HTTP Trigger: Configuration & Handler

The HTTP trigger fires when an external system makes an HTTP request to the trigger endpoint.

Use case examples:

• Integrating with existing web services or webhooks.
• Allowing an external system to initiate a workflow on demand.
• Creating a user-facing endpoint to run a specific piece of logic.

Configuration and handler

You create an HTTP trigger by calling the HTTPCapability.trigger() method. Its configuration requires a set of authorized public keys to validate incoming request signatures.

import { cre, type Runtime, type HTTPPayload, Runner } from "@chainlink/cre-sdk"

type Config = {
  authorizedEVMAddress: string
}

// Callback function that runs when an HTTP request is received
const onHttpTrigger = (runtime: Runtime<Config>, payload: HTTPPayload): string => {
  runtime.log(`HTTP trigger received: ${payload.input.length} bytes`)
  // Your logic here...
  return "Request processed"
}

const initWorkflow = (config: Config) => {
  const httpTrigger = new cre.capabilities.HTTPCapability()

  return [
    cre.handler(
      httpTrigger.trigger({
        authorizedKeys: [
          {
            type: "KEY_TYPE_ECDSA_EVM",
            publicKey: config.authorizedEVMAddress,
          },
        ],
      }),
      onHttpTrigger
    ),
  ]
}

export async function main() {
  const runner = await Runner.newRunner<Config>()
  await runner.run(initWorkflow)
}

main()

About authorized keys:

• publicKey: An EVM address (e.g., "0xb08E004bd2b5aFf1F5F950d141f449B1c05800eb") that is authorized to trigger the workflow
• type: Must be "KEY_TYPE_ECDSA_EVM" (currently the only supported authentication method)
• Multiple keys: You can include multiple authorized addresses in the array

When an HTTP request is made to trigger your workflow, CRE verifies that the request was signed by a private key corresponding to one of the authorized addresses.

Callback and payload

The HTTP trigger passes an HTTPPayload to your callback. This object contains the request body (input) and the signing key (key) from the incoming HTTP request.

For the full type definition and all available fields, see the HTTP Trigger SDK Reference.

type RequestData = {
  message: string
  value: number
}

const onHttpTrigger = (runtime: Runtime<Config>, payload: HTTPPayload): string => {
  // The payload.input is a Uint8Array.
  // You can decode it to a JSON object using the decodeJson helper.
  const requestData = decodeJson<RequestData>(payload.input)
  runtime.log(`Received HTTP request: ${JSON.stringify(requestData)}`)

  // Your logic here...
  // The value returned from your callback will be sent back as the HTTP response.
  return `Request processed: ${requestData.message}`
}