Request Transformer plugin

Transform the request sent by a client on the fly on Kong, before hitting the upstream server.

Note: The functionality of this plugin as bundled with versions of Kong prior to 0.10.0 differs from what is documented herein. Refer to the CHANGELOG for details.

Configuration Reference

You can configure this plugin using the Kong Admin API or through declarative configuration, which involves directly editing the Kong configuration file.

Enabling the plugin on a Service

Kong Admin API

Kubernetes

Declarative (YAML)

For example, configure this plugin on a Service by making the following request:

$ curl -X POST http://<admin-hostname>:8001/services/<service>/plugins \
    --data "name=request-transformer"  \
    --data "config.remove.headers=x-toremove, x-another-one" \
    --data "config.remove.querystring=qs-old-name:qs-new-name, qs2-old-name:qs2-new-name" \
    --data "config.remove.body=formparam-toremove, formparam-another-one" \
    --data "config.rename.headers=header-old-name:header-new-name, another-old-name:another-new-name" \
    --data "config.rename.querystring=qs-old-name:qs-new-name, qs2-old-name:qs2-new-name" \
    --data "config.rename.body=param-old:param-new, param2-old:param2-new" \
    --data "config.append.headers=x-existing-header:some_value, x-another-header:some_value" \
    --data "config.add.headers=x-new-header:value,x-another-header:something" \
    --data "config.add.querystring=new-param:some_value, another-param:some_value" \
    --data "config.add.body=new-form-param:some_value, another-form-param:some_value"

First, create a KongPlugin resource:

apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
  name: <request-transformer-example>
config: 
  remove:
    headers: x-toremove, x-another-one
  remove:
    querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
  remove:
    body: formparam-toremove, formparam-another-one
  rename:
    headers: header-old-name:header-new-name, another-old-name:another-new-name
  rename:
    querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
  rename:
    body: param-old:param-new, param2-old:param2-new
  append:
    headers: x-existing-header:some_value, x-another-header:some_value
  add:
    headers: x-new-header:value,x-another-header:something
  add:
    querystring: new-param:some_value, another-param:some_value
  add:
    body: new-form-param:some_value, another-form-param:some_value
plugin: request-transformer

Next, apply the KongPlugin resource to a Service by annotating the Service as follows:

apiVersion: v1
kind: Service
metadata:
  name: <service>
  labels:
    app: <service>
  annotations:
    konghq.com/plugins: <request-transformer-example>
spec:
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP
    name: <service>
  selector:
    app: <service>

Note: The KongPlugin resource only needs to be defined once and can be applied to any Service, Consumer, or Route in the namespace. If you want the plugin to be available cluster-wide, create the resource as a KongClusterPlugin instead of KongPlugin.

For example, configure this plugin on a Service by adding this section to your declarative configuration file:

plugins:
- name: request-transformer
  service: <service>
  config: 
    remove:
      headers: x-toremove, x-another-one
    remove:
      querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
    remove:
      body: formparam-toremove, formparam-another-one
    rename:
      headers: header-old-name:header-new-name, another-old-name:another-new-name
    rename:
      querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
    rename:
      body: param-old:param-new, param2-old:param2-new
    append:
      headers: x-existing-header:some_value, x-another-header:some_value
    add:
      headers: x-new-header:value,x-another-header:something
    add:
      querystring: new-param:some_value, another-param:some_value
    add:
      body: new-form-param:some_value, another-form-param:some_value

<service> is the id or name of the Service that this plugin configuration will target.

Note: The legacy API entity has been deprecated in favor of Services since CE 0.13.0 and EE 0.32.

Enabling the plugin on a Route

Kong Admin API

Kubernetes

Declarative (YAML)

For example, configure this plugin on a Route with:

$ curl -X POST http://<admin-hostname>:8001/routes/<route>/plugins \
    --data "name=request-transformer"  \
    --data "config.remove.headers=x-toremove, x-another-one" \
    --data "config.remove.querystring=qs-old-name:qs-new-name, qs2-old-name:qs2-new-name" \
    --data "config.remove.body=formparam-toremove, formparam-another-one" \
    --data "config.rename.headers=header-old-name:header-new-name, another-old-name:another-new-name" \
    --data "config.rename.querystring=qs-old-name:qs-new-name, qs2-old-name:qs2-new-name" \
    --data "config.rename.body=param-old:param-new, param2-old:param2-new" \
    --data "config.append.headers=x-existing-header:some_value, x-another-header:some_value" \
    --data "config.add.headers=x-new-header:value,x-another-header:something" \
    --data "config.add.querystring=new-param:some_value, another-param:some_value" \
    --data "config.add.body=new-form-param:some_value, another-form-param:some_value"

