help request: Add a header if exist not overwrite

[purekeeper]

Description

How can i add a header if not exist ,don't overwite if exist. Which plugin should used, proxy-rewite is not suitable,beacause it will overwrite if exist

Environment

• APISIX version (run apisix version):
• Operating system (run uname -a):
• OpenResty / Nginx version (run openresty -V or nginx -V):
• etcd version, if relevant (run curl http://127.0.0.1:9090/v1/server_info):
• APISIX Dashboard version, if relevant:
• Plugin runner version, for issues related to plugin runners:
• LuaRocks version, for installation issues (run luarocks --version):

[soulbird]

Maybe, we can add a configuration to determine if headers needs to be rewritten

[tokers]

@purekeeper Currently, you may support this by the serverless plugin: https://apisix.apache.org/docs/apisix/plugins/serverless.

[kwanhur]

• If the header was on request, proxy-rewrite plugin is a better choice.
• If it's on response, response-rewrite plugin is a better choice.

But both them have no support .

Support to set header if nonexistent, they'll easier to reach intention than serverless plugin.

[tzssangglass]

Another compromise is to use the vars on the route to distinguish between routes with a specified header and those without one, and to handle them separately.

IMO, don't override if it exists: this will cause to check the all headers, which is inefficient.

[PGDream]

suggest request add、remove、replace header plugin.

[github-actions]

This issue has been marked as stale due to 350 days of inactivity. It will be closed in 2 weeks if no further activity occurs. If this issue is still relevant, please simply write any comment. Even if closed, you can still revive the issue at any time or discuss it on the dev@apisix.apache.org list. Thank you for your contributions.

[soulbird]

solved in #8336