在Haproxy中添加CORS以实现Haproxy的错误响应

Question

我有以下 haproxy.cfg。

这会将必要的 CORS 标头添加到我的后端的响应中，效果很好。我面临的问题是，如果 haproxy 接口的服务器超时（即超过下面的 30 秒服务器超时），haproxy 本身会发送 504 响应，该响应没有我需要的 CORS 标头。我如何让它动态地做到这一点（静态地只是在

/etc/haproxy/errors/504.http

中添加此标头）？

global
        log /dev/log    local0
        log /dev/log    local1 notice
        chroot /var/lib/haproxy
        stats socket /run/haproxy/admin.sock mode 660 level admin
        stats timeout 30s
        user haproxy
        group haproxy
        daemon

        # Default SSL material locations
        ca-base /etc/ssl/certs
        crt-base /etc/ssl/private

        ssl-default-bind-ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA>
        ssl-default-bind-ciphersuites TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256
        ssl-default-bind-options ssl-min-ver TLSv1.2 no-tls-tickets

defaults
        log     global
        mode    http
        option  httplog
        option  dontlognull
        timeout connect 5s
        timeout client  30s
        timeout server  30s

http-errors json
        errorfile 400 /etc/haproxy/errors/400.http
        errorfile 403 /etc/haproxy/errors/403.http
        errorfile 408 /etc/haproxy/errors/408.http
        errorfile 500 /etc/haproxy/errors/500.http
        errorfile 502 /etc/haproxy/errors/502.http
        errorfile 504 /etc/haproxy/errors/504.http

frontend www-https
    bind *:80
    bind *:443 ssl crt /etc/ssl/mywebsite.pem
    errorfiles json


    http-response del-header Access-Control-Allow-Origin
    capture request header origin len 128
    http-response set-header Access-Control-Allow-Origin %[capture.req.hdr(0)] if { capture.req.hdr(0) -m found }
    http-response set-header Access-Control-Allow-Methods "GET, HEAD, OPTIONS, POST, PUT" if { capture.req.hdr(0) -m found }
    http-response set-header Access-Control-Allow-Credentials true if { capture.req.hdr(0) -m found }



    # Redirect HTTP to  HTTPS
    redirect scheme https code 301 if !{ ssl_fc }
    mode http

    #Backend to use if no URL specified
    default_backend myBackend


backend myBackend
  server myServer <the ip of the server>

Answer 1

我在 serverfault stackexchange 上问了同样的问题，并为任何想要这样做的人得到了答案：

https://serverfault.com/questions/1136690/adding-custom-headers-on-error-responses-from-haproxy