Dynamic routing policy

Phase

onRequest	onResponse
X

Description

The dynamic-routing policy is used to dispatch inbound calls to different targets / endpoints or to rewrite URIs.

This policy is particularly useful for creating API Mashups.

Another typical use case is defining this kind of routing:

• Requests from http://gateway/apis/store/12/info are redirected to http://backend_store12/info

• Requests from http://gateway/apis/store/45/info are redirected to http://backend_store45/info

Attributes

Name	Description
request.endpoint	The endpoint URL invoked by the gateway after dynamic routing

Configuration

You can configure multiple rules and their respective redirections relative to the initial request path.

Warning

When you define rules, it is important to remember that the API context-path must not be part of the rule’s path. For example, if your context-path is /myapi and your call is /myapi/123, if you want to select 123 the regular expression is /(.*) (don’t forget the /).

Regular expressions

Using regular expressions can be very useful when you want to capture some parts of the initial request path and reuse them to define the redirection.

For example, to capture the end of a path after /v1/stores/, the rule path is /v1/stores/(.*). You can then use it in the redirect to property: http://store_backend/stores/{#group[[0]]}

You can also use named groups instead of indexed groups: /api/(?<version>v[0-9]+)/stores.* ⇒ http://host1/products/api/{#groupName['version']}

Examples

"dynamic-routing": {
    "rules": [
        {
            "pattern": "/v1/stores/(.*)",
            "url": "http://host2/stores/{#group[0]}"
        }
    ]
}

You can also select endpoints configured for your API by name using expression language:

"dynamic-routing": {
    "rules": [
        {
            "pattern": "/v1/stores/(.*)",
            "url": "{#endpoints['default']}/{#group[0]}"
        }
    ]
}

Errors

HTTP status code

Code	Message
400	When no rules match the inbound request