PreserveCase插件

部署客户端应用

1. 部署客户端应用。

   kubectl apply -f - <<EOF
   apiVersion: v1
   kind: ServiceAccount
   metadata:
     name: sleep
   ---
   apiVersion: v1
   kind: Service
   metadata:
     name: sleep
     labels:
       app: sleep
       service: sleep
   spec:
     ports:
     - port: 80
       name: http
     selector:
       app: sleep
   ---
   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: sleep
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: sleep
     template:
       metadata:
         labels:
           app: sleep
       spec:
         terminationGracePeriodSeconds: 0
         serviceAccountName: sleep
         containers:
         - name: sleep
           image: registry.cn-hangzhou.aliyuncs.com/acs/curl:8.1.2
           command: ["/bin/sleep", "infinity"]
           imagePullPolicy: IfNotPresent
           volumeMounts:
           - mountPath: /etc/sleep/tls
             name: secret-volume
         volumes:
         - name: secret-volume
           secret:
             secretName: sleep-secret
             optional: true
   ---
   EOF

2. 查看客户端应用运行状态。

   kubectl get pod | grep sleep

   预期输出：

   sleep-77cb457458-c9mds        2/2     Running   0          10s

部署服务端应用

1. 部署服务端应用httpbin-echo，此应用会响应与请求相同的请求头。

   kubectl apply -f - <<EOF
   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: http-echo
     labels:
       app: http-echo
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: http-echo
     template:
       metadata:
         labels:
           app: http-echo
       spec:
         containers:
         - name: http-echo
           image: registry-cn-hangzhou.ack.aliyuncs.com/dev/http-echo:latest
           ports:
           - containerPort: 8080
   ---
   apiVersion: v1
   kind: Service
   metadata:
     name: http-echo
   spec:
     selector:
       app: http-echo
     ports:
       - protocol: TCP
         port: 80
         targetPort: 8080
         name: http
     type: ClusterIP
   EOF

2. 查看服务端应用运行状态。

   kubectl get pod | grep http-echo

   预期输出：

   http-echo-89d9b457f-pcctg     2/2     Running   0          20s

验证请求头大小写保持

从客户端向服务端发起请求。

kubectl exec -it deploy/sleep -- curl http-echo -H 'X-TEST: test'

预期输出：

GET / HTTP/1.1
host: http-echo
user-agent: curl/8.1.2
accept: */*
x-test: test

可以看到，x-test请求头被强制转成了小写。

验证响应体大小写保持

从客户端向服务端发起请求。

kubectl exec -it deploy/sleep -- curl http-echo -I

预期输出：

HTTP/1.1 200 OK
content-type: text/plain; charset=utf-8
content-length: 476
x-envoy-upstream-service-time: 7
date: Tue, 19 Aug 2025 06:33:51 GMT
server: envoy

可以看到，经过Envoy后的请求头中的content-type和content-length被转换为了小写。

启用请求头大小写保持能力

您可以通过启用此插件或在控制台启用请求头大小写保持的能力。若您采用在控制台方式使用此能力，您还需要手动重启应用使能力生效。

kubectl rollout restart deploy/http-echo deploy/sleep

再次验证

1. 验证请求头大小写保持。

   kubectl exec -it deploy/sleep -- curl http-echo -H 'X-TEST: test'

   预期输出：

   GET / HTTP/1.1
   Host: http-echo
   User-Agent: curl/8.1.2
   Accept: */*
   X-TEST: test

   可以看到，X-TEST请求头仍然保持了大写。

2. 验证响应大小写保持。

   kubectl exec -it deploy/sleep -- curl http-echo -I

   预期输出：

   HTTP/1.1 200 OK
   Content-Type: text/plain; charset=utf-8
   Content-Length: 476
   x-envoy-upstream-service-time: 1
   date: Tue, 19 Aug 2025 06:30:24 GMT
   server: envoy

   可以看到，响应头中的Content-Type和Content-Length仍然保持了大写。