/*

  * Copyright 1999,2004 The Apache Software Foundation.

  * 

  * Licensed under the Apache License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  * 

  *      http://www.apache.org/licenses/LICENSE-2.0

  * 

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.apache.commons.feedparser.locate.blogservice;

 import java.net.MalformedURLException;

 import java.util.regex.*;

 import org.apache.commons.feedparser.FeedParserException;

 import org.apache.commons.feedparser.locate.*;

 /**

  * Models the Blosxom blog service, encapsulating whether a given weblog

  * is this type of service and where it usually keeps its feeds.

  * 

  * @author Brad Neuberg, bkn3@columbia.edu

  */

 public class Blosxom extends BlogService {

     /** A pattern used to discover Blosxom blogs. */

     private static Pattern blosxomPattern =

                 Pattern.compile("alt=[\"' ]powered by blosxom[\"' ]",

                                 Pattern.CASE_INSENSITIVE);

     /** Returns whether we can trust the results of this blog service's 

      *  autodiscovery links.  For example, TextAmerica returns invalid 

      *  autodiscovery results.

      */

     public boolean hasValidAutoDiscovery() {

         return true;

     }

     /** Returns whether we should follow HTTP redirects for this blog service.

      *  Some services don't implement HTTP redirects correctly, while others,

      *  like Xanga, require it.

      */

     public boolean followRedirects() {

         return false;

     }

     /** Determines if the weblog at the given resource and with the given

      *  content is this blog service.

      * @param resource A full URI to this resource, such as 

      * "http://www.codinginparadise.org".

      * @param content The full HTML content at the resource's URL.

      * @throws FeedParserException Thrown if an error occurs while 

      * determining the type of this weblog.

      */

     public boolean isThisService(String resource, String content)

                                                 throws FeedParserException {

         boolean results = false;

         // This is the only kind of blog that we need to check for a 

         // 'Powered by Blosxom'.  We do this with the alt= value on the

         // Powered By image.

         // FIXME: This might be fragile, but it is used across all of the

         // Blosxom blogs I have looked at so far. Brad Neuberg, bkn3@columbia.edu

         Matcher blosxomMatcher = blosxomPattern.matcher(content);

         results = blosxomMatcher.find();

         return results;

     }

     /**

      * Returns an array of FeedReferences that contains information on the

      * usual locations this blog service contains its feed.  The feeds should

      * be ordered by quality, so that higher quality feeds come before lower

      * quality ones (i.e. you would want to have an Atom FeedReference

      * object come before an RSS 0.91 FeedReference object in this list).

      * @param resource A URL to the given weblog that might be used to build

      * up where feeds are usually located.

      * @param content The full content of the resource URL, which might

      * be useful to determine where feeds are usually located.  This can be

      * null.

      * @throws FeedParserException Thrown if an error occurs while trying

      * to determine the usual locations of feeds for this service.

      */

     public FeedReference[] getFeedLocations(String resource,

                                             String content)

                                                 throws FeedParserException {

         // there is sometimes an index.rss20 file, but Blosxom has a bug where

         // it incorrectly responds to HTTP HEAD requests for that file,

         // saying that it exists when it doesn't.  Most sites don't seem

         // to have this file so we don't include it here. 

         // Brad Neuberg, bkn3@columbia.edu

         FeedReference[] blosxomLocations = 

             { new FeedReference("index.rss", FeedReference.RSS_MEDIA_TYPE) };

         return blosxomLocations;

     }

     /** This method takes a resource, such as "http://www.codinginparadise.org/myweblog.php",

      *  and gets the path necessary to build up a feed, such as 

      *  "http://www.codinginparadise.org/".  Basicly it appends a slash 

      *  to the end if there is not one, and removes any file names that 

      *  might be at the end, such as "myweblog.php".

      *

      *  There is a special exception for some Blosxom blogs,

      *  which have things inside of a cgi-script and 'hang' their RSS files

      *  off of this cgi-bin.  For example, 

      *  http://www.bitbucketheaven.com/cgi-bin/blosxom.cgi has its RSS file

      *  at http://www.bitbucketheaven.com/cgi-bin/blosxom.cgi/index.rss, so

      *  we must return the blosxom.cgi at the end as well for this method.

      * 

      *  @throws MalformedURLException Thrown if the given resource's URL is 

      *  incorrectly formatted.

      */

     public String getBaseFeedPath( String resource ) {

         // strip off any query string or anchors

         int end = resource.lastIndexOf( "#" );

         if ( end != -1 )

             resource = resource.substring( 0, end );

         end = resource.lastIndexOf( "?" );

         if ( end != -1 )

             resource = resource.substring( 0, end );

         if ( ! resource.endsWith( "/" ) ) {

             resource = resource + "/";

         }

         return resource;

     }

 }