Redirect

Overview

The Redirect policy action enables transforming your URL using regular expressions and redirect through location header.

Example

Use this action config in your Traffic Policy

YAML

# snippet
---
actions:
  - type: "redirect"
    config:
      format: "ngrok"
      from: "v0/user/([0-9]+).*"
      to: "v1/user?id=$1&port=${conn.server_port}"
      status_code: 301
      headers:
        rewrite: "true"

JSON

// snippet
{
  "actions": [
    {
      "type": "redirect",
      "config": {
        "format": "ngrok",
        "from": "v0/user/([0-9]+).*",
        "to": "v1/user?id=$1&port=${conn.server_port}",
        "status_code": 301,
        "headers": {
          "rewrite": "true"
        }
      }
    }
  ]
}

Behavior

When executed this action will abort the request and replace all matches on the inbound URL with the configured replacements. Before regex replacement, all variables or expressions will be replaced with their corresponding values using cel expressions templating syntax.

Reference

Supported Directions

• Inbound

Configuration

Type
redirect

Parameter		Description
from	string	A regular expression string to match inside of the URL. Supports interpolating the results of cel expressions outside of regular regex.
to	string	A regular expression string to replace the from match with. Supports interpolating the results of cel expressions outside of regular regex.
status_code	int	3xx status code used for redirecting, 302 by default.
headers	Map<string, string>	Headers to be added to the request.
format	string	(default: ngrok) Determines interpolation format in to/from fields.

Templating Syntax

The results of CEL expressions can be interpolated into your policy's config using ngrok's ${} templating syntax. For a complete list of available variables and functions or to see a more detailed explanation, checkout the docs.

Templating Examples

YAML

# simple variable replacement
---
actions:
  - type: "redirect"
    config:
      format: "ngrok"
      to: "/v1/api/carmen/sandiego?found=${conn.geo.city}"
      status_code: 301
      headers:
        rewrite: "true"

JSON

// simple variable replacement
{
  "actions": [
    {
      "type": "redirect",
      "config": {
        "format": "ngrok",
        "to": "/v1/api/carmen/sandiego?found=${conn.geo.city}",
        "status_code": 301,
        "headers": {
          "rewrite": "true"
        }
      }
    }
  ]
}

YAML

# converting variables using cel expressions
---
actions:
  - type: "redirect"
    config:
      format: "ngrok"
      to: "/v1/api/soon?time=${string(conn.start_ts)}"
      status_code: 301
      headers:
        rewrite: "true"

JSON

// converting variables using cel expressions
{
  "actions": [
    {
      "type": "redirect",
      "config": {
        "format": "ngrok",
        "to": "/v1/api/soon?time=${string(conn.start_ts)}",
        "status_code": 301,
        "headers": {
          "rewrite": "true"
        }
      }
    }
  ]
}

YAML

# combining variables and regex capture groups
---
actions:
  - type: "redirect"
    config:
      format: "ngrok"
      to: "/v1/api?lat=$1&long=${conn.geo.longitude}"
      status_code: 301
      headers:
        rewrite: "true"

JSON

// combining variables and regex capture groups
{
  "actions": [
    {
      "type": "redirect",
      "config": {
        "format": "ngrok",
        "to": "/v1/api?lat=$1&long=${conn.geo.longitude}",
        "status_code": 301,
        "headers": {
          "rewrite": "true"
        }
      }
    }
  ]
}