#Header Modification

#Basic Concepts

When a request is received, header modification allows adjusting request headers before forwarding to the backend. Similarly, when a response is received, it allows adjusting response headers before they are returned to the client.

#use annotations

Annotation values are JSON strings containing the config.

type RewriteRequestConfig struct {
	Headers       map[string]string   `json:"headers,omitempty"`         // set header
	HeadersVar    map[string]string   `json:"headers_var,omitempty"`     // set header, which values are variable name
	HeadersRemove []string            `json:"headers_remove,omitempty"`  // remove header
	HeadersAdd    map[string][]string `json:"headers_add,omitempty"`     // add header, which values could be multiple
	HeadersAddVar map[string][]string `json:"headers_add_var,omitempty"` // add header, which values could be multiple and which values are variable name
}
type RewriteResponseConfig struct {
	Headers       map[string]string   `json:"headers,omitempty"`         // set header
	HeadersRemove []string            `json:"headers_remove,omitempty"`  // remove header
	HeadersAdd    map[string][]string `json:"headers_add,omitempty"`     // add header, which values could be multiple
}

Note: in *_var maps the key is the header name and the value is the ALB context variable name. For example, add the following annotation to an Ingress:

alb.ingress.cpaas.io/rewrite-request: '{
    "headers_var": {
        "x-my-host": "http_host"
    }
}'

will add key x-my-host and value of request host header to request header. you can refer to the nginx variable for the variable names.

ALB provides additional variables:

#examples

To add an Authorization header from a cookie, you can use:

alb.ingress.cpaas.io/rewrite-request: '{"headers_var":{"Authorization":"cookie_auth_token"}}'

To set HSTS, you can use:

alb.rule.cpaas.io/rewrite-response: |
  { "headers": { "Strict-Transport-Security": "max-age=63072000; includeSubDomains; preload"} }

#Trademark Notice

NGINX® is a registered trademark of F5, Inc. in the U.S. and in other countries.

Alauda is an independent vendor. This product is not affiliated with, endorsed by, or sponsored by F5, Inc. All trademarks are the property of their respective owners and are used here for identification purposes only.