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Response headers

Use the K8sGateway VirtualHostOption or RouteOption resources to add or remove response headers for a specific route or all routes that the gateway serves.

For more information, see the Header manipulation API.

Before you begin

  1. Follow the Get started guide to install K8sGateway, set up a gateway resource, and deploy the httpbin sample app.

  2. Get the external address of the gateway and save it in an environment variable.

    export INGRESS_GW_ADDRESS=$(kubectl get svc -n gloo-system gloo-proxy-http -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")
    echo $INGRESS_GW_ADDRESS  
    kubectl port-forward deployment/gloo-proxy-http -n gloo-system 8080:8080

Add response headers

Add response headers to responses before they are sent back to the client.

Use a VirtualHostOption resource to add response headers for responses from all routes that the gateway serves.

  1. Create a VirtualHostOption custom resource to specify your header manipulation rules. In the following example, the my-header: gloo-gateway header is added to each response.

    kubectl apply -n gloo-system -f- <<EOF
    apiVersion: gateway.solo.io/v1
    kind: VirtualHostOption
    metadata:
      name: header-manipulation
      namespace: gloo-system
    spec:
      options:
        headerManipulation:
          responseHeadersToAdd: 
            - header:
                key: "my-header"
                value: "gloo-gateway"
      targetRefs:
        group: gateway.networking.k8s.io
        kind: Gateway
        name: http
        namespace: gloo-system
    EOF
  2. Send a request to the httpbin app and verify that the my-header header is added to the response.

    • LoadBalancer IP address or hostname
      curl -vik http://$INGRESS_GW_ADDRESS:8080/response-headers -H "host: www.example.com:8080"
    • Port-forward for local testing
      curl -vik localhost:8080/response-headers -H "host: www.example.com"

    Example output:

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    * 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
    < date: Fri, 19 Apr 2024 13:26:23 GMT
    date: Fri, 19 Apr 2024 13:26:23 GMT
    < content-length: 3
    content-length: 3
    < x-envoy-upstream-service-time: 0
    x-envoy-upstream-service-time: 0
    < my-header: gloo-gateway
    my-header: gloo-gateway
    < server: envoy
    server: envoy
  3. Optional: Clean up the resources that you created.

    kubectl delete virtualhostoption header-manipulation -n gloo-system

Use a RouteOption resource to add response headers to responses from a specific route.

  1. Create a RouteOption custom resource to specify your header manipulation rules. In the following example, the my-response: gloo-gateway header is added to each response.

    kubectl apply -n httpbin -f- <<EOF
    apiVersion: gateway.solo.io/v1
    kind: RouteOption
    metadata:
      name: header-manipulation
      namespace: httpbin
    spec:
      options:
        headerManipulation:
          responseHeadersToAdd:
            - header:
                key: "my-response"
                value: "gloo-gateway"
    EOF
  2. Create an HTTPRoute resource for the httpbin app that references the RouteOptions that you just created.

    kubectl apply -f- <<EOF
    apiVersion: gateway.networking.k8s.io/v1
    kind: HTTPRoute
    metadata:
      name: httpbin-headers
      namespace: httpbin
    spec:
      parentRefs:
      - name: http
        namespace: gloo-system
      hostnames:
        - headers.example
      rules:
        - filters:
            - type: ExtensionRef
              extensionRef:
                group: gateway.solo.io
                kind: RouteOption
                name: header-manipulation
          backendRefs:
            - name: httpbin
              port: 8000
    EOF
  3. 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.

    • LoadBalancer IP address or hostname
      curl -vik http://$INGRESS_GW_ADDRESS:8080/response-headers -H "host: headers.example:8080"
    • Port-forward for local testing
      curl -vik localhost:8080/response-headers -H "host: headers.example"

    Example output:

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    * 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
    < date: Fri, 19 Apr 2024 02:23:58 GMT
    date: Fri, 19 Apr 2024 02:23:58 GMT
    < content-length: 3
    content-length: 3
    < x-envoy-upstream-service-time: 0
    x-envoy-upstream-service-time: 0
    < my-response: gloo-gateway
    my-response: gloo-gateway
    < server: envoy
    server: envoy
  4. Optional: Remove the resources that you created.

    kubectl delete httproute httpbin-headers -n httpbin
    kubectl delete routeoption header-manipulation -n httpbin

Remove response headers

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

Remove specific headers from all responses from the routes that the gateway serves.

