static ngx_int_t
ngx_http_uwsgi_process_header(ngx_http_request_t *r)
{
    ngx_str_t                      *status_line;
    ngx_int_t                       rc, status;
    ngx_table_elt_t                *h;
    ngx_http_upstream_t            *u;
    ngx_http_upstream_header_t     *hh;
    ngx_http_upstream_main_conf_t  *umcf;

    umcf = ngx_http_get_module_main_conf(r, ngx_http_upstream_module);

    for ( ;; ) {

        rc = ngx_http_parse_header_line(r, &r->upstream->buffer, 1);

        if (rc == NGX_OK) {

            /* a header line has been parsed successfully */

            h = ngx_list_push(&r->upstream->headers_in.headers);
            if (h == NULL) {
                return NGX_ERROR;
            }

            h->hash = r->header_hash;

            h->key.len = r->header_name_end - r->header_name_start;
            h->value.len = r->header_end - r->header_start;

            h->key.data = ngx_pnalloc(r->pool,
                                      h->key.len + 1 + h->value.len + 1
                                      + h->key.len);
            if (h->key.data == NULL) {
                return NGX_ERROR;
            }

            h->value.data = h->key.data + h->key.len + 1;
            h->lowcase_key = h->key.data + h->key.len + 1 + h->value.len + 1;

            ngx_memcpy(h->key.data, r->header_name_start, h->key.len);
            h->key.data[h->key.len] = '\0';
            ngx_memcpy(h->value.data, r->header_start, h->value.len);
            h->value.data[h->value.len] = '\0';

            if (h->key.len == r->lowcase_index) {
                ngx_memcpy(h->lowcase_key, r->lowcase_header, h->key.len);

            } else {
                ngx_strlow(h->lowcase_key, h->key.data, h->key.len);
            }

            hh = ngx_hash_find(&umcf->headers_in_hash, h->hash,
                               h->lowcase_key, h->key.len);

            if (hh && hh->handler(r, h, hh->offset) != NGX_OK) {
                return NGX_ERROR;
            }

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "http uwsgi header: \"%V: %V\"", &h->key, &h->value);

            continue;
        }

        if (rc == NGX_HTTP_PARSE_HEADER_DONE) {

            /* a whole header has been parsed successfully */

            ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "http uwsgi header done");

            u = r->upstream;

            if (u->headers_in.status_n) {
                return NGX_OK;
            }

            if (u->headers_in.status) {
                status_line = &u->headers_in.status->value;

                status = ngx_atoi(status_line->data, 3);
                if (status == NGX_ERROR) {
                    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                                  "upstream sent invalid status \"%V\"",
                                  status_line);
                    return NGX_HTTP_UPSTREAM_INVALID_HEADER;
                }

                u->headers_in.status_n = status;
                u->headers_in.status_line = *status_line;

            } else if (u->headers_in.location) {
                u->headers_in.status_n = 302;
                ngx_str_set(&u->headers_in.status_line,
                            "302 Moved Temporarily");

            } else {
                u->headers_in.status_n = 200;
                ngx_str_set(&u->headers_in.status_line, "200 OK");
            }

            if (u->state) {
                u->state->status = u->headers_in.status_n;
            }

            return NGX_OK;
        }

        if (rc == NGX_AGAIN) {
            return NGX_AGAIN;
        }

        /* there was error while a header line parsing */

        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "upstream sent invalid header");

        return NGX_HTTP_UPSTREAM_INVALID_HEADER;
    }
}