Return a specific/200 status code for a particular URL prefix in Haproxy

Question

In Nginx we can return a specific status code to URL prefix like this.

location /api { return 200; }

How can we achieve the same in Haproxy?.

Gone through Haproxy ACL but couldn't find any.

The requirement is not clear, returning a code status is a web server feature rather than a reverse proxy one. HAProxy is not a web server. Are you using HAProxy as reverse proxy / load balancer ? and you want to override a backend response ? — Mo3m3n, Aug 18 '17 at 12:08
yes, want to override the backend response by ignoring the URI prefix or giving a 200 status code — Augustin, Aug 18 '17 at 21:00

score 3 · Accepted Answer · answered Sep 25 '19 at 17:29

This can be accomplished by using a lua response script. I already use one to set the CORS headers for the preflight response.

My rule is the following:

global
    ...
    lua-load /etc/haproxy/200.lua

frontend
    bind ...
    ...
    use_backend http_200 if ...

backend http_200
    http-request use-service lua.200-response

Lua script in /etc/haproxy/200.lua:

# 200.lua
core.register_service("200-response", "http", function(applet)
    local response = ""
    applet:set_status(200)
    applet:add_header("Content-Length", "0")
    applet:start_response()
    applet:send(response)
end)

score 2 · Answer 2 · answered Dec 30 '21 at 11:11

2

For completeness, from version 2.2 you can return dynamic content like this

http-request return status 200 content-type "text/plain" lf-string "Hello"

Return a specific/200 status code for a particular URL prefix in Haproxy

2 Answers2