#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
#include <ngx_http_proxy_handler.h>


int ngx_http_proxy_copy_header(ngx_http_proxy_ctx_t *p,
                               ngx_http_proxy_headers_in_t *headers_in)
{
    int                  i;
    ngx_table_elt_t     *ho, *h;
    ngx_http_request_t  *r;

    r = p->request;

    h = headers_in->headers->elts;
    for (i = 0; i < headers_in->headers->nelts; i++) {

        if (&h[i] == headers_in->connection) {
            continue;
        }
    
        if (p->accel) {
            if (&h[i] == headers_in->date
                || &h[i] == headers_in->accept_ranges) {
                continue;
            }

            if (&h[i] == headers_in->x_accel_expires
                && !p->lcf->pass_x_accel_expires)
            {
                continue;
            } 
    
            if (&h[i] == headers_in->server && !p->lcf->pass_server) {
                continue;
            } 
        }
    
        if (&h[i] == headers_in->content_type) {
            r->headers_out.content_type = &h[i];
            r->headers_out.content_type->key.len = 0;
            continue;
        }

        if (!(ho = ngx_http_add_header(&r->headers_out, ngx_http_headers_out)))
        {
            return NGX_ERROR;
        }
    
        *ho = h[i];
    
        /*
         * ngx_http_header_filter() does not handle specially
         * the following headers if they are set:
         *     r->headers_out.server,
         *     r->headers_out.date,
         *     r->headers_out.content_length
         */

        if (&h[i] == headers_in->server) {
            r->headers_out.server = ho;
            continue;
        }

        if (&h[i] == headers_in->date) {
            r->headers_out.date = ho;
            continue;
        }

        if (&h[i] == headers_in->content_length) {
            r->headers_out.content_length = ho;
            r->headers_out.content_length_n = ngx_atoi(ho->value.data,
                                                       ho->value.len);
            continue;
        }
    }

    return NGX_OK;
}