The following code sample shows a trigger definition that defines a request structure that's different than the inbound webhook. The execute property processes the webhook and transforms the raw request into the desired schema (specified in the request property). .

"GCPPubSubNotificationTrigger": {
  "displayName": "Subscribe to a topic",
  "description": "This trigger detects when a message is publised to a subscribed topic.",
  "type": "webhook",
  "execute": "flow:mapNotificationFlow",
  "httpMethod": "POST",
  "request": "flow:DynamicInputFlowTrigger",
  "webhook": {
    "headers": [
      {
        "name": "from",
        "type": "string"
      },
      {
        "name": "content-type",
        "type": "string"
      },
      {
        "name": "host",
        "type": "string"
      },
      {
        "name": "content-length",
        "type": "string"
      },
      {
        "name": "user-agent",
        "type": "string"
      },
      {
        "name": "authorization",
        "type": "string"
      },
      {
        "name": "x-span-id",
        "type": "string"
      },
      {
        "name": "transfer-encoding",
        "type": "string"
      },
      {
        "name": "connection",
        "type": "string"
      },
      {
        "name": "accept-encoding",
        "type": "string"
      },
      {
        "name": "accept",
        "type": "string"
      }
    ],
    "body": {
      "schemaType": "application/schema+json",
      "schema": {
        "$ref": "#/schemas/NotificationSchemaGCP"
      }
    }
  },
  "subscription": {
    "register": "flow:CreateSubscriptionFlow",
    "deregister": "flow:DeleteSubscriptionFlow"
  },
  "configuration": [
    {
      "name": "TopicName",
      "displayName": "Select topic",
      "description": "",
      "type": "COMBO_BOX",
      "options": "flow:ListTopicsUIFlow",
      "required": true
    },
    {
      "name": "SchemaName",
      "displayName": "Schema type associated with topic",
      "description": "Schema type associated with topic",
      "type": "TEXT_BOX",
      "default": "flow:GetSchemaNameFlow",
      "required": true,
      "dependencies": {
        "TopicName": {
          "values": []
        }
      }
    },
    {
      "name": "SchemaSupport",
      "displayName": "Schema not supported",
      "description": "Schema not supported",
      "type": "TEXT_BOX",
      "default": "flow:SchemaNotSuportedFlow",
      "required": true,
      "dependencies": {
        "SchemaName": {
          "values": [
            "PROTOCOL_BUFFER",
            "AVRO"
          ]
        }
      }
    },
    {
      "name": "InputField",
      "displayName": "Provide JSON Sample",
      "description": "Provide JSON sample for data",
      "type": "TEXT_AREA",
      "required": true,
      "validation": "flow:ValidateJsonFlow",
      "dependencies": {
        "SchemaName": {
          "values": [
            "No schema"
          ]
        }
      }
    },
    {
      "name": "filter",
      "displayName": "Subscription filter",
      "description": "Max 256 characters. Example: attributes:k OR (attributes.k1=\"v\" AND NOT hasPrefix (attributes.k2,\"v\"))",
      "type": "TEXT_AREA",
      "required": false,
      "validation": "flow:ValidateFilterLengthFlow"
    },
    {
      "name": "ackDeadline",
      "displayName": "Acknowledgement deadline",
      "description": "Deadline time is from 10 seconds to 600 seconds.",
      "type": "TEXT_BOX",
      "required": true,
      "default": "10",
      "validation": "flow:ValidateAckDeadlineFlow"
    },
    {
      "name": "enableDeadLettering",
      "displayName": "Enable dead lettering",
      "description": "Subscriptions may configure a maximum number of delivery attempts. When a message cannot be delivered, it is republished to the specified dead-letter topic.",
      "default": "false",
      "type": "CHECK_BOX",
      "required": false
    },
    {
      "name": "deadLetterTopic",
      "displayName": "Select a dead-letter topic",
      "description": "Topic should have a subscription associated to it.",
      "type": "COMBO_BOX",
      "options": "flow:ListTopicsUIFlow",
      "required": true,
      "dependencies": {
        "enableDeadLettering": {
          "values": [
            "true"
          ]
        }
      }
    },
    {
      "name": "maxDeliveryAttempts",
      "displayName": "Maximun delivery attempts",
      "description": "Maximum delivery attempts is from 5 to 100.",
      "type": "TEXT_BOX",
      "required": true,
      "default": "5",
      "validation": "flow:ValidateMaxDeliveryAttemptsFlow",
      "dependencies": {
        "enableDeadLettering": {
          "values": [
            "true"
          ]
        }
      }
    },
    {
      "name": "enableMessageOrdering",
      "displayName": "Order messages with an ordering key",
      "description": "When enabled, messages tagged with the same ordering key will be received in the order that they are published. This option cannot be changed later.",
      "default": "false",
      "type": "CHECK_BOX",
      "required": false
    },
    {
      "name": "retainAckedMessages",
      "displayName": "Retain acknowledged messages",
      "description": "When enabled, acknowledged messages are retained for the message retention duration specified above. This increases message storage fees.",
      "default": "false",
      "type": "CHECK_BOX",
      "required": false
    },
    {
      "name": "messageRetentionDuration",
      "displayName": "Specify message retention duration",
      "description": "Duration is from 10 minutes to 7 days",
      "default": "false",
      "type": "CHECK_BOX",
      "required": false
    },
    {
      "name": "days",
      "displayName": "Days",
      "description": "",
      "type": "COMBO_BOX",
      "options": "flow:DaysFlow",
      "required": true,
      "dependencies": {
        "messageRetentionDuration": {
          "values": [
            "true"
          ]
        }
      }
    },
    {
      "name": "hours",
      "displayName": "Hours",
      "description": "",
      "type": "COMBO_BOX",
      "options": "flow:HoursFlow",
      "required": true,
      "dependencies": {
        "days": {
          "values": [
            "0",
            "1",
            "2",
            "3",
            "4",
            "5",
            "6"
          ]
        }
      }
    },
    {
      "name": "minutes",
      "displayName": "Minutes",
      "description": "",
      "type": "COMBO_BOX",
      "options": "flow:MinutesFlow",
      "required": true,
      "dependencies": {
        "days": {
          "values": [
            "0",
            "1",
            "2",
            "3",
            "4",
            "5",
            "6"
          ]
        }
      }
    }
  ]
}

The following sample code shows a typical scenario, where the data transformation does not need to call an external API. Instead, the flow logic uses jq expressions and out-of-box functions provided by the Rapid Adapter Builder, which can be called from jq to execute this transformation.

In this example, a part of the webhook inbound message sent by the external application is base64 encoded. The flow logic extracts this part of the message and transforms it into the form that is presented in the integration mapper.

"mapNotificationFlow": {
  "id": "mapNotificationFlow",
  "version": "0.1",
  "start": "startState",
  "specVersion": "0.8",
  "functions": [
    {
      "name": "mapNotification",
      "operation": ".input|(if .message.attributes != null then (.message.attributes | to_entries | map({key: .key, value: .value})) as $attributes | .message.attributes = $attributes else . end | .message.data |= (if . then @base64d | fromjson else empty end))",
      "type": "expression"
    }
  ],
  "states": [
    {
      "actions": [
        {
          "functionRef": "mapNotification",
          "actionDataFilter": {
            "toStateData": "${ .output }"
          }
        }
      ],
      "name": "startState",
      "type": "operation",
      "end": true
    }
  ]
}