    001// Copyright 2008, 2011 The Apache Software Foundation
    002//
    003// Licensed under the Apache License, Version 2.0 (the "License");
    004// you may not use this file except in compliance with the License.
    005// You may obtain a copy of the License at
    006//
    007// http://www.apache.org/licenses/LICENSE-2.0
    008//
    009// Unless required by applicable law or agreed to in writing, software
    010// distributed under the License is distributed on an "AS IS" BASIS,
    011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012// See the License for the specific language governing permissions and
    013// limitations under the License.
    014
    015package org.apache.tapestry5.services;
    016
    017import org.apache.tapestry5.ioc.services.ServiceOverride;
    018
    019/**
    020 * Used when switching between normal/insecure (HTTP) and secure (HTTPS) mode. When a switch occurs, it is no longer
    021 * possible to use just paths, instead absolute URLs (including the scheme, hostname and possibly port) must be
    022 * generated. The default implementation of this is simple-minded: it just tacks the correct scheme in front of
    023 * {@link org.apache.tapestry5.services.Request#getServerName()}. In production, behind a firewall, it is often
    024 * necessary to do a bit more, since <code>getServerName()</code> will often be the name of the internal server (not
    025 * visible to the client web browser), and a hard-coded name of a server that <em>is</em> visible to the web browser
    026 * is needed. Further, in testing, non-default ports are often used. In those cases, an overriding contribution to the
    027 * {@link ServiceOverride} service will allow a custom implementation to supercede the default version. You may also
    028 * contribute application specific values for the following {@link org.apache.tapestry5.SymbolConstants}:
    029 * {@link org.apache.tapestry5.SymbolConstants#HOSTNAME}, {@link org.apache.tapestry5.SymbolConstants#HOSTPORT} and
    030 * {@link org.apache.tapestry5.SymbolConstants#HOSTPORT_SECURE} to alter the behavior of the default BaseURLSource
    031 * implementation. The default values for the SymbolConstants require {@link org.apache.tapestry5.services.Request}
    032 * context to be available. If you contribute specific values for the specified SymbolConstants, it's safe to use
    033 * the default implementation of this service outside of request context, for example in a batch job. For
    034 * {@link org.apache.tapestry5.SymbolConstants#HOSTNAME}, a value starting with a dollar sign ($) will be resolved
    035 * using {@link java.lang.System#getenv()} - contributing "$HOSTNAME" for {@link org.apache.tapestry5.SymbolConstants#HOSTNAME}
    036 * is the most sensible choice for a dynamic value that doesn't use
    037 * {@link org.apache.tapestry5.services.Request#getServerName()}.
    038 */
    039public interface BaseURLSource
    040{
    041    /**
    042     * Returns the base portion of the URL, before the context path and servlet path are appended. The return value
    043     * should <em>not</em> end with a slash; it should end after the host name, or after the port number. The context
    044     * path, servlet path, and path info will be appended to the returned value.
    045     *
    046     * @param secure
    047     *            whether a secure "https" or insecure "http" base URL should be returned
    048     * @return the base URL ready for additional extensions
    049     */
    050    String getBaseURL(boolean secure);
    051}