message-filtering.md

description
This page provides the technical details of the Message Filtering policy

Message Filtering

{% hint style="warning" %} This feature requires Gravitee's Enterprise Edition. {% endhint %}

Overview

The message-filtering policy enables the API publisher to create and enforce a filter that controls which messages are streamed to the subscriber/consumer, given a defined set of criteria.

Functional and implementation information for the message-filtering policy is organized into the following sections:

• Examples
• Configuration
• Changelogs

Examples

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

{% tabs %} {% tab title="Message API example" %} If this is my message:

{
    "productId": "1234",
    "value": "any value"
}

I will be able to filter any messages according to subscriptions metadata productId by configuring the policy as follows:

 {
    "name": "Products filter",
    "description": "Filter messages based on subscription product id",
    "enabled": true,
    "policy": "message-filtering",
    "configuration": {
        "filter": "#jsonPath(#message.content, '$.productId') == '#subscription.metadata.productId'"
    }
}

{% endtab %} {% endtabs %}

Configuration

Sample policy configuration:

{% code title="Sample Configuration" %}

{
  "name": "Message filtering",
  "description": "Apply filter to messages",
  "enabled": true,
  "policy": "message-filtering",
  "configuration": {
    "filter": "{#jsonPath(#message.content, '$.feature') == #subscription.metadata.feature}"
  }
}

{% endcode %}

Phases

The phases checked below are supported by the message-filtering policy:

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

Options

You can configure the message-filtering policy with the following options:

Property	Required	Description	Type	Default
filter	true	The filter's rule	string	-

Changelogs

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