First, create a KongPlugin resource:

apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
  name: <request-transformer-example>
config: 
  remove:
    headers: x-toremove, x-another-one
  remove:
    querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
  remove:
    body: formparam-toremove, formparam-another-one
  rename:
    headers: header-old-name:header-new-name, another-old-name:another-new-name
  rename:
    querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
  rename:
    body: param-old:param-new, param2-old:param2-new
  append:
    headers: x-existing-header:some_value, x-another-header:some_value
  add:
    headers: x-new-header:value,x-another-header:something
  add:
    querystring: new-param:some_value, another-param:some_value
  add:
    body: new-form-param:some_value, another-form-param:some_value
plugin: request-transformer

Then, apply it to an ingress (Route or Routes) by annotating the ingress as follows:

apiVersion: networking/v1beta1
kind: Ingress
metadata:
  name: <route>
  annotations:
    kubernetes.io/ingress.class: kong
    konghq.com/plugins: <request-transformer-example>
spec:
  rules:
  - host: examplehostname.com
    http:
      paths:
      - path: /bar
        backend:
          serviceName: echo
          servicePort: 80

For example, configure this plugin on a Route by adding this section to your declarative configuration file:

plugins:
- name: request-transformer
  route: <route>
  config: 
    remove:
      headers: x-toremove, x-another-one
    remove:
      querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
    remove:
      body: formparam-toremove, formparam-another-one
    rename:
      headers: header-old-name:header-new-name, another-old-name:another-new-name
    rename:
      querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
    rename:
      body: param-old:param-new, param2-old:param2-new
    append:
      headers: x-existing-header:some_value, x-another-header:some_value
    add:
      headers: x-new-header:value,x-another-header:something
    add:
      querystring: new-param:some_value, another-param:some_value
    add:
      body: new-form-param:some_value, another-form-param:some_value

<route> is the id or name of the Route that this plugin configuration will target.

Enabling the plugin on a Consumer

Kong Admin API

Kubernetes

Declarative (YAML)

For example, configure this plugin on a Consumer with:

$ curl -X POST http://<admin-hostname>:8001/consumers/<consumer>/plugins \
    --data "name=request-transformer"  \
    --data "config.remove.headers=x-toremove, x-another-one" \
    --data "config.remove.querystring=qs-old-name:qs-new-name, qs2-old-name:qs2-new-name" \
    --data "config.remove.body=formparam-toremove, formparam-another-one" \
    --data "config.rename.headers=header-old-name:header-new-name, another-old-name:another-new-name" \
    --data "config.rename.querystring=qs-old-name:qs-new-name, qs2-old-name:qs2-new-name" \
    --data "config.rename.body=param-old:param-new, param2-old:param2-new" \
    --data "config.append.headers=x-existing-header:some_value, x-another-header:some_value" \
    --data "config.add.headers=x-new-header:value,x-another-header:something" \
    --data "config.add.querystring=new-param:some_value, another-param:some_value" \
    --data "config.add.body=new-form-param:some_value, another-form-param:some_value"

You can combine consumer.id, service.id, or route.id in the same request, to further narrow the scope of the plugin.

First, create a KongPlugin resource:

apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
  name: <request-transformer-example>
config: 
  remove:
    headers: x-toremove, x-another-one
  remove:
    querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
  remove:
    body: formparam-toremove, formparam-another-one
  rename:
    headers: header-old-name:header-new-name, another-old-name:another-new-name
  rename:
    querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
  rename:
    body: param-old:param-new, param2-old:param2-new
  append:
    headers: x-existing-header:some_value, x-another-header:some_value
  add:
    headers: x-new-header:value,x-another-header:something
  add:
    querystring: new-param:some_value, another-param:some_value
  add:
    body: new-form-param:some_value, another-form-param:some_value
plugin: request-transformer

Then, apply it to a Consumer by annotating the KongConsumer resource as follows:

apiVersion: configuration.konghq.com/v1
kind: KongConsumer
metadata:
  name: <consumer>
  annotations:
    konghq.com/plugins: <request-transformer-example>
    kubernetes.io/ingress.class: kong

For example, configure this plugin on a Consumer by adding this section to your declarative configuration file:

plugins:
- name: request-transformer
  consumer: <consumer>
  config: 
    remove:
      headers: x-toremove, x-another-one
    remove:
      querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
    remove:
      body: formparam-toremove, formparam-another-one
    rename:
      headers: header-old-name:header-new-name, another-old-name:another-new-name
    rename:
      querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
    rename:
      body: param-old:param-new, param2-old:param2-new
    append:
      headers: x-existing-header:some_value, x-another-header:some_value
    add:
      headers: x-new-header:value,x-another-header:something
    add:
      querystring: new-param:some_value, another-param:some_value
    add:
      body: new-form-param:some_value, another-form-param:some_value

<consumer> is the id or username of the Consumer that this plugin configuration will target.

