Response headers

Use the ResponseHeaderModifier filter to add, append, overwrite, or remove headers from a response before it is sent back to the client.

For more information, see the HTTPHeaderFilter specification.

Before you begin

1. Set up an agentgateway proxy.
2. Install the httpbin sample app.

Add response headers

Add headers to incoming requests before they are sent back to the client. If the response already has the header set, the value of the header in the ResponseHeaderModifier filter is appended to the value of the header in the response.

1. Set up a header modifier that adds a my-response: hello response header.

   kubectl apply -f- <<EOF
   apiVersion: gateway.networking.k8s.io/v1
   kind: HTTPRoute
   metadata:
     name: httpbin-headers
     namespace: httpbin
   spec:
     parentRefs:
     - name: agentgateway-proxy
       namespace: agentgateway-system
     hostnames:
       - headers.example
     rules:
       - filters:
           - type: ResponseHeaderModifier
             responseHeaderModifier:
               add: 
               - name: my-response
                 value: hello
         backendRefs:
           - name: httpbin
             port: 8000
   EOF

   Setting	Description
   spec.parentRefs	The name and namespace of the gateway that serves this HTTPRoute. In this example, you use the agentgateway-proxy gateway that was created as part of the get started guide.
   spec.rules.filters.type	The type of filter that you want to apply to incoming requests. In this example, the ResponseHeaderModifier filter is used.
   spec.rules.filters.responseHeaderModifier.add	The name and value of the response header that you want to add.
   spec.rules.backendRefs	The backend destination you want to forward traffic to. In this example, all traffic is forwarded to the httpbin app that you set up as part of the get started guide.

2. Send a request to the httpbin app on the headers.example domain. Verify that you get back a 200 HTTP response code and that you see the my-response header in the response.

   Cloud Provider LoadbalancerPort-forward for local testing

   curl -vi http://$INGRESS_GW_ADDRESS:80/response-headers -H "host: headers.example:80"

   curl -vi localhost:8080/response-headers -H "host: headers.example"

   Example output:

   1 2 3 4 5 6 7 8 9 10 11 12 13

   * Mark bundle as not supporting multiuse < HTTP/1.1 200 OK HTTP/1.1 200 OK < access-control-allow-credentials: true access-control-allow-credentials: true < access-control-allow-origin: * access-control-allow-origin: * < content-type: application/json; encoding=utf-8 content-type: application/json; encoding=utf-8 < content-length: 3 content-length: 3 < my-response: hello my-response: hello

3. Optional: Remove the resources that you created.

   kubectl delete httproute httpbin-headers -n httpbin

Set response headers

Setting headers is similar to adding headers. If the response does not include the header, it is added by the ResponseHeaderModifier filter. However, if the request already contains the header, its value is overwritten with the value from the ResponseHeaderModifier filter.

1. Set up a header modifier that sets a my-response: custom response header.

   kubectl apply -f- <<EOF
   apiVersion: gateway.networking.k8s.io/v1
   kind: HTTPRoute
   metadata:
     name: httpbin-headers
     namespace: httpbin
   spec:
     parentRefs:
     - name: agentgateway-proxy
       namespace: agentgateway-system
     hostnames:
       - headers.example
     rules:
       - filters:
           - type: ResponseHeaderModifier
             responseHeaderModifier:
               set: 
               - name: my-response
                 value: custom
         backendRefs:
           - name: httpbin
             port: 8000
   EOF

   Setting	Description
   spec.parentRefs	The name and namespace of the gateway that serves this HTTPRoute. In this example, you use the agentgateway-proxy Gateway that was created as part of the get started guide.
   spec.rules.filters.type	The type of filter that you want to apply to incoming requests. In this example, the ResponseHeaderModifier filter is used.
   spec.rules.filters.responseHeaderModifier.set	The name and value of the response header that you want to set.
   spec.rules.backendRefs	The backend destination you want to forward traffic to. In this example, all traffic is forwarded to the httpbin app that you set up as part of the get started guide.

2. Send a request to the httpbin app on the headers.example domain. Verify that you get back a 200 HTTP response code and that the my-response: custom header was set.

   Cloud Provider LoadbalancerPort-forward for local testing

   curl -vi http://$INGRESS_GW_ADDRESS:80/response-headers -H "host: headers.example:80"

   curl -vi localhost:8080/response-headers -H "host: headers.example"

   Example output:

   1 2 3 4 5 6 7 8 9 10 11

   ... * Request completely sent off < HTTP/1.1 200 OK HTTP/1.1 200 OK < access-control-allow-credentials: true access-control-allow-credentials: true < access-control-allow-origin: * access-control-allow-origin: * ... < my-response: custom my-response: custom

3. Optional: Remove the resources that you created.

   kubectl delete httproute httpbin-headers -n httpbin

Remove response headers

You can remove HTTP headers from a response before the response is sent back to the client.

1. Send a request to the httpbin app and find the content-type header.

   Cloud Provider LoadbalancerPort-forward for local testing

   curl -vi http://$INGRESS_GW_ADDRESS:8080/response-headers -H "host: www.example.com:8080"

   curl -vi localhost:8080/response-headers -H "host: www.example.com"

   Example output:

   1 2 3 4 5 6 7 8 9 10 11 12

   ... * Mark bundle as not supporting multiuse < HTTP/1.1 200 OK HTTP/1.1 200 OK < access-control-allow-credentials: true access-control-allow-credentials: true < access-control-allow-origin: * access-control-allow-origin: * < content-type: application/json; encoding=utf-8 content-type: application/json; encoding=utf-8 < content-length: 3 content-length: 3

2. Set up a header modifier that removes the content-type header from the response.

   kubectl apply -f- <<EOF
   apiVersion: gateway.networking.k8s.io/v1
   kind: HTTPRoute
   metadata:
     name: httpbin-headers
     namespace: httpbin
   spec:
     parentRefs:
     - name: agentgateway-proxy
       namespace: agentgateway-system
     hostnames:
       - headers.example
     rules:
       - filters:
           - type: ResponseHeaderModifier
             responseHeaderModifier:
               remove: 
               - content-type
         backendRefs:
           - name: httpbin
             port: 8000
   EOF

   Setting	Description
   spec.parentRefs	The name and namespace of the gateway that serves this HTTPRoute. In this example, you use the agentgateway-proxy gateway that was created as part of the get started guide.
   spec.rules.filters.type	The type of filter that you want to apply. In this example, the ResponseHeaderModifier filter is used.
   spec.rules.filters.responseHeaderModifier.remove	The name of the response header that you want to remove.
   spec.rules.backendRefs	The backend destination you want to forward traffic to. In this example, all traffic is forwarded to the httpbin app that you set up as part of the get started guide.

3. Send a request to the httpbin app on the headers.example domain . Verify that the content-type response header is removed.

   Cloud Provider LoadbalancerPort-forward for local testing

   curl -vi http://$INGRESS_GW_ADDRESS:8080/response-headers -H "host: headers.example:8080"

   curl -vi localhost:8080/response-headers -H "host: headers.example"

   Example output:

   * Mark bundle as not supporting multiuse
   < HTTP/1.1 200 OK
   HTTP/1.1 200 OK
   < access-control-allow-credentials: true
   access-control-allow-credentials: true
   < access-control-allow-origin: *
   access-control-allow-origin: *
   < content-length: 3
   content-length: 3

4. Optional: Remove the resource that you created.

   kubectl delete httproute httpbin-headers -n httpbin