URL Rewrite

Overview

The URL Rewrite action allows you to transform the URL path and query parameters of the incoming request.

Example

Use this action config in your Traffic Policy

YAML

# snippet
---
actions:
  - type: "url-rewrite"
    config:
      format: "ngrok"
      from: "v0/user/([0-9]+).*&filter=(.*)"
      to: "v1/user?id=$1&filter=${req.query_params['filter'][0]}"

JSON

// snippet
{
  "actions": [
    {
      "type": "url-rewrite",
      "config": {
        "format": "ngrok",
        "from": "v0/user/([0-9]+).*&filter=(.*)",
        "to": "v1/user?id=$1&filter=${req.query_params['filter'][0]}"
      }
    }
  ]
}

Behavior

When executed, this action will replace all regex matches with the configured replacement. Before regex replacement, all cel expressions will be interpolated and replaced with their corresponding values.

Reference

Supported Directions

• Inbound

Configuration

Type
url-rewrite

Parameter		Description
from	string	A regular expression string to match inside of the URL. Supports interpolating the results of cel expressions outside of regex.
to	string	A regular expression string to replace the from match with. Supports interpolating the results of cel expressions outside of regex.
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: "url-rewrite"
    config:
      format: "ngrok"
      from: "/v0/api?lat=(${conn.geo.latitude})"
      to: "/v1/api?lat=$1&long=${conn.geo.longitude}"

JSON

// simple variable replacement
{
  "actions": [
    {
      "type": "url-rewrite",
      "config": {
        "format": "ngrok",
        "from": "/v0/api?lat=(${conn.geo.latitude})",
        "to": "/v1/api?lat=$1&long=${conn.geo.longitude}"
      }
    }
  ]
}

YAML

# regex and variable replacement
---
actions:
  - type: "url-rewrite"
    config:
      format: "ngrok"
      from: "/v0/api/(carmen)/sandiego?city=${conn.geo.city}"
      to: "/v1/api/$1/sandiego?found=${conn.geo.city}"

JSON

// regex and variable replacement
{
  "actions": [
    {
      "type": "url-rewrite",
      "config": {
        "format": "ngrok",
        "from": "/v0/api/(carmen)/sandiego?city=${conn.geo.city}",
        "to": "/v1/api/$1/sandiego?found=${conn.geo.city}"
      }
    }
  ]
}

YAML

# variable replacement with comparisons
---
actions:
  - type: "url-rewrite"
    config:
      format: "ngrok"
      from: "/v0/api/when-will-then-be-now?not-now=${conn.start_ts > time.now}"
      to: "/v1/api/soon?now=${conn.start_ts < time.now}"

JSON

// variable replacement with comparisons
{
  "actions": [
    {
      "type": "url-rewrite",
      "config": {
        "format": "ngrok",
        "from": "/v0/api/when-will-then-be-now?not-now=${conn.start_ts > time.now}",
        "to": "/v1/api/soon?now=${conn.start_ts < time.now}"
      }
    }
  ]
}