Problema do proxy reverso Nginx para código de resposta 4xx

Question

Eu configurei o nginx para fazer proxy do pedido que vem para a porta 8000, para rotear para um ip diferente. Na configuração eu também adiciono o cabeçalho Access-control-Allow-Origin. Isso funciona bem se o servidor estiver respondendo com códigos de resposta 2xx. Mas se o servidor responder com códigos de resposta 4xx, não inclui o cabeçalho mencionado abaixo

server {
listen *:8000;

ssl                     on;
ssl_certificate         /etc/nginx/ssl/axis.crt;
ssl_certificate_key     /etc/nginx/ssl/axisPrivate.key;
server_name             website.com;
ssl_protocols           SSLv2 SSLv3 TLSv1;
ssl_ciphers             ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv3:+EXP;
access_log /var/log/nginx/nginx.vhost.access.log;
error_log /var/log/nginx/nginx.vhost.error.log;

location / {
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_pass https://api;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_ssl_session_reuse off;
    proxy_set_header Host $http_host;

    proxy_redirect off;
    proxy_intercept_errors off;  
# Simple requests
    if ($request_method ~* "(GET|POST|PUT)") {
      add_header "Access-Control-Allow-Origin" "https://website.com";
    }

    # Preflighted requests
    if ($request_method = OPTIONS ) {
      add_header "Access-Control-Allow-Origin"  "https://website.com";
      add_header "Access-Control-Allow-Methods" "GET,PUT,POST, OPTIONS, HEAD";
      add_header "Access-Control-Allow-Headers" "Authorization, Origin, X-Requested-With, Content-Type, Accept,access-control-allow-methods,access-control-allow-origin";
      return 200;
    }

}
}

upstream api {
 server ip:port;
}

Como o cabeçalho está sem o Access-Control-Allow-Origin, o navegador está bloqueando qualquer ação a ser executada na resposta.

Erro no login do navegador:

POST https://website.com:8000/employee 409 ()
EmployeeRegistration:1 Failed to load https://website.com:8000/employee: No 'Access-Control-Allow-Origin' header is present on the requested resource. 
Origin 'https://website.com' is therefore not allowed access. The response had HTTP status code 409.

    

Answer 1

Este é o comportamento pretendido :

Syntax: add_header name value [always];

Default: — Context: http, server, location, if in location

Adds the specified field to a response header provided that the response code equals 200, 201 (1.3.10), 204, 206, 301, 302, 303, 304, 307 (1.1.16, 1.0.13), or 308 (1.13.0). The value can contain variables.

There could be several add_header directives. These directives are inherited from the previous level if and only if there are no add_header directives defined on the current level.

If the always parameter is specified (1.7.5), the header field will be added regardless of the response code.

Você precisa da palavra-chave sempre na diretiva add_header .