transform-headers.md

description
This page provides the technical details of the Transform Headers policy

Transform Headers

Overview

You can use the transform-headers policy to override HTTP headers in incoming requests or outbound responses. You can override the HTTP headers by:

• Adding to or updating the list of headers
• Removing headers individually
• Defining a whitelist == Compatibility with APIM

Functional and implementation information for the transform-headers policy is organized into the following sections:

• Examples
• Configuration
• Compatibility Matrix
• Changelogs

Examples

{% hint style="warning" %} This policy can be applied to v2 APIs, v4 HTTP proxy APIs, and v4 message APIs. It cannot be applied to v4 TCP proxy APIs. {% endhint %}

{% hint style="info" %} The policy configuration for a v2 API using the legacy execution engine must include the scope. If the policy is applied to a v4 API or a v2 API using the emulated reactive engine, the configuration does not include scope. {% endhint %}

{% tabs %} {% tab title="v2 API example" %} Sample policy configuration:

"transform-headers": {
    "addHeaders": [
        {
            "name": "X-Gravitee-Request-Id",
            "value": "{#request.id}"
        }
    ],
    "removeHeaders": [
        "X-Gravitee-TransactionId"
    ],
    "whitelistHeaders": [
        "Content-Type",
        "Content-Length"
    ],
    "scope": "REQUEST"
}

Add a header from the request’s payload:

"transform-headers": {
    "addHeaders": [
        {
            "name": "X-Product-Id",
            "value": "{#jsonPath(#request.content, '$.product.id')}"
        }
    ]
    "scope": "REQUEST_CONTENT"
}

{% endtab %}

{% tab title="HTTP proxy API example" %} Sample policy configuration:

"transform-headers": {
    "addHeaders": [
        {
            "name": "X-Gravitee-Request-Id",
            "value": "{#request.id}"
        }
    ],
    "removeHeaders": [
        "X-Gravitee-TransactionId"
    ],
    "whitelistHeaders": [
        "Content-Type",
        "Content-Length"
    ],
}

Add a header from the request’s payload:

"transform-headers": {
    "addHeaders": [
        {
            "name": "X-Product-Id",
            "value": "{#jsonPath(#request.content, '$.product.id')}"
        }
    ]
}

{% endtab %}

{% tab title="Message API example" %} Sample policy configuration:

"transform-headers": {
    "addHeaders": [
        {
            "name": "X-Gravitee-Message-Id",
            "value": "{#message.id}"
        }
    ],
    "removeHeaders": [
        "X-Gravitee-TransactionId"
    ],
    "whitelistHeaders": [
        "Content-Type",
        "Content-Length"
    ],
}

Add a header from the message’s payload:

"transform-headers": {
    "addHeaders": [
        {
            "name": "X-Product-Id",
            "value": "{#jsonPath(#message.content, '$.product.id')}"
        }
    ]
}

{% endtab %} {% endtabs %}

Configuration

Phases

The phases checked below are supported by the transform-headers policy:

v2 Phases	Compatible?	v4 Phases	Compatible?
onRequest	true	onRequest	true
onResponse	true	onResponse	true
onRequestContent	true	onMessageRequest	true
onResponseContent	true	onMessageResponse	true

Compatibility matrix

The following is the compatibility matrix for APIM and the transform-headers policy:

Plugin Version	Supported APIM versions
1.x	3.x
3.x	4.0+

Changelogs

{% @github-files/github-code-block url="https://github.com/gravitee-io/gravitee-policy-transform-headers/blob/master/CHANGELOG.md" %}