Enabling the plugin globally

A plugin which is not associated to any Service, Route, or Consumer is considered global, and will be run on every request. Read the Plugin Reference and the Plugin Precedence sections for more information.

Kong Admin API

Kubernetes

Declarative (YAML)

For example, configure this plugin globally with:

$ curl -X POST http://<admin-hostname>:8001/plugins/ \
    --data "name=request-transformer"  \
    --data "config.remove.headers=x-toremove, x-another-one" \
    --data "config.remove.querystring=qs-old-name:qs-new-name, qs2-old-name:qs2-new-name" \
    --data "config.remove.body=formparam-toremove, formparam-another-one" \
    --data "config.rename.headers=header-old-name:header-new-name, another-old-name:another-new-name" \
    --data "config.rename.querystring=qs-old-name:qs-new-name, qs2-old-name:qs2-new-name" \
    --data "config.rename.body=param-old:param-new, param2-old:param2-new" \
    --data "config.append.headers=x-existing-header:some_value, x-another-header:some_value" \
    --data "config.add.headers=x-new-header:value,x-another-header:something" \
    --data "config.add.querystring=new-param:some_value, another-param:some_value" \
    --data "config.add.body=new-form-param:some_value, another-form-param:some_value"

Create a KongClusterPlugin resource and label it as global:

apiVersion: configuration.konghq.com/v1
kind: KongClusterPlugin
metadata:
  name: <global-request-transformer>
  annotations:
    kubernetes.io/ingress.class: kong
  labels:
    global: \"true\"
config: 
  remove:
    headers: x-toremove, x-another-one
  remove:
    querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
  remove:
    body: formparam-toremove, formparam-another-one
  rename:
    headers: header-old-name:header-new-name, another-old-name:another-new-name
  rename:
    querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
  rename:
    body: param-old:param-new, param2-old:param2-new
  append:
    headers: x-existing-header:some_value, x-another-header:some_value
  add:
    headers: x-new-header:value,x-another-header:something
  add:
    querystring: new-param:some_value, another-param:some_value
  add:
    body: new-form-param:some_value, another-form-param:some_value
plugin: request-transformer

For example, configure this plugin using the plugins: entry in the declarative configuration file:

plugins:
- name: request-transformer
  config: 
    remove:
      headers: x-toremove, x-another-one
    remove:
      querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
    remove:
      body: formparam-toremove, formparam-another-one
    rename:
      headers: header-old-name:header-new-name, another-old-name:another-new-name
    rename:
      querystring: qs-old-name:qs-new-name, qs2-old-name:qs2-new-name
    rename:
      body: param-old:param-new, param2-old:param2-new
    append:
      headers: x-existing-header:some_value, x-another-header:some_value
    add:
      headers: x-new-header:value,x-another-header:something
    add:
      querystring: new-param:some_value, another-param:some_value
    add:
      body: new-form-param:some_value, another-form-param:some_value

Parameters

Here's a list of all the parameters which can be used in this plugin's configuration:

Form Parameter	Description
`name` Type: string	The name of the plugin to use, in this case `request-transformer`.
`service.id` Type: string	The ID of the Service the plugin targets.
`route.id` Type: string	The ID of the Route the plugin targets.
`consumer.id` Type: string	The ID of the Consumer the plugin targets.
`enabled` Type: boolean Default value: `true`	Whether this plugin will be applied.
`api_id` Type: string	The ID of the API the plugin targets. Note: The API Entity is deprecated in favor of Services since CE 0.13.0 and EE 0.32.
`config.http_method` optional	Changes the HTTP method for the upstream request.
`config.remove.headers` optional	List of header names. Unset the header(s) with the given name.
`config.remove.querystring` optional	List of querystring names. Remove the querystring if it is present.
`config.remove.body` optional	List of parameter names. Remove the parameter if and only if content-type is one the following [`application/json`, `multipart/form-data`, `application/x-www-form-urlencoded`] and parameter is present.
`config.replace.headers` optional	List of headername:value pairs. If and only if the header is already set, replace its old value with the new one. Ignored if the header is not already set.
`config.replace.querystring` optional	List of queryname:value pairs. If and only if the field name is already set, replace its old value with the new one. Ignored if the field name is not already set.
`config.rename.headers` optional	List of headername:value pairs. If and only if the header is already set, rename the header. The value is unchanged. Ignored if the header is not already set.
`config.rename.querystring` optional	List of queryname:value pairs. If and only if the field name is already set, rename the field name. The value is unchanged. Ignored if the field name is not already set.
`config.rename.body` optional	List of parameter name:value pairs. Rename the parameter name if and only if content-type is one the following [`application/json`, `multipart/form-data`, `application/x-www-form-urlencoded`] and parameter is present.
`config.append.headers` optional	List of headername:value pairs. If the header is not set, set it with the given value. If it is already set, a new header with the same name and the new value will be set.
`config.replace.body` optional	List of paramname:value pairs. If and only if content-type is one the following [`application/json`, `multipart/form-data`, `application/x-www-form-urlencoded`] and the parameter is already present, replace its old value with the new one. Ignored if the parameter is not already present.
`config.add.headers` optional	List of headername:value pairs. If and only if the header is not already set, set a new header with the given value. Ignored if the header is already set.
`config.add.querystring` optional	List of queryname:value pairs. If and only if the querystring is not already set, set a new querystring with the given value. Ignored if the header is already set.
`config.add.body` optional	List of pramname:value pairs. If and only if content-type is one the following [`application/json`, `multipart/form-data`, `application/x-www-form-urlencoded`] and the parameter is not present, add a new parameter with the given value to form-encoded body. Ignored if the parameter is already present.
`config.append.headers` optional	List of headername:value pairs. If the header is not set, set it with the given value. If it is already set, an additional new header with the same name and the new value will be appended.
`config.append.querystring` optional	List of queryname:value pairs. If the querystring is not set, set it with the given value. If it is already set, a new querystring with the same name and the new value will be set.
`config.append.body` optional	List of paramname:value pairs. If the content-type is one the following [`application/json`, `application/x-www-form-urlencoded`], add a new parameter with the given value if the parameter is not present, otherwise if it is already present, the two values (old and new) will be aggregated in an array.

