTION
USER-AGENT
EXPECTATION
TRANSFER_ENCODING
CONTENT_LENGTH

query

Key-value pairs that specify common options, such as code formatting for JSON responses. Both the key and the value must be a string. The following example shows how you can send a query string as ?type=json:

"query" : {
    "type" : "json"
}

body

The body contains the HTTP request body that you choose to set. The request body is always a UTF-8 encoded string unless the content type specifies the charset.

"body":"body string"

Response

See an example here.