assign-content.md

description
This page provides the technical details of the Assign Content policy

Assign Content

Overview

You can use the assign-content policy to change or transform the content of the request body or response body.

This policy is compatible with the Freemarker template engine, which allows you to apply complex transformations, such as transforming from XML to JSON and vice versa.

By default, you can access multiple objects from the template context: request and response bodies, dictionaries, context attributes and more.

Functional and implementation information for the assign-content policy is organized into the following sections:

• Examples
• Configuration
• Compatibility Matrix
• Errors
• 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 %}

{% tabs %} {% tab title="HTTP proxy API example" %} You could use the Assign Content policy to inject a dictionary value and application into the request payload:

{
  "example": "${context.dictionaries['my-dictionary']['my-value']}",
  "application": "${context.attributes['application']}"
}

{% endtab %}

{% tab title="Message API example" %} You could use the Assign Content policy to inject a dictionary value and metadata into the message:

{
  "example": "${message.dictionaries['my-dictionary']['my-value']}",
  "metadata": "${message.attributes['metadata']}"
}

{% endtab %} {% endtabs %}

Configuration

Sample policy configuration:

{% code title="Sample Configuration" %}

"policy-assign-content": {
    "scope":"REQUEST",
    "body":"Put your content here"
}

{% endcode %}

Phases

The phases checked below are supported by the assign-content policy:

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

Options

You can configure the assign-content policy with the following options:

Property	Required	Description	Type	Default
scope	true	The execution scope of the policy	scope	REQUEST
body	true	The data to push as request or response body content	string	-

Compatibility matrix

The following is the compatibility matrix for APIM and the assign-content policy:

Plugin Version	Supported APIM versions
Up to 1.6.x	Up to 3.9.x
1.7.x	3.10.x to 3.20.x
2.x	4.0+

Errors

Phase	HTTP status code	Error template key
onRequestContent	500	The body content cannot be transformed.
onResponseContent	500	The body content cannot be transformed.
onMessageRequest	400	The body content cannot be transformed.
onMessageResponse	500	The body content cannot be transformed.

Changelogs

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