001    // Copyright 2008 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    
015    package org.apache.tapestry.services;
016    
017    /**
018     * Used when switching between normal/insecure (HTTP) and secure (HTTPS) mode.  When a switch occurs, it is no longer
019     * possible to use relative URLs, instead absolute URLs must be generated. The default implementation of this is
020     * simple-minded: it just tacks the correct scheme in front of {@link org.apache.tapestry.services.Request#getServerName()}.
021     * In production, behind a firewall, it is often necessary to do a bit more, since <code>getServerName()</code> will
022     * often be the name of the internal server (not visible to the client web browser), and a hard-coded name of a server
023     * that <em>is</em> visible to the web browser is needed.  Further, in testing, non-default ports are often used. In
024     * those cases, an overriding contribution to the {@link org.apache.tapestry.services.Alias} service will allow a custom
025     * implementation to supercede the default version.
026     */
027    public interface BaseURLSource
028    {
029        /**
030         * Returns the base portion of the URL, before the context path and servlet path are appended. The return value
031         * should <em>not</em> end with a slash; it should end after the host name, or after the port number.  The context
032         * path, servlet path, and path info will be appended to the returned value.
033         *
034         * @param secure whether a secure "https" or insecure "http" base URL should be returned
035         * @return the base URL ready for additional extensions
036         */
037        String getBaseURL(boolean secure);
038    }