/*

  * 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;

 /**

  * Given the RAW content of a URL, determine if we're looking at an RSS file or

  * an HTML file.  We also return the given RSS version or Atom version.

  * 

  * @author <a href="mailto:burton@apache.org">Kevin A. Burton (burtonator)</a>

  * @version $Id: ContentDetector.java 373614 2006-01-30 22:31:21Z mvdb $

  */

 public class ContentDetector {

     /**

      * Return true if the given content seems to be RSS.  This is going to be a

      * cheat because really we have no way of telling if this is RSS other than if

      * it is XML and it starts with an RSS 1.0, 2.0, 0.91 or 0.9 decl

      *

      * 

      */

     public static ContentDetectorResult detect( String content ) throws Exception {

         ContentDetectorResult result = new ContentDetectorResult();

         result.isHTML = isHTMLContent( content );

         result.isRSS = ( isRSS_1_0_Content( content ) ||

                          isRSS_2_0_Content( content ) ||

                          isRSS_0_9_0_Content( content ) ||

                          isRSS_0_9_1_Content( content ) ||

                          isRSS_0_9_2_Content( content ) );

         result.isAtom = isAtomContent( content );

         result.isFeed = result.isRSS || result.isAtom;

         return result;

     }

     /**

      * Return true if this is RSS 1.0 content

      *

      * 

      */

     public static boolean isRSS_1_0_Content( String content ) throws Exception {

         //do a search for the RSS 1.0 namespace.  This is a bit of a trick right

         //now.

         return content.indexOf( "http://purl.org/rss/1.0/" ) != -1;

     }

     /**

      * Return true if this is RSS 2.0 content

      *

      * 

      */

     public static boolean isRSS_0_9_1_Content( String content ) throws Exception {

         //look for the beginning of the RSS element

         return content.indexOf( "<rss" ) != -1;

     }

     /**

      * Return true if this is RSS 0.9.2 content

      *

      * 

      */

     public static boolean isRSS_0_9_2_Content( String content ) throws Exception {

         //same check for RSS 0.9.1

         return isRSS_0_9_1_Content( content );

     }

     /**

      * Return true if this is RSS 2.0 content

      *

      * 

      */

     public static boolean isRSS_2_0_Content( String content ) throws Exception {

         return isRSS_0_9_1_Content( content );

     }

     /**

      * Return true if this is RSS 2.0 content

      *

      * 

      */

     public static boolean isRSS_0_9_0_Content( String content ) throws Exception {

         //FIXME: look for the RDF namespace and the RSS DTD namespace

         return content.indexOf( "http://my.netscape.com/rdf/simple/0.9/" ) != -1;

     }

     public static boolean isAtomContent( String content ) throws Exception {

         return content.indexOf( "http://purl.org/atom/ns#" ) != -1;

     }

     /**

      * Return true if this is RSS 2.0 content

      *

      * 

      */

     public static boolean isHTMLContent( String content ) throws Exception {

         //look for the beginning of the RSS element

         return content.indexOf( "<html" ) != -1;

     }

     public static void main( String[] args ) {

         try { 

             //System.out.println( RSSContentVerifier.isRSSContent( new URL( args[0] ) ) );

         } catch ( Throwable t ) {

             t.printStackTrace();

         }

     }

 }