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

    • LoadBalancer IP address or hostname
      curl -vik http://$INGRESS_GW_ADDRESS:8080/response-headers -H "host: www.example.com:8080"
    • Port-forward for local testing
      curl -vik localhost:8080/response-headers -H "host: www.example.com"

    Example output:

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    ...
    * 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
    < date: Fri, 19 Apr 2024 13:37:36 GMT
    date: Fri, 19 Apr 2024 13:37:36 GMT
    < content-length: 3
    content-length: 3
    < x-envoy-upstream-service-time: 0
    x-envoy-upstream-service-time: 0
    < server: envoy
    server: envoy
  2. Create a VirtualHostOption custom resource to specify your header manipulation rules. In the following example, the content-length header is removed from each response.

    kubectl apply -n gloo-system -f- <<EOF
    apiVersion: gateway.solo.io/v1
    kind: VirtualHostOption
    metadata:
      name: header-manipulation
      namespace: gloo-system
    spec:
      options:
        headerManipulation:
          responseHeadersToRemove: ["content-length"] 
      targetRefs:
        group: gateway.networking.k8s.io
        kind: Gateway
        name: http
        namespace: gloo-system
    EOF
  3. Send a request to the httpbin app and verify that the content-length header is removed from the response.

    • LoadBalancer IP address or hostname
      curl -vik http://$INGRESS_GW_ADDRESS:8080/response-headers -H "host: www.example.com:8080"
    • Port-forward for local testing
      curl -vik localhost:8080/response-headers -H "host: www.example.com"

    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-type: application/json; encoding=utf-8
    content-type: application/json; encoding=utf-8
    < date: Fri, 19 Apr 2024 13:51:53 GMT
    date: Fri, 19 Apr 2024 13:51:53 GMT
    < x-envoy-upstream-service-time: 0
    x-envoy-upstream-service-time: 0
    < server: envoy
    server: envoy
    < transfer-encoding: chunked
    transfer-encoding: chunked
    
  4. Optional: Clean up the resources that you created.

    kubectl delete virtualhostoption header-manipulation -n gloo-system

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

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

    • LoadBalancer IP address or hostname
      curl -vik http://$INGRESS_GW_ADDRESS:8080/response-headers -H "host: www.example.com:8080"
    • Port-forward for local testing
      curl -vik localhost:8080/response-headers -H "host: www.example.com"

    Example output:

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    ...
    * 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
    < date: Fri, 19 Apr 2024 16:40:01 GMT
    date: Fri, 19 Apr 2024 16:40:01 GMT
    < content-length: 3
    content-length: 3
    < x-envoy-upstream-service-time: 0
    x-envoy-upstream-service-time: 0
    < server: envoy
    server: envoy
  2. Create a RouteOption resource to specify your header manipulation rules. In this example, you remove the content-length response header from each response.

    kubectl apply -n httpbin -f- <<EOF
    apiVersion: gateway.solo.io/v1
    kind: RouteOption
    metadata:
      name: header-manipulation
      namespace: httpbin
    spec:
      options:
        headerManipulation:
          responseHeadersToRemove: ["content-length"]
    EOF
  3. Create an HTTPRoute resource for the httpbin app that references the RouteOptions that you just created.

    kubectl apply -f- <<EOF
    apiVersion: gateway.networking.k8s.io/v1
    kind: HTTPRoute
    metadata:
      name: httpbin-headers
      namespace: httpbin
    spec:
      parentRefs:
      - name: http
        namespace: gloo-system
      hostnames:
        - headers.example
      rules:
        - filters:
            - type: ExtensionRef
              extensionRef:
                group: gateway.solo.io
                kind: RouteOption
                name: header-manipulation
          backendRefs:
            - name: httpbin
              port: 8000
    EOF
  4. Send a request to the httpbin app on the headers.example domain . Verify that the content-length response header is removed.

    • LoadBalancer IP address or hostname
      curl -vik http://$INGRESS_GW_ADDRESS:8080/response-headers -H "host: headers.example:8080"
    • Port-forward for local testing
      curl -vik localhost:8080/reesponse-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-type: application/json; encoding=utf-8
    content-type: application/json; encoding=utf-8
    < date: Fri, 19 Apr 2024 13:51:53 GMT
    date: Fri, 19 Apr 2024 13:51:53 GMT
    < x-envoy-upstream-service-time: 0
    x-envoy-upstream-service-time: 0
    < server: envoy
    server: envoy
    < transfer-encoding: chunked
    transfer-encoding: chunked
    
  5. Optional: Remove the resources that you created.

    kubectl delete httproute httpbin-headers -n httpbin
    kubectl delete routeoption header-manipulation -n httpbin