# HTTP Gateways (optional)

Table of Contents

As part of the Airnode deployment you can decide to deploy two different HTTP Gateways.

HTTP Gateway: testing
HTTP Signed Data Gateway: production use

# Gateway Differences

Both gateways are setup identically. The differences are in their purpose and response. Gateways are allowed only when deploying to AWS and GCP.

# HTTP Gateway

The regular HTTP gateway is strictly for testing purposes. Using a simple tool like CURL you can test that endpoints in the Airnode configuration are working properly without accessing the blockchain.

# HTTP Signed Data Gateway

The HTTP signed data gateway is used for production purposes. While it is executed in a similar way as the HTTP gateway, its response is signed and does not contain a rawValue field. This gateway is executed by an off-chain code source that may in turn push data to a blockchain.

# Setup

Enable either gateway in the config.json file fields nodeSettings.httpGateway and nodeSettings.httpSignedDataGateway.

enabled: A boolean to enable/disable for the gateway.
apiKey: A user defined API key to authenticate against the gateway. The key must have a length of between 30 - 120 characters.
maxConcurrency: (optional) A number higher than zero that represents the maximum number of serverless functions serving gateway requests. When omitted, there is no maximum concurrency set.

"nodeSettings": {
  "cloudProvider": {
    "type": "aws",
    "region": "us-east-1"
  },
  "airnodeWalletMnemonic": "${AIRNODE_WALLET_MNEMONIC}",
  "heartbeat": {...},
  "httpGateway": {
    "enabled": true,
    "apiKey": "${HTTP_GATEWAY_API_KEY}",
    "maxConcurrency": 20
  },
  "httpSignedDataGateway": {
    "enabled": true,
    "apiKey": "${HTTP_SIGNED_DATA_GATEWAY_API_KEY}",
    "maxConcurrency": 20
  },
  ...
},

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Add the desired endpoints the gateways can respond to in the triggers.http[n] and/or triggers.httpSignedData[n] arrays. The corresponding arrays do not need to match. You may want to test all endpoints but only serve certain endpoints using the HTTP signed data gateway or via RRP.

// in config.json
"triggers": {
  "rrp": [
    {
      "endpointId": "0x6db9e3e3d073ad12b66d28dd85bcf49f58577270b1cc2d48a43c7025f5c27af6",
      "oisTitle": "CoinGecko Basic Request",
      "endpointName": "coinMarketData",
    }
  ],
  "http": [
    {
      "endpointId": "0x6db9e3e3d073ad12b66d28dd85bcf49f58577270b1cc2d48a43c7025f5c27af6",
      "oisTitle": "CoinGecko Basic Request",
      "endpointName": "coinMarketData",
    }
  ],
  "httpSignedData": [
    {
      "endpointId": "0x6db9e3e3d073ad12b66d28dd85bcf49f58577270b1cc2d48a43c7025f5c27af6",
      "oisTitle": "CoinGecko Basic Request",
      "endpointName": "coinMarketData",
    }
  ]
}

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# Gateway URLs

A gateway URL is generated for each gateway (when enabled) when Airnode is deployed. You can obtain the URLs api.httpGatewayUrl and api.httpSignedDataGatewayUrl from the receipt.json file returned by the Airnode deployer. They are also available as part of the payload sent from Airnode's heartbeat to your specified heartbeat URL.

# Using CURL

In order to execute an endpoint served by either gateway, the following are required as part of the CURL call.

Make a POST request with the endpointId as a path parameter. An endpointId can found in config.json under triggers.http.endpointId or triggers.httpSignedData.endpointId.
Add the Content-Type header, set to application/json.
Add the x-api-key header, set to the apiKey. The x-api-key can found in config.json under nodeSettings.httpGateway.apiKey or nodeSettings.httpSignedDataGateway.apiKey.
Place the parameters/encodedParameters in the request body.

CURL Parameters	In	CURL Options
Content-Type	header	`-H 'Content-Type: application/json'`
x-api-key	header	`-H 'x-api-key: 8d890a46-799d-48b3-a337-8531e23dfe8e'`
endpointId	path	`<gatewayUrl>/0x6db9e3e3d0...c7025f5c27af6`
* parameters HTTP Gateway	body	`-d '{"parameters": {"param1": "myValue", "param2": 5}}'`
* encodedParameters HTTP Signed Data Gateway	body	`-d '{"encodedParameters": "0x3173737300....000"}'`

* Parameters for the gateways are named differently. The HTTP signed data gateway requires that the encodedParameters be encoded using Airnode ABI.

Replace <gatewayUrl> in the examples below with a URL from the receipt.json file using the httpGatewayUrl or httpSignedDataGatewayUrl field. The receipt.json file is created when you deploy an Airnode.

# Request

# Response

# Tutorials

The airnode-examples monorepo hosts examples demonstrating use of the HTTP Gateway and HTTP Signed Data Gateway, see here. Furthermore, there are additional examples of using CURL to call the HTTP gateway in both the Quick Deploy AWS and Quick Deploy GCP tutorials.

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