EventBridge:Event transformation

Complete Event

The entire CloudEvents payload is delivered to the target as-is. No configuration is required.

Output:

{
    "id": "7adc8c1a-645d-4476-bdef-5d6fb57f****",
    "source": "acs.oss",
    "specversion": "1.0",
    "type": "oss:ObjectCreated:PostObject",
    "datacontenttype": "application/json",
    "dataschema": "http://example.com/test.json",
    "subject": "acs:oss:cn-hangzhou:1234567:xls-papk/game_apk/123.jpg",
    "time": "2020-08-17T16:04:46.149Asia/Shanghai",
    "aliyuneventbusname": "demo-bus",
    "aliyunregionid": "Shanghai",
    "data": {
        "name": "test",
        "scope": 100
    }
}

Partial Event

A single JSONPath expression extracts one value from the event.

Configuration:

$.data.name

Output:

test

Usage notes:

• Only one JSONPath expression is allowed per Partial Event configuration.

• The value can be up to 10,240 characters in length.

Constant

A fixed string replaces the event payload. The event itself acts purely as a trigger.

Configuration:

test1

Output:

test1

Usage notes:

• The value can be up to 10,240 characters in length.

Template

Template is the most flexible method. It works in two parts:

1. Variable -- A JSON object that maps variable names to JSONPath expressions (or fixed values). Each JSONPath expression extracts a value from the event.

2. Template -- A string or JSON structure that references the variables with ${variableName} syntax.

Configuration:

Variable:

{
    "name": "$.data.name",
    "constant": "Please deal with it timely."
}

Template:

The instance is broken, which name is ${name}, ${constant}

Output:

The instance is broken, which name is test, Please deal with it timely.

Usage notes:

• Variable values can be JSONPath expressions or fixed strings.

• Nested structures are not supported in variable definitions.

• The variable value can be up to 10,240 characters in length.

• The template value can be up to 10,240 characters in length.

Simple string

Variable:

{
    "name": "$.data.name",
    "state": "$.data.state"
}

Template:

"name ${name} is in ${state}"

Output:

"name test is in RUNNING"

Simple JSON

Variable:

{
    "name": "$.data.name",
    "state": "$.data.state"
}

Template:

{
    "name": "${name}",
    "state": "${state}"
}

Output:

{
    "name": "test",
    "state": "RUNNING"
}

JSON with variables and constants

Combine extracted values with hardcoded constants, arrays, and different data types in a single template.

Variable:

{
    "name": "$.data.name",
    "state": "$.data.state"
}

Template:

{
    "name": "${name}",
    "state": [
        9,
        "${state}",
        true
    ],
    "Transformed": "Yes"
}

Output:

{
    "name": "test",
    "state": [
        9,
        "RUNNING",
        true
    ],
    "Transformed": "Yes"
}

Nested JSON

To pass through nested objects or arrays from the event, reference the variable without quotes so that EventBridge injects the raw JSON structure.

The following example uses a different sample event:

{
    "id": "45ef4dewdwe1-7c35-447a-bd93-fab****",
    "source": "acs.imm",
    "specversion": "1.0",
    "subject": "acs.imm:cn-hangzhou:123456789098****:215672",
    "time": "2020-11-19T21:04:41+08:00",
    "type": "imm:FileMeta:Index",
    "aliyunaccountid": "123456789098****",
    "aliyunpublishtime": "2020-11-19T21:04:42.179PRC",
    "aliyuneventbusname": "default",
    "aliyunregionid": "cn-hangzhou",
    "aliyunpublishaddr": "172.25.XX.XX",
    "data": {
        "ProjectName": "test_project",
        "DatasetName": "test_dataset",
        "RequestId": "D2A3AE88-D17C-4CCC-B149-6651115C****",
        "StartTime": "2021-07-22T14:03:15.489885+08:00",
        "EndTime": "2021-07-22T14:05:15.489885+08:00",
        "Message": "InvalidParameter",
        "Success": false,
        "Files": [
            {
                "URI": "oss://bucket/file",
                "CustomId": "defaultId",
                "CustomLabels": {
                    "Key1": "Val1",
                    "Key2": "Val2"
                },
                "Error": "InternalError"
            }
        ]
    }
}

Variable:

{
    "ProjectName": "$.data.ProjectName",
    "Files": "$.data.Files"
}

Template (${Files} has no quotes because it references an array):

{
    "ProjectName": "${ProjectName}",
    "Files": ${Files}
}

Output:

{
    "ProjectName": "test_project",
    "Files": [
        {
            "URI": "oss://bucket/file",
            "CustomId": "defaultId",
            "CustomLabels": {
                "Key1": "Val1",
                "Key2": "Val2"
            },
            "Error": "InternalError"
        }
    ]
}

jsonEscape()

Escapes special characters in JSON strings to prevent embedded characters from breaking the JSON structure.

Variable:

{
    "var": "\"abc\""
}

Template:

{
    "text": "var is ${jsonEscape(var)}"
}

Output:

{
    "text": "var is \"abc\""
}

htmlEscape()

Escapes HTML special characters so they render as plain text. Use this function to prevent script injection when event data is embedded in HTML output.

Variable:

{
    "var": "<script>alert('unsafe');</script>"
}

Template:

<p>User Input: ${htmlEscape(var)}</p>

Output:

<p>User Input: &lt;script&gt;alert('unsafe');&lt;/script&gt;</p>