Kong-plugin-template-transformer

This is a Kong middleware to transform requests / responses, using pre-configured templates. This plugin has been tested to work along with kong >= 2.6.x, for a legacy version of this plugin, please check this link.

The Problem

When using Kong, you can create routes that proxy to an upstream. The problem lies when the upstream has an ugly response/request contract. Sometimes the kong bundled request transformer is not enough. This plugin was created for those situations, it can apply a template to JSON requests and responses, transforming them pretty much however you like.

Project Structure

The plugin folder should contain at least a schema.lua and a handler.lua, alongside with a spec folder and a .rockspec file specifying the current version of the package.

Writing Templates

We use lua-resty-template to write templates. It's also very important that you don't leave any \t in the files. We also only support JSON requests and responses for now.

Examples

Inside kong-plugin-template-transformer/template-transformer/validator/json/examples you'll find some examples for json templates and request files.

Rockspec Format

The .rockspec file should follow LuaRocks' conventions

Configuration

Enabling the plugin on a Route

Configure this plugin on a Route with:

curl -X POST http://kong:8001/routes/{route_id}/plugins \
    --data "name=kong-plugin-template-transformer"  \
    --data "config.request_template=http://new-url.com"
    --data "config.response_template=http://new-url.com"
    --data "config.hidden_fields=http://new-url.com"

• route_id: the id of the Route that this plugin configuration will target.
• config.request_template: Optional, the template to be applied before proxying to the upstream.
• config.response_template: Optional, the template to be applied before returning to the client.
• config.hidden_fields: Optional, a list of request or response fields that you do not want Kong to save them in a log file.

Developing

Build a new version

docker compose up -d
docker compose exec kong bash
make setup
make package

Credits

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