Note: if the value contains a , then the comma-separated format for lists cannot be used. The array notation must be used instead.

Dynamic Transformation Based on Request Content

The Request Transformer plugin bundled with Kong Enterprise Edition allows for adding or replacing content in the upstream request based on variable data found in the client request, such as request headers, query string parameters, or URI parameters as defined by a URI capture group.

If you already are a Kong Enterprise customer, you can request access to this plugin functionality by opening a support ticket using your Enterprise support channels.

If you are not a Kong Enterprise customer, you can inquire about our Enterprise offering by contacting us.

Order of execution

Plugin performs the response transformation in following order

remove –> rename –> replace –> add –> append

Examples

In these examples we have the plugin enabled on a Service. This would work similarly for Routes, or the depreciated API entity.

Add multiple headers by passing each header:value pair separately:

$ curl -X POST http://localhost:8001/services/example-service/plugins \
  --data "name=request-transformer" \
  --data "config.add.headers[1]=h1:v1" \
  --data "config.add.headers[2]=h2:v1"

incoming request headers	upstream proxied headers:
h1: v1	h1: v1 h2: v1

Add multiple headers by passing comma separated header:value pair:

$ curl -X POST http://localhost:8001/services/example-service/plugins \
  --data "name=request-transformer" \
  --data "config.add.headers=h1:v1,h2:v2"

incoming request headers	upstream proxied headers:
h1: v1	h1: v1 h2: v1

Add multiple headers passing config as JSON body:

$ curl -X POST http://localhost:8001/services/example-service/plugins \
  --header 'content-type: application/json' \
  --data '{"name": "request-transformer", "config": {"add": {"headers": ["h1:v2", "h2:v1"]}}}'

incoming request headers	upstream proxied headers:
h1: v1	h1: v1 h2: v1

Add a querystring and a header:

$ curl -X POST http://localhost:8001/services/example-service/plugins \
  --data "name=request-transformer" \
  --data "config.add.querystring=q1:v2,q2:v1" \
  --data "config.add.headers=h1:v1"

incoming request headers	upstream proxied headers:
h1: v2	h1: v2 h2: v1
h3: v1	h1: v1 h2: v1 h3: v1

incoming request querystring	upstream proxied querystring
?q1=v1	?q1=v1&q2=v1
	?q1=v2&q2=v1

Append multiple headers and remove a body parameter:

$ curl -X POST http://localhost:8001/services/example-service/plugins \
  --header 'content-type: application/json' \
  --data '{"name": "request-transformer", "config": {"append": {"headers": ["h1:v2", "h2:v1"]}, "remove": {"body": ["p1"]}}}'

incoming request headers	upstream proxied headers:
h1: v1	h1: v1 h1: v2 h2: v1

incoming url encoded body	upstream proxied url encoded body:
p1=v1&p2=v1	p2=v1
p2=v1	p2=v1

About this Plugin
Made by
Categories	Transformations
Bundled with...
Kong Enterprise 0.34-x 0.33-x 0.32-x Kong Community 0.14.x 0.13.x 0.12.x 0.11.x 0.10.x 0.9.x 0.8.x 0.7.x 0.6.x 0.5.x 0.4.x 0.3.x