Function md_require_https_maybe

modules/md/mod_md.c:1482–1542

/* Require Https hook */

static int md_require_https_maybe(request_rec *r)
{
    const md_srv_conf_t *sc;
    apr_uri_t uri;
    const char *s, *host;
    const md_t *md;
    int status;

    /* Requests outside the /.well-known path are subject to possible
     * https: redirects or HSTS header additions.
     */
    sc = ap_get_module_config(r->server->module_config, &md_module);
    if (!sc || !sc->assigned || !sc->assigned->nelts || !r->parsed_uri.path
        || !strncmp(WELL_KNOWN_PREFIX, r->parsed_uri.path, sizeof(WELL_KNOWN_PREFIX)-1)) {
        goto declined;
    }

    host = ap_get_server_name_for_url(r);
    md = md_get_for_domain(r->server, host);
    if (!md) goto declined;

    if (ap_ssl_conn_is_ssl(r->connection)) {
        /* Using https:
         * if 'permanent' and no one else set a HSTS header already, do it */
        if (md->require_https == MD_REQUIRE_PERMANENT
            && sc->mc->hsts_header && !apr_table_get(r->headers_out, MD_HSTS_HEADER)) {
            apr_table_setn(r->headers_out, MD_HSTS_HEADER, sc->mc->hsts_header);
        }
    }
    else {
        if (md->require_https > MD_REQUIRE_OFF) {
            /* Not using https:, but require it. Redirect. */
            if (r->method_number == M_GET) {
                /* safe to use the old-fashioned codes */
                status = ((MD_REQUIRE_PERMANENT == md->require_https)?
                          HTTP_MOVED_PERMANENTLY : HTTP_MOVED_TEMPORARILY);
            }
            else {
                /* these should keep the method unchanged on retry */
                status = ((MD_REQUIRE_PERMANENT == md->require_https)?
                          HTTP_PERMANENT_REDIRECT : HTTP_TEMPORARY_REDIRECT);
            }

            s = ap_construct_url(r->pool, r->uri, r);
            if (APR_SUCCESS == apr_uri_parse(r->pool, s, &uri)) {
                uri.scheme = (char*)"https";
                uri.port = 443;
                uri.port_str = (char*)"443";
                uri.query = r->parsed_uri.query;
                uri.fragment = r->parsed_uri.fragment;
                s = apr_uri_unparse(r->pool, &uri, APR_URI_UNP_OMITUSERINFO);
                if (s && *s) {
                    apr_table_setn(r->headers_out, "Location", s);
                    return status;
                }
            }
        }
    }